Re: [PSES] Friday question: AI-assisted software development for Safety Function?

[Ralph McDiarmid]

For AI, there may be more “sizzle than steak”.  I found this a good read:

 

Will A.I. Be a Bust? A Wall Street Skeptic Rings the Alarm. - The New York 
Times (nytimes.com) 

 

 

Ralph

 

From: Douglas Powell mailto:doug...@gmail.com> > 
Sent: October 4, 2024 9:44 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] Friday question: AI-assisted software development for Safety 
Function?

 

All, 

 

Some predict that by 2028, 75% of enterprise software engineers will use 
AI-coding assistants, up from less than 10% in early 2023.  By 2025, estimates 
are that 80% of the software development life cycle will involve generative AI 
code generation, potentially enhancing developer productivity by up to 75% in 
some cases. As of 2024, 46% of developers are already using ChatGPT, while 30% 
rely on GitHub Copilot for some coding assistance. This shows that AI tools are 
already becoming commonplace in software development workflows. I also learned 
that AI-powered tools treat computer languages as natural languages, enabling 
faster and smoother coding with reduced friction. And this rapid trend is 
expected to accelerate in the coming years.

What I don't know is how this may include software development for embedded 
controllers and if anyone anywhere has yet succeeded in writing software that 
is UL 1998 compliant while using AI assistance.  
https://www.ey.com/en_in/services/technology/ai-augmented-software-development-a-new-era-of-efficiency-and-innovation
 


 

As developers of programmable devices keep adding safety features to 
controllers, I really believe that if someone succeeds in a UL 1998-approved 
controller, it could very well rewrite how we do things in the future.

 

Any thoughts, any concerns?

 

~Doug

 

Douglas E Powell

Laporte, Colorado, USA

  LinkedIn

  

 

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Re: [PSES] Friday question: AI-assisted software development for Safety Function?

[Ralph McDiarmid]

For AI, there may be more sizzle that steak.  I found this a good read

 

Will A.I. Be a Bust? A Wall Street Skeptic Rings the Alarm. - The New York 
Times (nytimes.com) 

 

 

Ralph

 

From: Douglas Powell  
Sent: October 4, 2024 9:44 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Friday question: AI-assisted software development for Safety 
Function?

 

All, 

 

Some predict that by 2028, 75% of enterprise software engineers will use 
AI-coding assistants, up from less than 10% in early 2023.  By 2025, estimates 
are that 80% of the software development life cycle will involve generative AI 
code generation, potentially enhancing developer productivity by up to 75% in 
some cases. As of 2024, 46% of developers are already using ChatGPT, while 30% 
rely on GitHub Copilot for some coding assistance. This shows that AI tools are 
already becoming commonplace in software development workflows. I also learned 
that AI-powered tools treat computer languages as natural languages, enabling 
faster and smoother coding with reduced friction. And this rapid trend is 
expected to accelerate in the coming years.

What I don't know is how this may include software development for embedded 
controllers and if anyone anywhere has yet succeeded in writing software that 
is UL 1998 compliant while using AI assistance.  
https://www.ey.com/en_in/services/technology/ai-augmented-software-development-a-new-era-of-efficiency-and-innovation
 


 

As developers of programmable devices keep adding safety features to 
controllers, I really believe that if someone succeeds in a UL 1998-approved 
controller, it could very well rewrite how we do things in the future.

 

Any thoughts, any concerns?

 

~Doug

 

Douglas E Powell

Laporte, Colorado, USA

  LinkedIn

  

 

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[PSES] power converters onboard yachts

[Ralph McDiarmid]

If a yacht is manufactured in the USA and then sails aboard to eventually
dock at a port somewhere in the EU, does its onboard electronics require CE
mark ?I'm thinking specifically of power converters connecting to shore
power.

 

Ralph


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Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal condition - Fail

[Ralph McDiarmid]

I concur with the suggestions James has made on this topic.

Ralph

-Original Message-
From: James Pawson (U3C)  
Sent: September 9, 2024 12:21 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal 
condition - Fail

Hi Amund,

Throwing in another $0.02...

For CB scheme reports, my experience is that the lab will take a very "black or 
white" approach to the standard. There is often no room for the manufacturer to 
risk assess or carry out additional testing for edge cases. In this case it 
sounds like the lab are taking the "we are not sure what is going on therefore 
fail" even though it might meet the requirements.

To assess the risk, if you have access to a thermal chamber and a hipot tester, 
why not carry out your own measurements of dielectric strength at temperature? 
You could use this to help justify your position? Although the lab is just as 
likely to say no as you are not the manufacturer of the component! 

All the best
James

James Pawson
Managing Director & EMC Problem Solver

Unit 3 Compliance Ltd
EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy

www.unit3compliance.co.uk | ja...@unit3compliance.co.uk 
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Registered in England and Wales # 10574298

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Every morning my full attention is on consultancy, testing, and troubleshooting 
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For inquiries, bookings, and testing updates please send us an email on 
he...@unit3compliance.co.uk or call 01274 911747. Our lead times for testing 
and consultancy are typically 4-5 weeks.

-Original Message-
From: Ralph McDiarmid  
Sent: Wednesday, September 4, 2024 5:39 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal 
condition - Fail

Hi Amund,

The standard I have access to, IEC 62368-1:2018 RLV © IEC 2018, has clause 
4.1.2 Use of Components.  Nowhere in that clause could I find a statement 
supporting what the lab thinks is needed.  The noun "critical component" does 
not appear anywhere in the 2018 version, but I suggest it is a synonym for the 
term "safeguard" defined and used throughout IEC 62368-1.  The lab really 
should be using language and terminology aligned with the standard being 
applied.

In other standards that do include Abnormal Condition tests, component 
temperatures are not a pass/fail criterion in that operating condition.  It 
appears to be so with IEC 62368, but it's not explicit and seems open to 
interpretation.

However, in Normal Condition at +55C ambient it looks like you've got an issue 
with at least one component.   You might need to change the upper end of your 
operating temperature range.  (55C is very high for outdoor equipment.)

Ralph

-Original Message-
From: Amund Westin 
Sent: September 4, 2024 2:56 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal 
condition - Fail

Ralph,

“The standard also does not accept that critical components get a temperature 
above what is specified in the test report for that component»“

The lab refer to Clause 4.1.2.
Right now, I don't have access to the standard, so I cant check the text.

Best ragards Amund




On 2024-09-04 09:15, Amund Westin wrote:
> Thanks all for good comments!
> 
> Ralph:
> I'm still waiting for lab feedback on this one :“ The standard also 
> does not accept that critical components get a temperature above what 
> is specified in the test report for that component». “ I have a 
> feeling they will reply : Annex G.5.3.3.2, even though it is not a 
> transformer, but a DC/DC module.
> I'll post the lab feedback when it comes in.
> 
> 
> John W:
> Improvement of ventilation is an option that is under discussion in 
> the R&D now. Trick to do, because of current design.
> 
> 
> We got new information yesterday and I summarize the current situation:
> 1) Abnormal condition: DCDCmodule spec +85C, measured under to be 91C 
> under abnormal condition
> 2) Normal condition: DCDCmodule spec +85C, measured to be 83C under 
> normal condition (+25C ambient)
> 3) Normal condition: DCDCmodule spec +85C, measured to be 88C under 
> normal condition (+55C ambient, spec final product is -40C to +55C))
> 
> 
> Facts:
> DCDCmodule is CB certified (-40C to +85C) DCDCmodule is places inside 
> a fire enclosure DCDCmodule is not accessable / touchable Final 
> product with DCDCmodule have been running in the field +20 years 
> without failure.
> 
> 
> I'll return with more information.
> 
> 
> Best regards Amund
> 
> 
> 
> 
> On 2024-09-03 16:52,

Re: [PSES] : IEC 61000-2-4 scope

[Ralph McDiarmid]

Thanks Karen.  Your list of general requirements is very close to what I 
suggested to my client some time ago, but their customer ( a large automotive 
manufacturer) seems to have other ideas.  They are currently negotiating a list 
of EMC requirements for the inverter.

 

Ralph

 

From: Karen Burnham  
Sent: September 6, 2024 11:19 AM
To: rmm.priv...@gmail.com
Cc: EMC-PSTC@listserv.ieee.org
Subject: Re: [PSES] : IEC 61000-2-4 scope

 

Usually a component going onto a vehicle would meet automotive standards: CISPR 
25, ISO 11452, ECE Reg 10, depending on customer, market, etc. 


Best,

-=-Karen Burnham

President and Chief EMC Engineer, NCE

EMC United, Inc.

www.emcunited.com <http://www.emcunited.com> 

 

 

On Fri, Sep 6, 2024 at 12:15 PM Ralph McDiarmid mailto:rmm.priv...@gmail.com> > wrote:

My turn to ask a question to the group of experts.

 

Reference:

IEC 61000-2-4:2024

Electromagnetic compatibility (EMC) - Part 2-4: Environment - Compatibility 
levels in power distribution systems in industrial locations for low-frequency 
conducted disturbances

 

My client would like to know if standard IEC 61000-2-4 is applicable to an 
inverter that is intended for permanent installation in a motor vehicle.  The 
inverter has no connection to a.c. mains and does not have an a.c. input power 
port.  It’s merely a 24Vdc to 230Vac/50Hz inverter.

 

I think this IEC standard is clearly out of scope for this class of equipment, 
but if client’s customer insists (a big automotive manufacturer) I’d like to be 
able craft a technical justification to waive application of the standard.

 

The standard appears only to address conducted disturbances which may be 
present on non-public (industrial) a.c. power networks and the EMC immunity of 
equipment connected to those networks.

 

Thank you,

 

 

Ralph

 


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Re: [PSES] : IEC 61000-2-4 scope

[Ralph McDiarmid]

My turn to ask a question to the group of experts.

 

Reference:

IEC 61000-2-4:2024

Electromagnetic compatibility (EMC) - Part 2-4: Environment - Compatibility 
levels in power distribution systems in industrial locations for low-frequency 
conducted disturbances

 

My client would like to know if standard IEC 61000-2-4 is applicable to an 
inverter that is intended for permanent installation in a motor vehicle.  The 
inverter has no connection to a.c. mains and does not have an a.c. input power 
port.  It’s merely a 24Vdc to 230Vac/50Hz inverter.

 

I think this IEC standard is clearly out of scope for this class of equipment, 
but if client’s customer insists (a big automotive manufacturer) I’d like to be 
able craft a technical justification to waive application of the standard.

 

The standard appears only to address conducted disturbances which may be 
present on non-public (industrial) a.c. power networks and the EMC immunity of 
equipment connected to those networks.

 

Thank you,

 

 

Ralph

 


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Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal condition - Fail

[Ralph McDiarmid]

Hi Amund,

The standard I have access to, IEC 62368-1:2018 RLV © IEC 2018, has clause 
4.1.2 Use of Components.  Nowhere in that clause could I find a statement 
supporting what the lab thinks is needed.  The noun "critical component" does 
not appear anywhere in the 2018 version, but I suggest it is a synonym for the 
term "safeguard" defined and used throughout IEC 62368-1.  The lab really 
should be using language and terminology aligned with the standard being 
applied.

In other standards that do include Abnormal Condition tests, component 
temperatures are not a pass/fail criterion in that operating condition.  It 
appears to be so with IEC 62368, but it's not explicit and seems open to 
interpretation.

However, in Normal Condition at +55C ambient it looks like you've got an issue 
with at least one component.   You might need to change the upper end of your 
operating temperature range.  (55C is very high for outdoor equipment.)

Ralph

-Original Message-
From: Amund Westin  
Sent: September 4, 2024 2:56 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal 
condition - Fail

Ralph,

“The standard also does not accept that critical components get a 
temperature above what is specified in the test report for that 
component»“

The lab refer to Clause 4.1.2.
Right now, I don't have access to the standard, so I cant check the 
text.

Best ragards Amund




On 2024-09-04 09:15, Amund Westin wrote:
> Thanks all for good comments!
> 
> Ralph:
> I'm still waiting for lab feedback on this one :“ The standard also 
> does not accept that critical components get a temperature above what 
> is specified in the test report for that component». “
> I have a feeling they will reply : Annex G.5.3.3.2, even though it is 
> not a transformer, but a DC/DC module.
> I'll post the lab feedback when it comes in.
> 
> 
> John W:
> Improvement of ventilation is an option that is under discussion in the 
> R&D now. Trick to do, because of current design.
> 
> 
> We got new information yesterday and I summarize the current situation:
> 1) Abnormal condition: DCDCmodule spec +85C, measured under to be 91C 
> under abnormal condition
> 2) Normal condition: DCDCmodule spec +85C, measured to be 83C under 
> normal condition (+25C ambient)
> 3) Normal condition: DCDCmodule spec +85C, measured to be 88C under 
> normal condition (+55C ambient, spec final product is -40C to +55C))
> 
> 
> Facts:
> DCDCmodule is CB certified (-40C to +85C)
> DCDCmodule is places inside a fire enclosure
> DCDCmodule is not accessable / touchable
> Final product with DCDCmodule have been running in the field +20 years 
> without failure.
> 
> 
> I'll return with more information.
> 
> 
> Best regards Amund
> 
> 
> 
> 
> On 2024-09-03 16:52, Ralph McDiarmid wrote:
>> Perhaps Amund could ask the lab which clause in IEC 62368 supports
>> their statement, “ _The standard also does not accept that critical
>> components get a temperature above what is specified in the test
>> report for that component». “_
>> 
>> _ _
>> 
>> This is an Abnormal Condition and safeguard parameters, which include
>> rated temperature, are not subject to the same constraints imposed
>> during Normal Condition.
>> 
>> _ _
>> 
>> I suggest there are two problems here. One is that the lab seems to
>> misunderstand Abnormal Condition and the other is terminology like
>> _Basic Safeguard Parameters_ and _Supplementary Safeguard Parameters_
>> used in Figure 45 do not seem to be defined anywhere.
>> 
>> _ _
>> 
>> _Ralph_
>> 
>> From: Richard Nute 
>> Sent: Monday, September 2, 2024 12:54 PM
>> To: rmm.priv...@gmail.com; EMC-PSTC@LISTSERV.IEEE.ORG
>> Subject: RE: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 -
>> Abnormal condition - Fail
>> 
>> Further to Ralph’s comments… and with thanks to Amund…
>> 
>> Since the lab has its own interpretation of “abnormal” different
>> than that of 62368-2, the lab needs to make its position on
>> “abnormal” conditions known and apply to TC108 for consideration
>> of a change to 62368-2.
>> 
>> Or, Amund can forward the lab’s interpretation directly to TC108,
>> although this will probably go to the interpretation panel.
>> 
>> Rich
>> 
>> ps:  The lab’s response does make sense – sort of.  It is filled
>> with “what ifs” that I have some doubt that the assertions are
>> from the lab’s experience.  For example, for the exterior of the
>> module to reach 85 C, the interior has to be hotter (maybe much
>> hotter) and may exceed solid i

Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal condition - Fail

[Ralph McDiarmid]

 

From: John Woodgate  
Sent: Monday, September 2, 2024 1:10 PM
To: rmm.priv...@gmail.com
Subject: Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal 
condition - Fail

 

You may well be right, but others can reject, or fail to see, an implication. 
Maybe Rich Nute knows what the authors meant in this context.

On 2024-09-02 20:42, rmm.priv...@gmail.com   
wrote:

Sloppy wording on my part. I should have written, “The standard implies that 
safeguard parameters, like rated temperature, can be exceeded during an 
Abnormal Condition because no temperature limits are provided other than those 
in Table 38 for accessible parts.”   B.3.2  Ventilation Openings refers only to 
Table 38.

 

Ralph

 

 

From: John Woodgate    
Sent: Monday, September 2, 2024 12:17 PM
To: rmm.priv...@gmail.com  
Subject: Re: [PSES] SV: [PSES] SV: [PSES] SV: [PSES] IEC62368-1 - Abnormal 
condition - Fail

 

The 2024 edition of B.3.8 is the same, but the words below do not appear and It 
does not see easy to deduce that statement from the standard's words.

On 2024-09-02 20:04, rmm.priv...@gmail.com   
wrote:

The standard states that safeguard parameters, like rated temperature, can be 
exceeded during an abnormal test.

-- 
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying

 


 

 

Virus-free. 

 www.avg.com

 

-- 
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying

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Re: [PSES] [PSES] IEC62368-1 - Abnormal condition - Fail

[Ralph McDiarmid]

Yes, of course, but the SOD (standards development organizations) like UL, 
ANSI, CSA, and IEC, work closely with the manufacturer of those components to 
establish useful limits.  As John points out, a temperature limit to the 
closest 5 Celsius degrees is likely the smallest, practicable step-size and fit 
for purpose.

 

Ralph

 

 

From: sudhakar wasnik  
Sent: Thursday, August 29, 2024 2:07 PM
To: rmm.priv...@gmail.com
Cc: EMC-PSTC 
Subject: Re: [PSES] [PSES] IEC62368-1 - Abnormal condition - Fail

 

Agencies like UL, CSA, TUV etc….  aren’t the agencies responsible for approving 
components like capacitors, switches, cables , transformers , fuses etc?

 

>From the component manufacturer’s point of view, parameters have tolerances 
>like temperature, If it’s data sheet has tolerance in terms of % or values , 
>It can be explained to certification agencies.

 

This is quite common usually with power supply manufacturers… .claims all 
certifications, however when it is installed in end products…   the same power 
supply may have different thermal outcome

And this will have to be resolved by end user under normal , abnormal, single 
fault conditions … 

 

Hope this helps, 

 

Sudhakar 





On Aug 29, 2024, at 1:24 PM, Ralph McDiarmid mailto:rmm.priv...@gmail.com> > wrote:

 

“approved” by whom, the manufacturer ?   They would be better able to determine 
that limit and it would be based on reliability analysis.

 

The 5-degree increment is an interesting point, whoever, just about any 
component you choose seems to have a temperature limit that is a multiple of 5 
degrees C.   (circuit boards, transistors, electrolytic capacitors, insulated 
wire, recognized insulation systems).  Everything rounded to the closest 5 
degrees perhaps.

 

Ralph

 

From: Richard Nute mailto:ri...@ieee.org> > 
Sent: Thursday, August 29, 2024 12:17 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] SV: [PSES] IEC62368-1 - Abnormal condition - Fail

 

 

 

Hi John:

 

I disagree.  We don’t know the temperature for failure.  We don’t know the 
difference between the “approved” temperature and the failure temperature.  
Indeed, we seldom test for failure temperature.  

 

All we can say is that at 85 C, the part should work for the product lifetime.  
Above this temperature, the part may work for the product lifetime, or it may 
fail before the product lifetime.  Ideally, the end product should be like the 
“one-hoss shay.”

https://www.youtube.com/watch?v=wiOHhhwnK6k

 

And, the “approved” temperature is 85 C, which is an arbitrary assignment.  If 
it was not arbitrary, I would have expected the “approved” temperature to be 
83, 84, or 86 or some number other than 5 degree increments. 

 

😊

 

Best regards,

Rich  

 

 

From: John Woodgate mailto:j...@woodjohn.uk> > 
Sent: Thursday, August 29, 2024 11:35 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] SV: [PSES] IEC62368-1 - Abnormal condition - Fail

 

But that component is not likely to be very reliable, if its temperature under 
normal conditions is close to the maximum permitted.

On 2024-08-29 19:04, Amund Westin wrote:

Thanks James,

 

No, the component that gets hot, but it is not accessible. It’s on a pcb inside 
the metal enclosure. The temperature was measures to 87C. The CB test report 
for the DC/DC component says it was tested and approved up to 85C.

No ignition. The FAIL statement was due to higher temperature than approved in 
CB report for the component.

 

Best regards Amund

 

 

Fra: James Pawson (U3C) 
Sendt: 29. august 2024 18:35
Til: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Emne: Re: [PSES] IEC62368-1 - Abnormal condition - Fail

 

Amund,

 

Is the temperature accessible?

Is there any ignition caused?

 

If no then the requirements have likely been met.

 

All the best

James

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy

 

 <http://www.unit3compliance.co.uk/> www.unit3compliance.co.uk |  
<mailto:ja...@unit3compliance.co.uk> ja...@unit3compliance.co.uk

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

Office hours:

Every morning my full attention is on consultancy, testing, and troubleshooting 
activities for our customers’ projects. I’m available/contactable between 1300h 
to 1730h Mon/Tue/Thurs/Fri.

For inquiries, bookings, and testing updates please send us an email on 
he...@unit3compliance.co.uk <mailto:he...@unit3compliance.co.uk>  or call 01274 
911747. Our lead times for testing and consultancy are typically 4-5 weeks.

 

 

 

 

From: Charlie Blackham mailto:char...@sulisconsultants.com> > 
Sent: 29 August 2024 17:1

Re: [PSES] NFPA cybersecurity "shall be permitted"?

[Ralph McDiarmid]

Quite so and thank you John.

 

The scope of this standard appears to be, “NFPA 79 provides safeguards for 
industrial machinery to protect operators, equipment, facilities, and 
work-in-progress from fire and electrical hazards.”   

 

Perhaps Cybersecurity belongs in a separate publication.

 

Ralph

 

From: John Woodgate  
Sent: Friday, August 23, 2024 2:53 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NFPA cybersecurity "shall be permitted"?

 

'Shall' ought to have been changed to 'should'.

On 2024-08-23 22:45, Scott Aldous wrote:

Hi Lauren, 

 

Digging a bit, it looks like this was originally proposed as a hard 
requirement. See PI 22 in this doc 
<https://docinfofiles.nfpa.org/files/AboutTheCodes/79/79_F2023_EEI_AAA_FD_PIResponses.pdf>
  (you can search on "cybersecurity" to find it). This was proposed by Keith 
Waters from Schneider Electric, and at the time included "shall" rather than 
"shall be permitted".The committee statement was that "the proposed language is 
overly broad and restrictive."

 

If you search on "cybersecurity" in this doc 
<https://docinfofiles.nfpa.org/files/AboutTheCodes/79/79_F2023_EEI_AAA_SD_PCResponses.pdf>
 , you can find a subsequent public comment where the same submitter revised 
the proposal, this time modifying the language that would have made it 
mandatory. The submitter's comment there states:

 

"In reviewing the response to the original PI, I still feel that cybersecurity 
is essential to properly protecting industrial machinery and a consensus 
standard is the best way to protect these systems in lieu of 51 different 
requirements from the federal government and the individual states. However, I 
understand that we need to create a starting point to learn the best methods 
before setting full requirements. The change to the PI to make the requirement 
“shall be permitted” vs “shall” is a good first step into creating the safety 
and reliability protections."

 

Even though this second comment was rejected, it references a subsequent 
revision with much the same language that can be found here 
<https://docinfofiles.nfpa.org/files/AboutTheCodes/79/79_F2023_EEI_AAA_SD_SRStatements.pdf>
 .

 

On Fri, Aug 23, 2024 at 2:20 PM Ralph McDiarmid mailto:rmm.priv...@gmail.com> > wrote:

Sounds optional to me too.  You’re allowed to do it, but you’re not required to 
do it.

 

It’s Friday in Canada and Mexico too, but the way;>)

 

 

Ralph

 

 

From: Lauren Crane <1afd08519f18-dmarc-requ...@listserv.ieee.org 
<mailto:1afd08519f18-dmarc-requ...@listserv.ieee.org> > 
Sent: Friday, August 23, 2024 1:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] NFPA cybersecurity "shall be permitted"?

 

Hello All, 

 

Happy Friday (US)….

 

There is a new section in NFPA 79 - 2024 edition – “4.10 Cybersecurity.  
Industrial machinery that is connected to a communication network and permitted 
to control any part of the machinery shall be permitted to comply with the 
following: (1) A cybersecurity assessment conducted on the connected system to 
determine vulnerabilities to cyberattacks; (2) A cybersecurity commissioning 
certification conducted on the connected system to ensure it is designed 
against cyberattacks and known vulnerabilities; (3) Documentation of the 
assessment and certification provided to those authorized to inspect, operate, 
and maintain the system”

 

My best take at this is the whole thing is optional given the underlined “shall 
be permitted”. That phrase seems to mean (as it is used throughout NFPA 79) “is 
allowed”.  But if I read it that way, it means the whole section 4.10 was added 
just to say one is allowed to do 3 things and it has no obligation to actually 
do anything, which seems off - because it is rather silly – Particularly since 
doing what is listed would not reasonably be questioned, so it doesn’t really 
need to be clarified that one is allowed to do it. 

 

Do any of you have a different take on this?

 

Best Regards, 

-Lauren

 


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Re: [PSES] NFPA cybersecurity "shall be permitted"?

[Ralph McDiarmid]

Sounds optional to me too.  You're allowed to do it, but you're not required
to do it.

 

It's Friday in Canada and Mexico too, but the way;>)

 

 

Ralph

 

 

From: Lauren Crane <1afd08519f18-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, August 23, 2024 1:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] NFPA cybersecurity "shall be permitted"?

 

Hello All, 

 

Happy Friday (US)..

 

There is a new section in NFPA 79 - 2024 edition - "4.10 Cybersecurity.
Industrial machinery that is connected to a communication network and
permitted to control any part of the machinery shall be permitted to comply
with the following: (1) A cybersecurity assessment conducted on the
connected system to determine vulnerabilities to cyberattacks; (2) A
cybersecurity commissioning certification conducted on the connected system
to ensure it is designed against cyberattacks and known vulnerabilities; (3)
Documentation of the assessment and certification provided to those
authorized to inspect, operate, and maintain the system"

 

My best take at this is the whole thing is optional given the underlined
"shall be permitted". That phrase seems to mean (as it is used throughout
NFPA 79) "is allowed".  But if I read it that way, it means the whole
section 4.10 was added just to say one is allowed to do 3 things and it has
no obligation to actually do anything, which seems off - because it is
rather silly - Particularly since doing what is listed would not reasonably
be questioned, so it doesn't really need to be clarified that one is allowed
to do it. 

 

Do any of you have a different take on this?

 

Best Regards, 

-Lauren

 


LAM RESEARCH CONFIDENTIALITY NOTICE: This e-mail transmission, and any
documents, files, or previous e-mail messages attached to it, (collectively,
"E-mail Transmission") may be subject to one or more of the following based
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contained in or attached to this message is STRICTLY PROHIBITED. If you have
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Re: [PSES] Burden test

[Ralph McDiarmid]

Volt-amperes (VA) would be sufficient since active power (W) cannot be greater 
than VA.  (recall the power triangle)

I’d rather use “power” not “active power”, since “active” doesn’t add anything 
to the definition of that term.

 

I would avoid ambiguity such as, “…ports of significant burden  “

 

And, 125 V is a poor example because it is not a nominal voltage in North 
America.  It’s 120 V or 120/240 V or 120/208 V – those are common nominal 
values found in low-voltage distribution for residential and commercial 
buildings in North America.

 

 

Ralph

 

From: Boštjan Glavič  
Sent: Thursday, August 22, 2024 9:51 PM
To: 'rmm.priv...@gmail.com' ; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] Burden test

 

Thank you all. I decided to contact TC57 which prepared this standard and let’s 
see.

 

When I went once more through standard, I think it is really like apparent 
power. So it shall be equal to power consumption of power supply under normal 
load.

 

Below extract from standard – clauses with word Burden.

 

Best regards,

Boštjan

 

5.4 Rated burden

The burden for the power supply (a.c. including power factor/d.c.) at quiescent 
state and

maximum load.

The maximum start-up inrush current of the power supply circuits shall also be 
stated.

 

 

 

6.1.3 Auxiliary supplies, I/O

6.1.3.1 General requirements for marking

For marking the following should be taken into account:

• a.c. – with symbol 2 of Table 3 and rated frequency or frequency range;

• d.c. – with symbol 1 of Table 3;

• symbol 3 of Table 3 on equipment for a.c. and d.c. supply;

• a hyphen (-) shall be used to separate the lower and upper nominal voltages, 
for example,

125 V-230 V;

• the burden in watts (active power) or volt-amperes (apparent power) or the 
rated input

current, with all accessories or plug-in modules connected.

The documentation shall specify the burden of individual digital inputs, output 
relays and

other I/O ports of significant burden in order for the user to calculate the 
worst-case

burden for the equipment application.

The values shall be measured with the equipment powered at nominal voltage, but 
not be

operational.

The measured value shall not exceed the marked value by more than 10 %;

 

 

6.1.3.2 Auxiliary supply

The following information shall be provided on the equipment and in the 
documentation:

• a.c. and/or d.c. supply;

• the rated values.

• in the documentation:

• the burden.

6.1.3.3 Inputs

The following information shall be provided in the documentation:

• a.c. and/or d.c. supply;

• the rated values;

• burden on the supply input.

 

6.1.3.4 Outputs

The following information shall be provided in the documentation:

• the kind of output, for example, relay, optocoupler etc;

• burden on the supply input;

• the switching capability on/off;

• the switching voltage;

• the permissible current, continuous value and short time value for 1 s;

• withstand voltage across open contacts.

Compliance with 6.1.3.1 to 6.1.3.4 is checked by inspection or by measurement.

 

6.8 Burden test

Burden 6.8.1 for AC power supply

6.8.1.1 Typical load condition

The equipment is powered at rated auxiliary energizing voltage with typical 
load of all input

and outputs. The test shall be carried out by voltamperes (VA) measurement. The 
maximum

value of 5 consecutive tests shall be used for burden claim.

6.8.1.2 Inrush current and power-up duration

The equipment is switched on at rated auxiliary energizing voltage. The peak 
value of input

current during power-up, the duration from switching instant to the instant 
that input current

gets to within 10 % of quiescent state current shall be recorded. The maximum 
value of

5 consecutive tests shall be used for inrush current and power-up duration 
claim.

From: Ralph McDiarmid mailto:rmm.priv...@gmail.com> > 
Sent: Thursday, August 22, 2024 9:23 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Burden test

 


CAUTION: This email originated from outside of our organisation. Do not click 
links or open attachments unless you recognise the sender and know the content 
is safe.

 

I agree with John’s comment.  I will add that standard writing panels 
(committees) should use their vocabulary with intelligence.  Any ambiguous 
terms should be defined somewhere in part one of IEC 61850.  I don’t have a 
copy, and the IEC preview doesn’t help.

 

I will hazard a guess that in this context, the adjective “intelligent” means a 
power supply that is able to communication over a network for the exchange of 
data and for remote control or configuration.

 

Ralph

 

From: John Woodgate mailto:j...@woodjohn.uk> > 
Sent: Thursday, August 22, 2024 10:41 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] Burden test

 

I think you are required to state the power consumption of every port that 
consumes power. If your 

Re: [PSES] Burden test

[Ralph McDiarmid]

I agree with John’s comment.  I will add that standard writing panels 
(committees) should use their vocabulary with intelligence.  Any ambiguous 
terms should be defined somewhere in part one of IEC 61850.  I don’t have a 
copy, and the IEC preview doesn’t help.

 

I will hazard a guess that in this context, the adjective “intelligent” means a 
power supply that is able to communication over a network for the exchange of 
data and for remote control or configuration.

 

Ralph

 

From: John Woodgate  
Sent: Thursday, August 22, 2024 10:41 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Burden test

 

I think you are required to state the power consumption of every port that 
consumes power. If your SMPS really is 'intelligent', then the standard 
applies. But I wonder what the relevant definition of 'intelligent' is. There 
appears to be no method of measurement for IQ!

On 2024-08-22 17:53, Richard Nute wrote:

 

Hi Bostjan:

 

While this does not answer your specific questions, it may be helpful:

 

https://en.wikipedia.org/wiki/IEC_61850

 

Good luck, and best regards,

Rich

 

 

From: Boštjan Glavič   
<2b8ba113ae76-dmarc-requ...@listserv.ieee.org> 
Sent: Thursday, August 22, 2024 4:32 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] Burden test

 

Dear all,

 

Is anyone familiar with burden test according IEC 61850-3 standard? Is this 
test applicable for switch mode  power supply with AC input and DC output?

 

How to conduct the test? What is the idea of the test?

 

Standard is not really clear.

 

Thank you for your support.

 

Best regards,

Bostjan

 

 


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Best Wishes
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Keep trying

 


 

 

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Re: [PSES] Motor Locked Rotor and Overload Testing

[Ralph McDiarmid]

That’s the only non-linear effect I can envision, however, all the models I’ve 
seen using a Google search suggest an RL network only.  I don’t think the 
stator laminations would saturate during locked rotor for the same reason a 
transformer core doesn’t saturation when its secondary winding is shorted.

 

Ralph

 

From: James Pawson (U3C)  
Sent: Thursday, August 15, 2024 4:53 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Motor Locked Rotor and Overload Testing

 

Hi John,

 

Thanks for the reply. Non linear response because of saturation of the magnetic 
material?

 

All the best

James

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy

 

  www.unit3compliance.co.uk |  
 ja...@unit3compliance.co.uk 

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

Office hours:

Every morning my full attention is on consultancy, testing, and troubleshooting 
activities for our customers’ projects. I’m available/contactable between 1300h 
to 1730h Mon/Tue/Thurs/Fri.

For inquiries, bookings, and testing updates please send us an email on 
he...@unit3compliance.co.uk   or call 01274 
911747. Our lead times for testing and consultancy are typically 4-5 weeks.

 

 

 

 

From: John Woodgate mailto:j...@woodjohn.uk> > 
Sent: Wednesday, August 14, 2024 5:46 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] Motor Locked Rotor and Overload Testing

 

The stalled motor is a non-linear load, so an RL circuit might not be 
representative. For overload testing, we used a band-brake, but I suppose a 
disc brake would be used now. You would need to plot the torque versus 
hydraulic pressure curve to calibrate it.

On 2024-08-14 17:36, James Pawson (U3C) wrote:

Hi all,

 

We’ve had a few things in the lab recently requiring motor locked rotor and 
motor overload testing.

 

Working on the principle that a locked rotor motor looks like a short circuit 
(inductance and DC resistance of winding) would it be reasonable to just 
substitute the motor with the equivalent circuit?

 

For an overload testing (steadily increasing the load on the motor drive until 
failure or trip) I’m not sure how best to practically do this. How do people 
achieve these tests practically in the lab? What equipment is used?

 

Any recommendations gratefully received.

 

All the best

James

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy

 

  www.unit3compliance.co.uk |  
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-- 
OOO - Own Opinions

Re: [PSES] Fault Exclusion

[Ralph McDiarmid]

If I understand your question correctly, then a failure of a control wire would 
result in the loss of two, independent safety functions, each function being 
provided by a separate component.  That would result in a loss of single-fault 
tolerance, a central principle of product safety.  IEC62368-1 is a good, modern 
reference.  The principles of product safety described in the old IEC60950-1 is 
another.

 

To determine if the loss of two independent safety functions in your equipment 
results in a hazard, then you likely need to do an FMEA (Failure Mode & Effects 
Analysis).

 

Ralph

 

From: Steve Brody <355150a0f9b9-dmarc-requ...@listserv.ieee.org> 
Sent: Thursday, August 8, 2024 8:58 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Fault Exclusion

 

Experts: 

  

I have been told that: 

  

'if you have two safety components in the same electrical cabinet you can 
connect them with a single control wire, you can exclude faults against that 
wire as a fault that needs to be considered for safety calculations.' 

  

It is logical if the two safety components' are redundant.  But if they have 
different functions? 

  

I have not been able to confirm that in any standard. 

  

If you agree that this statement is correct, then I would appreciate your 
rationale and if possible a reference to chapter and verse in a standard or 
risk assessment document. 

  

Thanks, 

  

Steve Brody 

sgbr...@comcast.net   

C - 603 617 9116 

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Re: [PSES] CAN/CSA C22.2 No. 62133-2:20 for CR 2032 Batteries?

[Ralph McDiarmid]

Unless Amazon has a regulatory department that has access to national
standards, this may be a simple checkbox for in-coming inspection.  In that
case, you might be stuck with the requirement regardless of CR2032 cell
type.  

 

CAN/CSA C22.2 are part 2 national standards for Canada, not applicable in
other countries unless adopted.

 

Ralph

 

From: Ted Eckert <07cf6ebeab9d-dmarc-requ...@listserv.ieee.org> 
Sent: Monday, July 22, 2024 11:21 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] CAN/CSA C22.2 No. 62133-2:20 for CR 2032 Batteries?

 

Hello John,

 

I believe that IEC 60086-4 is the applicable standard for primary
(non-rechargeable) lithium batteries, including coin cells. As others have
noted, IEC 62133-2 is for secondary (rechargeable) batteries.

 

Ted Eckert

The opinions expressed in this message are my own and do not necessarily
reflect those of my employer.

  _  

From: John Riutta mailto:jriu...@celestron.com> >
Sent: Monday, July 22, 2024 10:31 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>
mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >
Subject: [EXTERNAL] [PSES] CAN/CSA C22.2 No. 62133-2:20 for CR 2032
Batteries? 

 


You don't often get email from jriu...@celestron.com
<mailto:jriu...@celestron.com> . Learn why this is important
<https://aka.ms/LearnAboutSenderIdentification> 



Hello all,

 

We've been seeing Amazon requiring CAN/CSA C22.2 No. 62133-2:20 for all
products that use or contain at time of sale a CR 2032 coin cell battery. I
was of the understanding that this standard did not apply to this battery.
Unfortunately, I do not possess a copy of the standard so I cannot verify
this myself. MayI ask if anyone here can offer verification or rebuttal
please?

 

Best regards,

John

 

John E. Riutta, MA, MBA, FLS I Product Development and Product Compliance
Manager I  <mailto:jriu...@celestron.com> jriu...@celestron.com I
323.446.1076 

CELESTRON, LLC. I 2835 Columbia Street I Torrance, CA 90503

 

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u-ovu97c5RZhLW5JAVauCDQwYc3UQ&s=mp6OgNq_McWjXY2YQYjZ9Dk6_XzP1VPvIEe8C8zj56A&
e=>
<https://urldefense.proofpoint.com/v2/url?u=https-3A__twitter.com_Celestron&;
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5JAVauCDQwYc3UQ&s=VPySibohtehHWHpC8d5rHDIovgyX-KLLxjtWSiblJGI&e=>
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RZhLW5JAVauCDQwYc3UQ&s=mFMWx391BWGOZRSQd2VOWpQ8frezSjy2nYeDDPQcxtg&e=>
<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.youtube.com_user_C
elestronDotCom&d=DwMFaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=x40q
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Iu-ovu97c5RZhLW5JAVauCDQwYc3UQ&s=ziJj_dfd_78luGSUUH4AfwmPyhD40fdDd46c8oL7bcc
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ADpQfIk&e=> 

 

From: Ralph McDiarmid mailto:rmm.priv...@gmail.com>
> 
Sent: Friday, July 19, 2024 10:40 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] "Intelligent" Power Modules?

 

I stopped reading at the word "performances".  

 

 

Ralph

 

From: Douglas Powell mailto:doug...@gmail.com> > 
Sent: Friday, July 19, 2024 9:27 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] "Intelligent" Power Modules?

 

So I just finished reading "1.2 kV/400 A SiC Source Turn-Off MOSFET
Intelligent Power Module" (https://ieeexplore.ieee.org/document/10574416
<https://urldefense.proofpoint.com/v2/url?u=https-3A__ieeexplore.ieee.org_do
cument_10574416&d=DwMFaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=x40
qV4DM3u4JrqHl_FVpxdOqkHDBo3f6BvwvAwIWGH8&m=a2CCo_J4V1NasdwIBe0EeqpUJTYCY_V6T
mg345FDzau0JquoopInoKrPLEhikCaN&s=_UxHI-pyQoHSCbqUQCVFvIEGK_7RUdJisvq72DPJL8
w&e=> )

 

The word "intelligent" in the title of the article piqued my interest.  So,
what's with the overuse of the term "intelligent" nowadays?  Whe

Re: [PSES] "Intelligent" Power Modules?

[Ralph McDiarmid]

I stopped reading at the word “performances”.  

 

 

Ralph

 

From: Douglas Powell  
Sent: Friday, July 19, 2024 9:27 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] "Intelligent" Power Modules?

 

So I just finished reading "1.2 kV/400 A SiC Source Turn-Off MOSFET Intelligent 
Power Module" (https://ieeexplore.ieee.org/document/10574416)

 

The word "intelligent" in the title of the article piqued my interest.  So, 
what's with the overuse of the term "intelligent" nowadays?  When I read the 
article, I noticed that the word appeared only three times: once in the title, 
once in the abstract, and once in the opening paragraph. The acronym "IPM" 
appeared 31 times throughout.  I saw no mention of any aspects of operational 
intelligence used in the design of this power module.  Is there something I 
missed, or is the term "Intelligence" being used as marketing hype?

I'm seriously experiencing some fatigue over all this talk of Intelligence, 
Machine Intelligence, and Artificial Intelligence.  

 

Thanks for letting me air out a little,  ~Doug

 

 

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Re: [PSES] Using Red Phosphorous ferrite core on a 48VDC motor

[Ralph McDiarmid]

I doubt ferrite cores are flammable, but if they are, I’m sure they are 
superior to the rating UL94V-0.  

 

 

From: Chris <0133def26cf0-dmarc-requ...@listserv.ieee.org> 
Sent: Wednesday, July 10, 2024 10:40 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Using Red Phosphorous ferrite core on a 48VDC motor

 

Folks,

 

I need some help to answer this product safety question.

 

We are using ferrite core T60006-L2025-W380 to supress radiated emissions on 
the 48VDC motor cable.

 

I am concerned about the flamilibility of the Red Phosphorus which is contained 
in the Ferrite core.

 

Any help is appreceiated 

 

 

Christopher

Nextracker LLC.

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Re: [PSES] Switching power supplies continued

[Ralph McDiarmid]

RF radiated emission measurements are not precious and it’s not unusual to find 
a +/- 5dB variation between two certified open-area test sites.  (a combination 
of equipment calibration variance and test site tolerances)

 

It is possible then to find a pass when testing at one site and receive a 
failure when testing at another.  I think this has been the experience for some 
and likely something that has existed for decades in the industry and is 
accepted as the “norm”.

 

Ralph

 

From: Elliott Martinson <33e8876b9475-dmarc-requ...@listserv.ieee.org> 
Sent: Wednesday, July 10, 2024 7:56 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Switching power supplies continued

 

On one hand, it’s odd they can even claim “compliance”, when their SMPS module 
will interact with customer design so much.

 

On the other hand, I have experience with a supply like this, where I had to 
prove it still failed class B emissions with literally nothing on its output 
but a purely resistive load (small loop area, conductive surface area – other 
than pseudo-“cables”)

 

From: Matthew Wilson | GBE mailto:matthew.wil...@gbelectronics.com> > 
Sent: Monday, July 8, 2024 11:28 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] Switching power supplies continued

 


You don't often get email from matthew.wil...@gbelectronics.com 
 . Learn why this is important 
 



That is an interesting consideration regards the beat frequency, thanks for the 
post.  Something we have noticed several times with third-party ‘bought in’ 
mains-DC SMPSU (most people do that rather than design a bespoke one because 
the third-party has gained the necessary re safety compliance) is that people 
may specify the SMPSU for the maximum load out of their power budget for the 
apparatus to be driven by the SMPSU. 

 

This usually is a sum/concatenation of all the highest current draw 
circuits/parts e.g. all LEDs on, activating sounder transducer, maybe driving a 
printer (usually thermal), radio module (Wi-Fi say) active, etc, etc.

 

In fact the equipment does not do this ‘maximum draw’ too often and so the 
majority of the time the SMPSU is usually operating at lower capacity (a few 
LEDs on, idle printer, not actively TX/RX data packets).  And it is then that 
EMC emissions created by the SMPSU (radiated and conducted) are actually at 
their worse.  In some (probably more extreme) cases this can upset performance 
of the apparatus, or even co-located equipment, but also it can annoy when at 
the EMC test chamber with breaches of the emissions limit line.

 

The downside of third-party power supplies is although they will have a nice 
declaration of conformity (for us in the EU (OK I know UK isn’t any more but 
we’ve decided to carry on with it behind the scenes!) and claims for EMC 
compliance, never is any precise detail of how and the environment in which 
these tests were performed provided.  A resistive load on the shortest possible 
DC output leads, with short mains input leads too I’m sure is the setup – happy 
to be proved wrong!

 

Nearest I’ve found to such is this from Meanwell but it has some assumptions – 
large metal plates for one (but which one did they use for a particular 
model?!):

 

https://www.meanwell.co.uk/knowledge-base/how-do-mean-well-test-for-electro-magnetic-interference-emi

 

Anyway, as is probably known in this audience, but is a constant reminder to 
clients and so forth, you can’t expect not to test a third party SMPSU even 
when it is ‘compliant’.

 

Thanks for giving me an excuse to ramble on :-)

 

Kind regards,

 

Matthew Wilson,

GB Electronics (UK) Ltd.

 







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From: doug emcesd.com mailto:d...@emcesd.com> > 
Sent: Wednesday, July 3, 2024 10:55 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] Switching power supplies continued

 

Hi All,

 

When thinking about power supplies, one would think that they either work or 
not. But this is not the case.

 

Switching power supply frequencies are usually much lower that today’s system 
frequencies. This leads to a situation where it can take an hour or much more 
for an edge to hit a circuit in the system at a critical

Re: [PSES] Switching power supplies continued

[Ralph McDiarmid]

Further to John’s comment, here is an extract from EMC standard CISPR 22:

 

“The operational conditions of the EUT shall be determined by the manufacturer 
according to

the typical use of the EUT with respect to the expected highest level of 
emission. The

determined operational mode and the rationale for the conditions shall be 
stated in the test

report.”

 

The operating condition producing the highest level of emission may not be the 
rated output power of the EUT.  The manufacturer is expected to investigate.

 

Ralph

 

From: John Woodgate  
Sent: Monday, July 8, 2024 9:42 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Switching power supplies continued

 

The DoC states the standards applied, and those standards (CISPR-originated) 
give very precise details of the test set-up.

On 2024-07-08 17:27, Matthew Wilson | GBE wrote:

The downside of third-party power supplies is although they will have a nice 
declaration of conformity (for us in the EU (OK I know UK isn’t any more but 
we’ve decided to carry on with it behind the scenes!) and claims for EMC 
compliance, never is any precise detail of how and the environment in which 
these tests were performed provided.  A resistive load on the shortest possible 
DC output leads, with short mains input leads too I’m sure is the setup – happy 
to be proved wrong!

-- 
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying

 


 

 

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Re: [PSES] power supplies - standardized performance tests

[Ralph McDiarmid]

IEC 61204-6 does look promising, but it does have a limit on output voltage of 
200 volts d.c.   I’ll assume like its power limit of 2,500 watts, its voltage 
limit can be extended by applying good engineering principles.

 

And it seems reasonably priced.

 

Thanks for finding this John.

 

Ralph

 

 

From: John Woodgate  
Sent: Tuesday, July 2, 2024 2:17 PM
To: rmm.priv...@gmail.com
Subject: Re: [PSES] power lsupply musings #1

 

IEC doesn't look too promising. These are not exactly on stone tablets, but 
they are old: IEC61204:1993 + AMD1:2001, IEC 61204-6: 2000. You can preview 
them. go to www.iec.ch <http://www.iec.ch> , then go to Web store and search.

On 2024-07-02 20:01, Ralph McDiarmid wrote:

Oh boy, have I seen this, in the distant past.  Today, there is likely an IEC 
standard which defines how this measurement should be performed.

 

When I was a development engineer at a small d.c. power supply company in the 
1990s we grappled with this same issue.  We eventually designed a custom 
voltage probe which measured differential ripple & noise into 50 ohms with a 20 
MHz bandwidth.  It provided a repeatable measurement of output noise into a 
stabilized impedance while rejecting common-mode contribution.  Its 
implementation settled most arguments on how this measurement was done since 
some customers at the time were challenging our results when we were merely 
using an unbalanced 10X scope probe with any convenient oscilloscope on hand.  

 

Any, well considered, implementation for a noise probe is probably just as good 
so long as it is used consistently, and the method disclosed to those who need 
to know.  

 

Ralph

 

From: doug emcesd.com  <mailto:d...@emcesd.com>  
Sent: Monday, July 1, 2024 4:18 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] power lsupply musings #1

 

Hi Everyone,

 

I thought I would post a bit about power supplies. Something as simple as 
trying to measure ripple on the output can be very inaccurate, overstating 
ripple amplitude by a lot, 100% over stated is not all that unusual.

 

One problem arises from common mode noise on the output that gets into the 
structure of the probe used for the measurement. Most probes have modes 
resulting in display of voltages that are not actually present. If you doubt 
this, just connect both terminals of a scope probe to the low end, say ground, 
of a power supply output and you will often see a significant signal that is 
not actually there. Whatever one measures with a shorted probe on the ground 
side of the supply output is the error in the measurement and can easily exceed 
the actual ripple voltage present on the output.

 

Have you seen this? I cover this in detail in my presentations.

 

Doug

  
<https://lh4.googleusercontent.com/_HuR3Ky2TF_XhFHyxnYRmiq7nHQldnMsPNYFaLG6kb5T4y8MeCe-BDC_BscJtSFgszSSjssihHS-pjM3-jwNP8S0CwE-gN8fsRsPkojiAlmpBwb20vIVizS-siCUywW_jqrefbVr>
 


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Re: [PSES] dielectric strength question -- update

[Ralph McDiarmid]

I'm aware of IEC 60664-1 (insulation coordination) and I've referenced it
many times over the years.  You'll find its normative reference in several
IEC and CSA standards and UL840 seems to rely on its database.  IEC 60664
has been around a long time and has several parts.

 

Ralph

 

From: Richard Nute  
Sent: Friday, June 28, 2024 3:31 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] dielectric strength question -- update

 

 

Since my 23 June message, I may have found the answer to my quest as to
where the air insulation (clearances) distances came from: IEC 664, Edition
1, 1980,  Appendix Table AI, withstand voltages, and Table AII, breakdown
voltages. 

According to IEC 664, Table AII is "experimental data" by 

Prof. Dr. Ing. W. Pfeiffer, convenor of IEC TC109/MT3, elektrotechnische
zeitschrift  Ausg. B, 1976. 

Dr. Hermstein, elektrotechnische zeitschrift  Ausg. A, 1969.  

These are German electrotechnical journals issue A, 1969, and issue B, 1976.
I could not find copies of these.  Perhaps our German subscribers can find
these.

I surmise from the tables that these two people tested air breakdown voltage
as a function of distance.  I did find that Dr. Hermstein did some
experimental work on electrical performance of gasses that has been
discredited. 

Table AI (IEC 664) is withstand voltages based on the breakdown voltages in
Table AII (IEC 664).  This is the source of IEC 60664-1 clearance distance
tables which have been used by a number of IEC standards committees.  

I've attached a plot of both the breakdown voltage per distance and the
withstand voltage per distance through air.  These are linear axes while the
IEC 664 and IEC 60664-1 plots are logarithmic axes.  I've included trend
lines (dotted) and their equations.  (The voltage-distance tables are not in
IEC 60664-1.)  

I suspect the non-linearity of the breakdown (red) line is due to
measurement problems. I would expect the line to be straight except for the
small dimensions that approach the Paschen voltage limit for air, 327 volts
peak.  (Paschen studied gas breakdowns at very small gaps and found that
various gasses do not break down at very small gap dimensions.) 

Best regards,

Rich

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Re: [PSES] power lsupply musings #1

[Ralph McDiarmid]

Oh boy, have I seen this, in the distant past.  Today, there is likely an
IEC standard which defines how this measurement should be performed.

 

When I was a development engineer at a small d.c. power supply company in
the 1990s we grappled with this same issue.  We eventually designed a custom
voltage probe which measured differential ripple & noise into 50 ohms with a
20 MHz bandwidth.  It provided a repeatable measurement of output noise into
a stabilized impedance while rejecting common-mode contribution.  Its
implementation settled most arguments on how this measurement was done since
some customers at the time were challenging our results when we were merely
using an unbalanced 10X scope probe with any convenient oscilloscope on
hand.  

 

Any, well considered, implementation for a noise probe is probably just as
good so long as it is used consistently, and the method disclosed to those
who need to know.  

 

Ralph

 

From: doug emcesd.com  
Sent: Monday, July 1, 2024 4:18 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] power lsupply musings #1

 

Hi Everyone,

 

I thought I would post a bit about power supplies. Something as simple as
trying to measure ripple on the output can be very inaccurate, overstating
ripple amplitude by a lot, 100% over stated is not all that unusual.

 

One problem arises from common mode noise on the output that gets into the
structure of the probe used for the measurement. Most probes have modes
resulting in display of voltages that are not actually present. If you doubt
this, just connect both terminals of a scope probe to the low end, say
ground, of a power supply output and you will often see a significant signal
that is not actually there. Whatever one measures with a shorted probe on
the ground side of the supply output is the error in the measurement and can
easily exceed the actual ripple voltage present on the output.

 

Have you seen this? I cover this in detail in my presentations.

 

Doug

 
 

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Re: [PSES] Polyimide film/tape for fire enclosure (UL 94 V-0 rating)

[Ralph McDiarmid]

Generally, adhesive tape cannot be relied on for a safety feature, like forming 
part of a fire enclosure.  Standards typically require mechanical securement.

 

Ralph

 

From: James Pawson (U3C)  
Sent: Sunday, June 30, 2024 9:51 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Polyimide film/tape for fire enclosure (UL 94 V-0 rating)

 

Hello safety experts,

 

In relation to my post a month or so ago about battery fire enclosures w.r.t. 
EN 62368-1 I wondered about using polyimide tape to provide a fire enclosure 
for a battery. The idea being to wrap the tape around the battery, at least 
once, probably twice.

 

Suitable materials could include:

 

*   DuPont Kapton 

  (UL file E39505) states V-0 for 25um thick
*   Muller Alhorn Norton TH 

  (UL file E231847  ) states 
V-0 for 25um thick

 

Tapes vs film

 

Plastic material is tested to UL 94 but tapes are tested to UL 510. Therefore, 
as soon as you put a self adhesive backing on a UL 94 V-0 rated film, even if 
the material doesn’t change, the material now needs testing to UL 510. As far 
as I can tell, the test methodology between the two standards are not 
comparable.

 

I feel like there is no reason that adding a small amount of adhesive on the 
back would significantly change the flammability characteristics.

 

The alternative “by the book” method would be to wrap the battery in the 
polyimide film and secure with some regular polyimide tape on the outside 😊

 

Vertical Burning vs Thin Material Vertical Burning

 

The tests appear to be fundamentally similar in terms of sample size and flame 
power, just the wrapping of the thin material sample around a supporting 
mandrel.

 

It looks like V-0 and VTM-0 ratings are comparable in this respect.

 

As always, I would appreciate your thoughts on the matter, particularly in 
pointing out any problems in logic or understanding on my part.

 

References

UL 94

UL 510

This link also discusses some of the same  

 

 

(If only we had a vertical burning test rig and we could try out some of these 
ideas…)

 

All the best

James

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : Consultancy

 

  www.unit3compliance.co.uk |  
 ja...@unit3compliance.co.uk 

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

Office hours:

Every morning my full attention is on consultancy, testing, and troubleshooting 
activities for our customers’ projects. I’m contactable between 1300h to 1730h 
from Monday to Friday.

For inquiries, bookings, and testing updates please send us an email on  
 he...@unit3compliance.co.uk or call 01274 
911747. Our lead times for testing and consultancy are typically 4-5 weeks.

 

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Re: [PSES] dielectric strength question

[Ralph McDiarmid]

My understanding that “clearance” is distance through air (the insulating 
medium for clearance), not through solid or liquid insulation.  Clearance 
distance is a function of peak voltage and air pressure.  The testing of solid 
insulation is generally done using an impulse withstand voltage test.  
Clearance is tested using steady-state d.c. or the rms equivalent of an a.c. 
test voltage.

 

The tables for clearance and creepage along with the requirements for solid 
insulation appear to have served the industry well over the past few decades 
and there seems no compelling reason to scrutinize their origin, unless it can 
be shown that those requirements are generally inadequate or draconian.  I 
suspect there is a decent safety margin built-in to those numbers, maybe a 2:1 
factor.

 

Ralph

 

From: Richard Nute  
Sent: Tuesday, June 25, 2024 4:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] dielectric strength question

 

 

Hi John:

 

My concern is an engineering-based prediction of clearances (air insulation) as 
a function of voltage.  What is the basis for the clearance tables in the 
standards?  I have never seen anything that allows me to independently verify 
the clearance dimensions as a function of voltage.  My assumption was that the 
volts per unit distance through the insulating medium was an insulator 
constant.  Not true.  The volts per unit distance is a variable and depends on 
the distance.  So, how do I generate a table of distance for each voltage?  As 
near as I know, the tables are empirical.  

 

Your hypothesis is that the V/d curves are due to non-uniformity of the 
insulator is sort-of verified by the papers listed by Adam Dixon.  However, the 
incident you describe seems to me to be due to partial discharge.  Any V/d 
non-uniformity area of the insulating medium is a candidate for partial 
discharge.  Air, because its V/d is very much less than a solid insulator V/d, 
is likely to have sufficient voltage across the void and can lead to a partial 
breakdown of the solid insulator.  In the 1950s, I doubt that we knew much of 
the theory of partial discharge.

 

Best regards,

Rich

 

 

From: John Woodgate mailto:j...@woodjohn.uk> > 
Sent: Tuesday, June 25, 2024 1:26 PM
To: ri...@ieee.org  ; EMC-PSTC@LISTSERV.IEEE.ORG 
 
Subject: Re: [PSES] dielectric strength question

 

I feel that those curves support the hypothesis that the variation is due to 
non-uniformity in the material. I first suggested voids (because I recall a 
spectacular failure of a line output transformer design  in the late 1950s 
whose HV winding was encapsulated in polythene. Air in the voids ionized and 
the ions gobbled up the polythene. Attempt to eliminate the voids in viscous 
molten polythene under vacuum were partly successful, but did not survive the 
moulding process. Voids are only one possibility; simple variations in density 
may be sufficient to concentrate the electric field just where it will do the 
most damage.

Can some tests be done on a solid material that has been certified to be highly 
uniform? What happens with liquids, which should be orders of magnitude more 
uniform than the average solid?

On 2024-06-25 20:35, Richard Nute wrote:

 

Thanks to Adam for all the references.  They address very thin solid 
insulations.  But they confirm that dielectric strength is not a constant for 
very small distances, and they do not have an answer as to why.  

 

My concern is verifying clearances in safety standards.  I’ve attached curves 
of three standards clearance requirements (logarithmic scale for volts per 
millimeter).  The solid curves represent the clearances in standards and are 
close to power curves (dotted lines).  The equations are for a best-fit power 
curve.

 

The solid green curve is from an old standard and depicts actual withstand 
measurements.  

 

I suspect the electric strength curves are related to the reason for Paschen’s 
finding that gases do not break down at low voltages.  

 

My objective is to predict clearance dimensions without tables.

 

Best regards,

Rich

 

 


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Re: [PSES] HiPot Testing of 3-Phase PSU Question

[Ralph McDiarmid]

Some PSUs may have a screw or a jumper to remove for hipot testing.  Or you can 
hipot test your machine without the PSU connected, assuming the PSU has a 3rd 
party certification for electrical safety.

 

Ralph

 

From: Brian Kunde  
Sent: Monday, June 24, 2024 5:20 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] HiPot Testing of 3-Phase PSU Question

 

I understand that commercial products are %100 HiPot tested at the factory.  
Does this rule hold true for 3-phase industrial machinery?

 

Here is why I am asking.  I just pre-tested a German build 400-480Vac to 24Vdc 
power supply (DIN Rail Mount). It passed all the tests, except it failed the 
Phase-to-PE HiPot test at around 1000V. I tried both AC and DC voltage and 
tried connecting it from a single phase to PE and tried all phases connected 
together to PE.  I tested a second power supply of the same model and it did 
the same exact thing. So I am thinking that it is supposed to perform this way.

 

My concern is that in our factory, they will not be able to HiPot the final 
product when the power supply is installed.  

 

I assume the power supply has some kind of built in surge suppression. So how 
am I to use this PSU in my final product?

 

Thoughts and comments would be appreciated.

 

Best regards to all.

 

The Other Brian

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Re: [PSES] seeking a consultant

[Ralph McDiarmid]

My client needs a consultant for automotive functional safety.   

 

For those interested, I can setup call to discuss the details of the 
requirement.

 

Thank you,

 

Ralph

 


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Re: [PSES] SCCR Rating Question

[Ralph McDiarmid]

We have an answer from UL508A for industrial panels but the question was, “ 
SCCR ratings on industrial machinery”

 

Perhaps it is the question that is the difficulty here.

 

Ralph

 

From: Bill Lawrence  
Sent: Thursday, May 16, 2024 2:50 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] SCCR Rating Question

 

Assume UL 508A

 

Marking is:

 



-Original Message-
From: MIKE SHERMAN mailto:msherma...@comcast.net> >
Sent: May 15, 2024 10:38 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >
Subject: Re: [PSES] SCCR Rating Question

 

Brian —

 

I am equally mystified by qualifying an SCCR with a voltage. Perhaps you could 
network into a friendly UL 408a panel shop and see what they say.  

Mike Sherman 

Sherman PSC LLC

On 05/15/2024 9:05 AM -05 Brian Kunde mailto:bkundew...@gmail.com> > wrote:

 

 

I appreciate the replies, but I am not getting the information I am seeking.  

 

Some machines have just the SCCR Rating, such as 

 

SCCR: 10kA

 

but a few machines we have looked at include a reference to the "Max Voltage", 
such as

 

SCCR: 10kA RMS Symmetrical, 480V Maximum

 

What is the source, code, standard, directive, etc. that calls out the Max 
Voltage as a requirement in the SCCR rating that is printed on the Nameplate 
label?  We cannot find such a source.  

 

In our case, we have a machine that can operate at 230V, 380V, or 480V 
depending on how the motor is wired. So on a machine rated 230V it has a SCCR 
rating that includes the Max Voltage of 480V.  We are getting push-back from 
the field saying that having the voltage on the SCCR rating is confusing. To 
resolve this, we want to remove the reference to the Max Voltage, but before we 
do that, we want to find out if it is mandated in the code or some standard.  

 

I can see where the max voltage might be required on some components. Maybe it 
is an old requirement that is no longer required.  I am just guessing.  

 

Thanks again for your help.

The Other Brian

 

 

On Tue, May 14, 2024 at 3:54 PM Scott Aldous 
<0220f70c299a-dmarc-requ...@listserv.ieee.org 
<mailto:0220f70c299a-dmarc-requ...@listserv.ieee.org> > wrote:

Starting on page 7, the white paper that Rich linked to also references UL 
508A, supplement SB, which is a method of determining SCCR for industrial 
control panels without test. The method at a high level involves carrying over 
the SCCR rating of the "weakest link in the chain" from a protective component 
standpoint to the overall panel. I wonder if that method may have been used for 
the machinery in question, with a component level voltage rating (improperly, 
in my opinion) shifted over to the end device. Note that UL 508A includes "at a 
nominal voltage" in its definition of SCCR.

 

On Tue, May 14, 2024 at 12:33 PM Richard Nute mailto:ri...@ieee.org> > wrote:

 

Hi Brian:

 

See the very last line of:

 

https://www.mouser.com/pdfDocs/littelfuse_industrial_whitepaper_increase_sccr.pdf

 

Best regards,

Rich

 

 

 

 

From: Ralph McDiarmid mailto:rmm.priv...@gmail.com> > 
Sent: Tuesday, May 14, 2024 11:41 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] SCCR Rating Question

 

Could this number to used to select a suitable circuit breaker and so the 
interrupting voltage is an important parameter?

 

The nameplate rating on the machine should be the information an electrician 
needs during installation and selection of wire size and type.

 

Ralph

 

From: Brian Kunde mailto:bkundew...@gmail.com> > 
Sent: Tuesday, May 14, 2024 11:29 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] SCCR Rating Question

 

Greetings to all.  

 

I am new to SCCR ratings on industrial machinery.  The ratings I have seen 
sometimes has a "Maximum Voltage" included, such as;

 

SCCR: 22kA, 600V Maximum

 

Where does the voltage value come from?  In one case, the machine had a line 
voltage rating of "120/208 Vac", but the SCCR rating had a voltage rating of 
"Max 600V".

 

Can this be confusing? Might something think the machine can operate at 600Vac?

 

Thanks for any replies.

The Other Brian

 

 


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Re: [PSES] SCCR Rating Question

[Ralph McDiarmid]

I suggest that John has “nailed it”, as he often does.

 

Ralph

 

From: John Woodgate  
Sent: Wednesday, May 15, 2024 7:26 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] SCCR Rating Question

 

I cant help you with a reference to a standard, but there is a language problem 
and I think I can help with that, in the context of 'confusion'. The 'SSCR 
voltage' on the nameplate  actually means  'Minimum permitted value of the 
Maximum voltage of the SSCR'. Obviously those words are too long to put on the 
nameplate. In your case, obviously, the Max voltage of the SSCR must be at 
least 480 V if the motor is wired for 480 V operation, but could be lower if 
it's wired for a lower voltage. To document this, you  would need a BIG 
nameplate. Some standards allow a sign, usually a '!', to mean 'Refer to 
manual' or words to that effect, where you can put a full explanation.

On 2024-05-15 15:05, Brian Kunde wrote:

I appreciate the replies, but I am not getting the information I am seeking.  

 

Some machines have just the SCCR Rating, such as 

 

SCCR: 10kA

 

but a few machines we have looked at include a reference to the "Max Voltage", 
such as

 

SCCR: 10kA RMS Symmetrical, 480V Maximum

 

What is the source, code, standard, directive, etc. that calls out the Max 
Voltage as a requirement in the SCCR rating that is printed on the Nameplate 
label?  We cannot find such a source.  

 

In our case, we have a machine that can operate at 230V, 380V, or 480V 
depending on how the motor is wired. So on a machine rated 230V it has a SCCR 
rating that includes the Max Voltage of 480V.  We are getting push-back from 
the field saying that having the voltage on the SCCR rating is confusing. To 
resolve this, we want to remove the reference to the Max Voltage, but before we 
do that, we want to find out if it is mandated in the code or some standard.  

 

I can see where the max voltage might be required on some components. Maybe it 
is an old requirement that is no longer required.  I am just guessing.  

 

Thanks again for your help.

The Other Brian

 

 

On Tue, May 14, 2024 at 3:54 PM Scott Aldous 
<0220f70c299a-dmarc-requ...@listserv.ieee.org 
<mailto:0220f70c299a-dmarc-requ...@listserv.ieee.org> > wrote:

Starting on page 7, the white paper that Rich linked to also references UL 
508A, supplement SB, which is a method of determining SCCR for industrial 
control panels without test. The method at a high level involves carrying over 
the SCCR rating of the "weakest link in the chain" from a protective component 
standpoint to the overall panel. I wonder if that method may have been used for 
the machinery in question, with a component level voltage rating (improperly, 
in my opinion) shifted over to the end device. Note that UL 508A includes "at a 
nominal voltage" in its definition of SCCR.

 

On Tue, May 14, 2024 at 12:33 PM Richard Nute mailto:ri...@ieee.org> > wrote:

 

Hi Brian:

 

See the very last line of:

 

https://www.mouser.com/pdfDocs/littelfuse_industrial_whitepaper_increase_sccr.pdf

 

Best regards,

Rich

 

 

 

 

From: Ralph McDiarmid mailto:rmm.priv...@gmail.com> > 
Sent: Tuesday, May 14, 2024 11:41 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] SCCR Rating Question

 

Could this number to used to select a suitable circuit breaker and so the 
interrupting voltage is an important parameter?

 

The nameplate rating on the machine should be the information an electrician 
needs during installation and selection of wire size and type.

 

Ralph

 

From: Brian Kunde mailto:bkundew...@gmail.com> > 
Sent: Tuesday, May 14, 2024 11:29 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] SCCR Rating Question

 

Greetings to all.  

 

I am new to SCCR ratings on industrial machinery.  The ratings I have seen 
sometimes has a "Maximum Voltage" included, such as;

 

SCCR: 22kA, 600V Maximum

 

Where does the voltage value come from?  In one case, the machine had a line 
voltage rating of "120/208 Vac", but the SCCR rating had a voltage rating of 
"Max 600V".

 

Can this be confusing? Might something think the machine can operate at 600Vac?

 

Thanks for any replies.

The Other Brian

 

 


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Re: [PSES] SCCR Rating Question

[Ralph McDiarmid]

Could this number to used to select a suitable circuit breaker and so the 
interrupting voltage is an important parameter?

 

The nameplate rating on the machine should be the information an electrician 
needs during installation and selection of wire size and type.

 

Ralph

 

From: Brian Kunde  
Sent: Tuesday, May 14, 2024 11:29 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] SCCR Rating Question

 

Greetings to all.  

 

I am new to SCCR ratings on industrial machinery.  The ratings I have seen 
sometimes has a "Maximum Voltage" included, such as;

 

SCCR: 22kA, 600V Maximum

 

Where does the voltage value come from?  In one case, the machine had a line 
voltage rating of "120/208 Vac", but the SCCR rating had a voltage rating of 
"Max 600V".

 

Can this be confusing? Might something think the machine can operate at 600Vac?

 

Thanks for any replies.

The Other Brian

 

 

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Re: [PSES] IEC 62368-1: To understand chapter 5.4.11

[Ralph McDiarmid]

The IEC store has IEC TR 62368-2:2019 RLV for 553 Swiss Francs.   Ouch.

 

From: John Woodgate  
Sent: Wednesday, May 8, 2024 1:37 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] IEC 62368-1: To understand chapter 5.4.11

 

You can get 62368-2 from: https://www.evs.ee/en/iec-tr-62368-2-2019, but it is 
rather costly.

On 2024-05-08 21:00, Piotr Galka wrote:

After reading your post my decision was to buy 62368-2 but I've just checked 
that in PKN (Polish Standards Committee) I can buy 62368-1 what I have done 
long ago but they don't have 62368-2 :( .

-- 
OOO - Own Opinions Only
Best wishes
John Woodgate, Rayleigh, Essex UK
Keep trying

 


 

 

Virus-free. 

 www.avg.com

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Re: [PSES] Couple of loosely related safety questions

[Ralph McDiarmid]

Brian, for a rigorous determination of creepage and of clearance you need to
also determine and assign:

 

1.  Over-voltage Category ( affects Clearance )
2.  Pollution Degree  ( micro-environment affecting Creepage )
3.  Basic (simple separation) or Reinforced (protective separation)
boundaries (if the end-product standard distinguishes)

 

If you can determine that slots are needed to increase a creepage path
because of physical constraints, then the minimum allowable width of that
slot needs to be determined.  

 

The application of std UL840 is permitted as an alternative for the
determination of spacings, with some strings attached to the end-product
standard ( e.g. UL1741 referencing UL840)

 

It’s a long and winding, foggy road to follow when determining minimum
spacings for an electronic assembly.  Isolation planning, assignment of
working voltages (RMS and peak) across isolation boundaries is usually a
good first step.  

 

Your MOSFET lead spacing doesn’t need to follow PCB rules, but the PCB does.
You may need to measure distance between PCB pads for the device and if then
decide if those pads might need slots between them.

 

Ralph

 

From: Brian Gregory  
Sent: Friday, April 26, 2024 4:12 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Couple of loosely related safety questions

 

 

1.  Clearances for US Safety:  

 

I'd cite the relevant standards, but they are so alike (identical Clearance
tables), and so alike to UL 508, I'll defer.  Here's the question:

 

When citing clearance spacing from "uninsulated live components"  does one
measure from the edge of a PCB to the enclosure well, or only from the live
components, like a pad, or the bottom pin of a thru-hole cap?

1a.  what sort of passivation or RTV could make those live components not
"uninsulated"?

 

2.  Slots to increase creepage for high-voltage components

 

A FET that's rated for say 600V does not have to follow PCB-creepage rules
for 600V, is clearly stated places like UL 1741, §26.1.1 exception #8.  For
other components, like say 1000V caps in 0805 packages or FET driver chips
the requirements aren't as clear.  Is a slot needed to maintain creepage or
not if the component is properly rated?  It does appear from a TI support
page for dual-bridge converters, that slots are recommended in order to
prevent contamination that may compromise the components isolation
performance.

 

My gut says:  no, slots are not needed between component terminals on a PCB,
but could be recommended for sensitive parts, like FET drivers.

 

Thoughts? 

 

Colorado Brian 

 

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Re: [PSES] OJEC list of harmonised standards

[Ralph McDiarmid]

Thank you, Bart.  I'll try that link for EMC and LVD harmonized standards
listing.

 

Kind regards,

 

Ralph

 

From: bart.de.gee...@telenet.be  
Sent: Wednesday, April 17, 2024 10:06 AM
To: rmm.priv...@gmail.com; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] OJEC list of harmonised standards

 

Hi Ralph,

 

Is this what you are looking for?

 

https://single-market-economy.ec.europa.eu/single-market/european-standards/
harmonised-standards_en

 

Greetings,

Bart

 

From: Ralph McDiarmid mailto:rmm.priv...@gmail.com>
> 
Sent: woensdag 17 april 2024 19:04
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] OJEC list of harmonised standards

 

Can someone provide a link to this list.  I have searched eur-lex.europa.eu
website without success.  

 

Ralph

 

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Re: [PSES] OJEC list of harmonised standards

[Ralph McDiarmid]

Can someone provide a link to this list.  I have searched eur-lex.europa.eu
website without success.  

 

Ralph

 


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Re: [PSES] Radiated Emissions - How many points to QP?

[Ralph McDiarmid]

I was thinking conducted emissions in the context of average detectors.

 

From: Brent DeWitt  
Sent: Friday, April 5, 2024 3:48 PM
To: rmm.priv...@gmail.com; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Radiated Emissions - How many points to QP?

 

Could you clarify when you would choose to use an average detector for radiated 
emissions between 30 and 1000 MHz?

On 4/5/2024 6:39 PM, Ralph McDiarmid wrote:

I’m having trouble with “Of those disturbances above (L-20dB), where L is the 
limit level in logarithmic units, the disturbance levels and the frequencies of 
at least the six highest disturbances shall be recorded.”

 

Does this CISPR measurement methods standard expect you to record the six 
highest signals which are less than or equal to -20dB wrt the average limit 
when using an average detector and the QP limit when using a QP detector? 
Perhaps that is made clear in the product-specific standard (like EN55022 or 
CISPR 11, etc)

 

Comments?

 

 

Ralph

 

 

From: Stultz, Mark  <mailto:0f79f2e10e47-dmarc-requ...@listserv.ieee.org> 
<0f79f2e10e47-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, April 5, 2024 12:33 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] Radiated Emissions - How many points to QP?

 

Hello PSES brain trust,

When doing radiated emissions measurements, how many frequencies should be 
quasi-peaked?  

CISPR 16-2-3 clause 6.4.9 states: 

“Of those disturbances above (L-20dB), where L is the limit level in 
logarithmic units, the disturbance levels and the frequencies of at least the 
six highest disturbances shall be recorded.”

 

We have always done QP measurements on all peak measurements above the limit, 
even if that is more than six points.

I have a lab arguing that they only need to measure the top six, regardless of 
how many peak measurements are above the limit.

Any thoughts are appreciated.

 

Thanks,

Mark


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Re: [PSES] I would like to hear your thoughts please

[Ralph McDiarmid]

That has been my experience with CB Scheme, E-mark, and product safety in the 
USA using an NRTL.  Namely, pick worst-case with justifications, talk with your 
certifier, and reach an understanding.  If they won't budge and insist on full 
testing of every variant, move to another certifier who is willing to listen to 
reason.

If the "code" is different and your firmware is a functional safety component, 
then you may not have much choice but to repeat at least some of the tests 
called out in the test plan to verify nothing was "broken" when tweaking the 
firmware to accommodate each hardware variant.

Ralph

-Original Message-
From: Lfresearch <00734758d943-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, April 5, 2024 3:47 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] I would like to hear your thoughts please

Hi folks,

I would like to advise a client at where to draw the line on what needs 
testing. I would like to solicit opinions besides my own. Otherwise it’s the 
fox urging the chicken coop…

So a manufacturer that makes a product of which there will be several variants. 
All use the same board, but have different sections of circuits populated. This 
may require slightly different code to run on the same uP in each case.

So.. The burning question is can we perform and analysis that postulates a 
worse case hardware/software combination and test just one configuration? Or, 
do we have to do every combination?

Or, are there some guidelines about where we draw the line of what to test and 
what can be claimed as similarity?

Off list responses are welcome too.

Thanks,

Derek Walton
LFResearch/SSCLabs.

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Re: [PSES] Radiated Emissions - How many points to QP?

[Ralph McDiarmid]

I'm having trouble with "Of those disturbances above (L-20dB), where L is
the limit level in logarithmic units, the disturbance levels and the
frequencies of at least the six highest disturbances shall be recorded."

 

Does this CISPR measurement methods standard expect you to record the six
highest signals which are less than or equal to -20dB wrt the average limit
when using an average detector and the QP limit when using a QP detector?
Perhaps that is made clear in the product-specific standard (like EN55022 or
CISPR 11, etc)

 

Comments?

 

 

Ralph

 

 

From: Stultz, Mark <0f79f2e10e47-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, April 5, 2024 12:33 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Radiated Emissions - How many points to QP?

 

Hello PSES brain trust,

When doing radiated emissions measurements, how many frequencies should be
quasi-peaked?  

CISPR 16-2-3 clause 6.4.9 states: 

"Of those disturbances above (L-20dB), where L is the limit level in
logarithmic units, the disturbance levels and the frequencies of at least
the six highest disturbances shall be recorded."

 

We have always done QP measurements on all peak measurements above the
limit, even if that is more than six points.

I have a lab arguing that they only need to measure the top six, regardless
of how many peak measurements are above the limit.

Any thoughts are appreciated.

 

Thanks,

Mark

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Re: [PSES] GFCI Receptacles

[Ralph McDiarmid]

NFPA can be viewed free online, however, CSA C22.1, C22.3, and C22.3 appear
to be by purchase only.

 

 

Ralph

 

From: Don Gies <2f2a08db2fba-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, April 5, 2024 11:20 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] GFCI Receptacles

 

Hi Steve, 

 

Hope all is well with you.  

 

See the National Electrical Code, NFPA 70, Article 210.8 for the list of
locations that require GFCI in the US.

 

In Canada, see Canadian Electrical Code, Part I, CSA C22.1, Rule 26-704 and
26-710, as well as other locations for GFCI requirements.

 

Best regards,

 

DON GIES

Field Service Engineer

 



 

p   +1 346 313 6216

e   donald.g...@non.se.com  

w  gutor.com

 

17 Capitol Reef Road

Howell, NJ 07731

United States

 



 

 

 

 

General

From: sgbrody mailto:sgbr...@comcast.net> > 
Sent: Monday, March 25, 2024 21:18
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] GFCI Receptacles

 

[External email: Use caution with links and attachments]

  _  

 

Esteemed experts:

 

It has always been what I thought was the requirement for GFCI receptacles
was only when the product or system was intended for a wet or damp location.

 

A system a client is having an NRTL fo a Field Evaluation on had receptacles
and they are being told they need to be GFCI.

 

NFPA-79 15.1.1 requires this only for receptacles to be used for, e.g.,
handheld power tools, test equipment, and other accessories.

 

The questions are:

- What is the definition of accessories as used in NFPA-79,

 - And is it written in any other standard where and when GFCI outlets are
required?

 

Thank you.

 

 

 

 

Sent from my T-Mobile 5G Device

 

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Re: [PSES] Fire codes related to batteries

[Ralph McDiarmid]

And, NFPA provides free, online, read-only access to all their standards.
So does UL.

 

Ralph

 

From: Don Gies <2f2a08db2fba-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, April 5, 2024 11:02 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Fire codes related to batteries

 

Hi Gary,

 

NFPA 1, Section 52 is very comprehensive. 

 

Also, see IEEE Std 1679.1, " IEEE Guide for the Characterization and
Evaluation of Lithium-Based Batteries in Stationary Applications."

 

Best regards,

 

DON GIES

Field Service Engineer

 



 

p   +1 346 313 6216

e   donald.g...@non.se.com  

w  gutor.com

 

17 Capitol Reef Road

Howell, NJ 07731

United States

 



 

 

 

 

General

From: Gary Tornquist <05big...@gmail.com  > 
Sent: Monday, April 1, 2024 12:47
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] Fire codes related to batteries

 

[External email: Use caution with links and attachments]

  _  

 

Hello Experts,

My client is using large capacity lithium-ion battery backup units in his
facility

 

The BBU's themselves are safety approved and also have UL9540A testing done
at the rack level. 

 

We are looking for code consultation (NFPA and ICC/IFC) to gather
requirements around the following: 

 

1.  Storage of batteries before installation in the facility. 
2.  Ventilation and fire suppression requirements 
3.  Spacing requirements 
4.  Any other code requirements that apply at the facility for use of
these BBU's. 

 

If you are able to assist with the request and have a code expert that can
provide the consultation, please let me know. 

 

Cheers,
Gary Tornquist

 

 

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Re: [PSES] UL 62133-2 Battery Standard + V-1 plastic enclosure

[Ralph McDiarmid]

Many product safety standards require vertical flame rating for polymeric 
material forming part or all of the enclosure.  I’m surprized it doesn’t 
require V-0 or 5VA.  It’s seems to be about containing a fire inside the 
enclosure.

 

Ralph

 

From: emcl...@gmail.com  
Sent: Thursday, March 21, 2024 1:32 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] UL 62133-2 Battery Standard + V-1 plastic enclosure

 

Hello All,

 

This is the first time that I've had a large NRTL safety engineer inform me 
that the UL 62133-2 battery pack standard requires that the end-product 
application enclosure plastic must be rated V-1 or better.  I don't have that 
standard.  Can anybody here shed some light on this issue?

 

Thanks much, 

 

Carl

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Re: [PSES] 61010-1 hazardous live classification

[Ralph McDiarmid]

Then again, what is the effective value of the 42Vpeak pulsed d.c. ?  Does
it exceed the Vrms limit at your highest duty ratio?   You mentioned a 0.01%
minimum on-time, but what is the maximum?

 

 

From: James Pawson (U3C)  
Sent: Monday, February 26, 2024 5:38 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] 61010-1 hazardous live classification

 

Hello all,

 

I hope this safety question is a fairly simple one for you, it being Monday
after all.

 

1.  A piece of equipment with a power supply output for driving a lamp.
It has two modes, DC and pulsed.
2.  Both of the output voltage connections are on accessible terminals
(checked using finger probe)
3.  Classifying voltages as per EN 61010-1 clause 6.3.1 (limit values
for accessible parts, normal operating conditions)
4.  DC mode runs at 46Vdc maximum. This is less than 60Vdc so is not
Hazardous Live
5.  Pulse mode runs at 46Vdc pulsed (frequency up to 1kHz, duty cycle
can vary down to 0.01%) which is an AC waveform greater than 42.4V peak so
is Hazardous Live
6.  The output from the equipment is low impedance so is more than
capable of sourcing the required 0.7mA through the IEC 60990 body model.

 

Quick sketch attached to illustrate the concept. I even ran a SPICE
simulation to make sure I wasn't getting something wrong.

 

I would appreciate the sanity check!

 

All the best

James

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
Consultancy

 

www.unit3compliance.co.uk   |
ja...@unit3compliance.co.uk   

+44(0)1274 911747  |  +44(0)7811 139957

2 Wellington Business Park, New Lane, Bradford, BD4 8AL

Registered in England and Wales # 10574298

 

Office hours:

Every morning my full attention is on consultancy, testing, and
troubleshooting activities for our customers' projects. I'm
available/contactable between 1300h to 1730h Mon/Tue/Thurs/Fri.

For inquiries, bookings, and testing updates please send us an email on
 he...@unit3compliance.co.uk or call
01274 911747. Our lead times for testing and consultancy are typically 4-5
weeks.

 

 

 

 

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Re: [PSES] 61010-1 hazardous live classification

[Ralph McDiarmid]

Thanks Scott.  I will read that preview.

 

From: Scott Aldous  
Sent: Monday, February 26, 2024 3:21 PM
To: rmm.priv...@gmail.com
Cc: EMC-PSTC@listserv.ieee.org
Subject: Re: [PSES] 61010-1 hazardous live classification

 

Use of shock hazard limits in terms of voltage in product safety standards is 
already a simplification. See IEC 60479-1 and -2. You can find the free preview 
of IEC 60479-1 here 
<https://webstore.iec.ch/preview/info_iec60479-1%7Bed1.0%7Den.pdf> , with a 
good high level discussion in the scope.

 

On Mon, Feb 26, 2024 at 2:26 PM Ralph McDiarmid mailto:rmm.priv...@gmail.com> > wrote:

I suspect many of the standards committee have merely adopted the Vpeak limit 
from other standards without giving it much thought.  Note that 42.4Vpk is just 
root2 x 30Vrms.  That seems to be all there is to it and I doubt it’s mere 
coincidence.  (60Vdc/30Vrms/42.4Vpk found in several standards)

 

I went back to first principles, did the integration of a d.c pulsed waveform 
and then again for an a.c. waveform with same amplitude, same duty ratio.  I 
found a much higher effective value (RMS) with the a.c. waveform having sample 
amplitude and pulse duty ratio.  For example, Root2 higher for 50% duty cycle 
and Root10 higher for 10% duty cycle.

 

Now, the NRTL won’t be interested in any of that, but you need to weigh the 
intent of the standard versus any other risk analysis might do above and beyond 
the “letter of the law” before deciding on whether those terminals are in fact 
shock hazardous.  It’s your product, your call, your corporate reputation, so 
whatever the decision, it needs to be justified with due diligence.

 

I would say your power supply output as described satisfies the criteria of 
“limit values for accessible parts” as defined in IEC61010 3rd edition.  (33 
Vrms, 33xroot2 Vpeak, and 70 Vdc )   A project holder at an NRTL might disagree.

 

Ralph

 

From: Richard Nute mailto:ri...@ieee.org> > 
Sent: Monday, February 26, 2024 12:08 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] 61010-1 hazardous live classification

 

 

Hi James:

 

In the pulse mode, 46 volts peak exceeds the 42.4 volts peak limit.  In 
accordance with the 61010 standard, the voltage cannot be accessible in the 
pulse mode.

 

However, the pulse mode is dc (the current does not reverse).  The RMS of such 
a pulse is 46 times the square root of the duty cycle.  The shorter the duty 
cycle, the less human sensation of the pulse.  Chances are that the pulse is 
not detectable by a human finger any more than 60 volts DC.  But the standard 
does not allow such a determination.  

 

You are stuck.

 

Best regards,

Richard Nute

Bend, Oregon, USA

 

 

From: James Pawson (U3C) mailto:ja...@unit3compliance.co.uk> > 
Sent: Monday, February 26, 2024 5:38 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] 61010-1 hazardous live classification

 

Hello all,

 

I hope this safety question is a fairly simple one for you, it being Monday 
after all…

 

1.  A piece of equipment with a power supply output for driving a lamp. It 
has two modes, DC and pulsed.
2.  Both of the output voltage connections are on accessible terminals 
(checked using finger probe)
3.  Classifying voltages as per EN 61010-1 clause 6.3.1 (limit values for 
accessible parts, normal operating conditions)
4.  DC mode runs at 46Vdc maximum. This is less than 60Vdc so is not 
Hazardous Live
5.  Pulse mode runs at 46Vdc pulsed (frequency up to 1kHz, duty cycle can 
vary down to 0.01%) which is an AC waveform greater than 42.4V peak so is 
Hazardous Live
6.  The output from the equipment is low impedance so is more than capable 
of sourcing the required 0.7mA through the IEC 60990 body model.

 

Quick sketch attached to illustrate the concept. I even ran a SPICE simulation 
to make sure I wasn’t getting something wrong.

 

I would appreciate the sanity check!

 

All the best

James

 


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Re: [PSES] 61010-1 hazardous live classification

[Ralph McDiarmid]

I suspect many of the standards committee have merely adopted the Vpeak
limit from other standards without giving it much thought.  Note that
42.4Vpk is just root2 x 30Vrms.  That seems to be all there is to it and I
doubt it's mere coincidence.  (60Vdc/30Vrms/42.4Vpk found in several
standards)

 

I went back to first principles, did the integration of a d.c pulsed
waveform and then again for an a.c. waveform with same amplitude, same duty
ratio.  I found a much higher effective value (RMS) with the a.c. waveform
having sample amplitude and pulse duty ratio.  For example, Root2 higher for
50% duty cycle and Root10 higher for 10% duty cycle.

 

Now, the NRTL won't be interested in any of that, but you need to weigh the
intent of the standard versus any other risk analysis might do above and
beyond the "letter of the law" before deciding on whether those terminals
are in fact shock hazardous.  It's your product, your call, your corporate
reputation, so whatever the decision, it needs to be justified with due
diligence.

 

I would say your power supply output as described satisfies the criteria of
"limit values for accessible parts" as defined in IEC61010 3rd edition.  (33
Vrms, 33xroot2 Vpeak, and 70 Vdc )   A project holder at an NRTL might
disagree.

 

Ralph

 

From: Richard Nute  
Sent: Monday, February 26, 2024 12:08 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] 61010-1 hazardous live classification

 

 

Hi James:

 

In the pulse mode, 46 volts peak exceeds the 42.4 volts peak limit.  In
accordance with the 61010 standard, the voltage cannot be accessible in the
pulse mode.

 

However, the pulse mode is dc (the current does not reverse).  The RMS of
such a pulse is 46 times the square root of the duty cycle.  The shorter the
duty cycle, the less human sensation of the pulse.  Chances are that the
pulse is not detectable by a human finger any more than 60 volts DC.  But
the standard does not allow such a determination.  

 

You are stuck.

 

Best regards,

Richard Nute

Bend, Oregon, USA

 

 

From: James Pawson (U3C) mailto:ja...@unit3compliance.co.uk> > 
Sent: Monday, February 26, 2024 5:38 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] 61010-1 hazardous live classification

 

Hello all,

 

I hope this safety question is a fairly simple one for you, it being Monday
after all.

 

1.  A piece of equipment with a power supply output for driving a lamp.
It has two modes, DC and pulsed.
2.  Both of the output voltage connections are on accessible terminals
(checked using finger probe)
3.  Classifying voltages as per EN 61010-1 clause 6.3.1 (limit values
for accessible parts, normal operating conditions)
4.  DC mode runs at 46Vdc maximum. This is less than 60Vdc so is not
Hazardous Live
5.  Pulse mode runs at 46Vdc pulsed (frequency up to 1kHz, duty cycle
can vary down to 0.01%) which is an AC waveform greater than 42.4V peak so
is Hazardous Live
6.  The output from the equipment is low impedance so is more than
capable of sourcing the required 0.7mA through the IEC 60990 body model.

 

Quick sketch attached to illustrate the concept. I even ran a SPICE
simulation to make sure I wasn't getting something wrong.

 

I would appreciate the sanity check!

 

All the best

James

 

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Re: [PSES] 61010-1 hazardous live classification

[Ralph McDiarmid]

An immaculate analysis and air-tight conclusion, as I see it.

 

 

From: James Pawson (U3C)  
Sent: Monday, February 26, 2024 5:38 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] 61010-1 hazardous live classification

 

Hello all,

 

I hope this safety question is a fairly simple one for you, it being Monday
after all.

 

1.  A piece of equipment with a power supply output for driving a lamp.
It has two modes, DC and pulsed.
2.  Both of the output voltage connections are on accessible terminals
(checked using finger probe)
3.  Classifying voltages as per EN 61010-1 clause 6.3.1 (limit values
for accessible parts, normal operating conditions)
4.  DC mode runs at 46Vdc maximum. This is less than 60Vdc so is not
Hazardous Live
5.  Pulse mode runs at 46Vdc pulsed (frequency up to 1kHz, duty cycle
can vary down to 0.01%) which is an AC waveform greater than 42.4V peak so
is Hazardous Live
6.  The output from the equipment is low impedance so is more than
capable of sourcing the required 0.7mA through the IEC 60990 body model.

 

Quick sketch attached to illustrate the concept. I even ran a SPICE
simulation to make sure I wasn't getting something wrong.

 

I would appreciate the sanity check!

 

All the best

James

 

James Pawson

Managing Director & EMC Problem Solver

 

Unit 3 Compliance Ltd

EMC : Environmental & Vibration : Electrical Safety : CE & UKCA :
Consultancy

 

www.unit3compliance.co.uk   |
ja...@unit3compliance.co.uk   

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Registered in England and Wales # 10574298

 

Office hours:

Every morning my full attention is on consultancy, testing, and
troubleshooting activities for our customers' projects. I'm
available/contactable between 1300h to 1730h Mon/Tue/Thurs/Fri.

For inquiries, bookings, and testing updates please send us an email on
 he...@unit3compliance.co.uk or call
01274 911747. Our lead times for testing and consultancy are typically 4-5
weeks.

 

 

 

 

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Re: [PSES] IEC 62368-3

[Ralph McDiarmid]

In the 3rd edition of IEC 62368-1, it reads, 

 

“Additional requirements for equipment having the capability to supply DC power 
over
commonly used communication cables, such as USB or Ethernet (PoE), are given in
IEC 62368-3.” 

 

Ralph

 

From: peterh...@aol.com <06cee064502d-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, January 19, 2024 12:52 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] IEC 62368-3

 

Hello group,

 

Would I be correct to say that even though the above standard is reference in 
IEC 62368-1 3rd Ed but it is considered optional and not mandatory? 

Thank you
Peter

 

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Re: [PSES] Products requiring dielectric voltage withstand test on RJ45 and XLR sockets

[Ralph McDiarmid]

If you test that connector with the blunt test probe (aka finger probe)
using the procedure described in the standard and it does not touch the
connector pins (and you have minimum clearance) then your certifier should
reconsider the dielectric test level.  Many standards still use basic and
reinforced insulation concepts along with working voltage to determine
dielectric type test and routine test levels.

 

From: Chuck August-McDowell  
Sent: Tuesday, January 16, 2024 4:33 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Products requiring dielectric voltage withstand test on RJ45
and XLR sockets

 

I'm working with a new lab and new product using IEC 62368-1 3rd Ed.

they are asking the company to perform production line test dielectric
voltage withstand test of 3600 Vp or DC 1 to 4 seconds on Ethernet port
connector RJ45 and Pro Audio XLR connector sockets?

"Between primary to other accessible conductive part- L/N of plus pins to
accessible unearthed socket terminals"

 

Can I use the IEC 62368-1 3rd Ed. blunt probe of Figure V.3 to show that the
pins are not accessible and need not be tested?

 

Anyone else must production line Hipot Ethernet port connector RJ45 or Pro
Audio XLR connector sockets?

 

Thank you for the help.

 

 

Chuck

 

 

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Re: [PSES] Is certification 'voided' by improper operational conditions?

[Ralph McDiarmid]

Hi Lauren,

 

MCCB (molded case circuit breakers) get hot when they are run close to their
handle rating, even open bench.  If installed in a panel (dead air space) at
40C ambient temperature, I would expect they would easily exceed 50C on
their molded case long before say 3 hours have expired (continuous current
as defined in NFPA 70).  Their terminals are rated for 60C wire,  so those
terminals (the internal parts connected to them) can get at least that hot.
If simply heat-soaked at zero current at 50C, I'd say you have no worries.

 

It is always wise to write to the manufacturer of the circuit breaker and
ask them if they can check the "conditions of acceptability" which normally
accompanies any UL recognition.  Include ALL your test conditions in your
correspondence.

 

 

From: Lauren Crane <1afd08519f18-dmarc-requ...@listserv.ieee.org> 
Sent: Friday, January 5, 2024 4:48 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Is certification 'voided' by improper operational
conditions?

 

Hello Experts, 

 

If I have UL certified component and operate it for a period of time outside
its specified conditions of operation, and then return the conditions to
specified levels, is it appropriate to still think of the component as
certified, or is the certification somehow voided by this accident? 

 

For example, a circuit breaker rated for 40degC max ambient run at 50degC
ambient for 8 hours and then ambient temp brought down to 30degC.  

 

Best Regards, 

-Lauren

 

Happy to receive recall-opinions and educated guesses but would love
'chapter and verse' citations if available.


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Re: [PSES] [EXTERNAL] [PSES] General Product Safety Directive (GPSD)

[Ralph McDiarmid]

I found that too, but isn’t the GPSD a “new approach” directive ?   I am sure 
it must be; it was certainly published after 1985.  By that criterion alone, it 
seems appropriate to apply the mark.   

 

From: John Mcbain  
Sent: Wednesday, November 1, 2023 1:49 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] [EXTERNAL] [PSES] General Product Safety Directive (GPSD)

 

Correct. Or more specifically - 

 

https://single-market-economy.ec.europa.eu/single-market/ce-marking_en#:~:text=It%20is%20compulsory%20only%20for,origin%20of%20a%20product%20either.




Best regards,

John McBain

 

 

On Wed, Nov 1, 2023 at 1:20 PM John Woodgate mailto:j...@woodjohn.uk> > wrote:

Somewhere in all the Byzantine rules, there is a ban on applying the CE mark if 
no Directive or Regulation that demands it applies to the product.

On 2023-11-01 19:58, Ralph McDiarmid wrote:

Furthermore, I have not found anything document which says that you cannot CE 
mark a product having a DofC listing the GPSR.  The proviso that you can issue 
a DofC against Directive 2001/95/EC but cannot CE mark the product is not 
stated anywhere in the official website of the EU (Europa.eu) or in the GPSD.  
Perhaps it’s just well hidden. 


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Re: [PSES] [EXTERNAL] [PSES] General Product Safety Directive (GPSD)

[Ralph McDiarmid]

What is meant by “safety information on the Declaration of Conformity”?  A DofC 
contains a list of applicable EU directives and standards.  I’ve never been 
asked to draft a DofC for signature with “safety information” in it.

 

Furthermore, I have not found anything document which says that you cannot CE 
mark a product having a DofC listing the GPSR.  The proviso that you can issue 
a DofC against Directive 2001/95/EC but cannot CE mark the product is not 
stated anywhere in the official website of the EU (Europa.eu) or in the GPSD.  
Perhaps it’s just well hidden. 

 

If you don’t CE mark, you’ll have trouble with a few countries in the EU.  
Customs people seem to look for that mark, even though it is not a formal 
condition of import.  

 

 

Ralph

 

From: John Woodgate  
Sent: Wednesday, November 1, 2023 12:01 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] [EXTERNAL] [PSES] General Product Safety Directive (GPSD)

 

Precisely. It's utter folly not to carry out, and document, appropriate safety 
tests.

On 2023-11-01 18:35, Ted Eckert wrote:

Hello Amund,

 

The GPSR is not a CE-marking Directive, and products that fall under the GPSR 
can be placed on the market without safety information on the Declaration of 
Conformity if they do not fall under any other Directive that requires a 
declaration for safety. However, that is only related to what is on the 
Declaration of Conformity, affecting the ability to properly import a product 
into the EU.

 

However, regulations on the import of products are not the only regulations 
affecting product safety requirements. Product liability law exists in the 27 
EU member states. If you have a professional product meeting the requirements 
you propose, and there is some allegation of a safety issue, the customer can 
seek remedies from the importer, distributor, and/or manufacturer. Your ability 
to defend your company in court will be significantly diminished if you have no 
documentation showing that a safety analysis has been done. 

 

In general, all of the economic actors involved in selling products carry the 
responsibility of making sure the products they sell meet legal requirements. 
It will be up to your legal department to determine the risk of placing a 
product on the market without a safety evaluation. The need for producing 
safety documentation might not be limited only to the RED, LVD, or GPSR.

 

Best regard,

Ted Eckert

 

The opinions expressed are my own and do not necessarily reflect those of my 
employer.

 

 

From: Amund Westin   
 
Sent: Wednesday, November 1, 2023 12:41 AM
To: Ted Eckert   ; 
EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: SV: [EXTERNAL] [PSES] General Product Safety Directive (GPSD)

 

Thanks Ted,

 

As I read your comments and take they into an example - … consider a 
professional electronic product, which can’t be bought or even used by 
consumers, will not under any circumstances be covered by GPSD/GPSR. Right?

And if product is low powered (not within LVD), then maybe only EMC apply. Then 
the product could be put on the market without any safety related tests …. Is 
that correct?

 

 

BR
Amund

 

 

Fra: Ted Eckert 
Sendt: 31. oktober 2023 16:10
Til: Amund Westin <  
am...@westin-emission.no>;   
EMC-PSTC@LISTSERV.IEEE.ORG
Emne: RE: [EXTERNAL] [PSES] General Product Safety Directive (GPSD)

 

Hello Amund,

 

The GPSR has these definitions. I recommend you use them as the basis to 
determine if you are providing “consumer products” as covered by the scope of 
the GPSR.

  

“‘product’ means any item, whether or not it is interconnected to other items, 
supplied or made available, whether for consideration or not, including in the 
context of providing a service, which is intended for consumers or is likely, 
under reasonably foreseeable conditions, to be used by consumers even if not 
intended for them”.

 

“’consumer’ means any natural person who acts for purposes which are outside 
that person’s trade, bushiness, craft or profession”.

 

There is no clear line drawn between consumer and professional equipment, and 
the GPSR is intended to cover professional equipment that is likely to be 
purchased for personal use by some consumers. Products that fall into this grey 
area may need to be reviewed on a case-by-case basis. I would recommend that if 
you determine a product is not within the scope, your technical file include a 
clear explanation of why it is out of scope.

 

Best regard,

Ted Eckert

 

The opinions expressed are my own and do not necessarily reflect those of my 
employer.

 

 

 

-Original Message-
From: Amund Westin mailto:am...@westin-emission.no> 
> 
Sent: Tuesday, October 31, 2023 7:54 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [EXTERNAL] [PSES] 

Re: [PSES] 2 simple questions on EMC

[Ralph McDiarmid]

The EMC standard with which I am familiar (CISPR11, EN55022) are well
written and provide examples of best practice setup and how to arrange
excess cable length.  I suggest going over the standard with the test
technician at the EMC lab to better understand the requirement.

 

If it were my product, I wouldn't lose a minute's sleep over a 1dB pass at a
narrow range of frequency in the test spectrum, however, I would want to
test at rated power.  You may find that peak rises with increasing EUT
power.

 



 

Ralph

 

 

From: Brian Gregory  
Sent: Tuesday, October 31, 2023 2:29 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] 2 simple questions on EMC

 

Hi,

 

1.  Our unit is passing by a whisker, under 1dB @ 30 Mhz in a 3m chamber
against SubpartB requirements.  Can we expect margin to improve in a 10m
chamber?

 

2.  It's lightly loaded in the chamber (10% of FL), we do expect the peak to
squash down a bit with full load;  they do when going from zero load to 10%.


 

3.  We were idly wondering about cable loop;  the output cable (bundled AWG
#6) is 6' runs about 12" in front of the unit towards the antenna and the
balance of it is currently coiled up in a loose bundle under the test setup.
The standards don't say anything about cable routing, just that it should be
on the ground plane.  I don't like it running 'in front' of the unit, but
the lab tech says that's pretty standard and not driven by the necessities
of the test setup.  Is that standard for a radiated setup?

 

Colorado Brian 

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Re: [PSES] safety under single fault

[Ralph McDiarmid]

" This incident serves to remind us that in our field of product safety, we
require the product to be safe even in the event of a failure of any single
component. "

Maybe better to claim "product safety compliant under any single-fault".
It's quite a reach and perhaps not appropriate to claim something is safe,
unless you accompany that claim with your definition of safe, which may
differ from mine.  

Ralph

-Original Message-
From: Richard Nute  
Sent: Wednesday, October 11, 2023 12:41 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] safety under single fault

Hello from Bend, Oregon:

On September 4, 2022, a plane carrying 10 people crashed into Puget Sound's
Mutiny Bay near Whidbey Island.  The National Transportation Safety Board,
which investigated the crash, said Thursday that a single component of a
critical flight control system failed, causing an unrecoverable,
near-vertical descent.  

"The Mutiny Bay accident is an incredibly painful reminder that a single
point of failure can lead to catastrophe in our skies," NTSB Chair Jennifer
Homendy said in a news release.

Nate Bingham, who is representing the Ludwigs' families, said the plane
crashed because of "an antiquated design with a single point of failure."

Details:
https://apnews.com/article/seaplane-crash-puget-sound-san-juan-island-10-kil
led-531d4e5a2dfed65370294243b1a07157

This incident serves to remind us that in our field of product safety, we
require the product to be safe even in the event of a failure of any single
component.  

Best regards,
Rich

 

Boats from the U.S. Coast Guard and Kitsap County Sheriff's Office search
the area off Whidbey Island north of Seattle on Sept. 5, 2022, where a
chartered floatplane crashed the day before, killing 10 people. Stephen
Brashear/AP file






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Re: [PSES] safety under single fault

[Ralph McDiarmid]

I suppose same can be said for any Google search done on the job site.

-Original Message-
From: Mark Gandler  
Sent: Wednesday, October 11, 2023 2:28 PM
To: rmm.priv...@gmail.com; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] safety under single fault

Just a simple reminder, especially if anyone uses their employer or private
business devices to use AI tools: the information used for questions
immediately and forever becomes public property.

-Original Message-
From: Ralph McDiarmid 
Sent: Wednesday, October 11, 2023 2:08 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] safety under single fault

Here's what ChatGPT 3.5 says about fault-tolerance and general aviation
aircraft:

Fault-tolerance systems in general aviation aircraft can enhance safety, but
their inclusion is not mandatory for all such aircraft.  The need for
fault-tolerance systems depends on several factors, including the type of
aircraft, its complexity, and its intended use.

General aviation aircraft range from small, simple, single-engine planes to
larger, more complex, and technologically advanced aircraft. The level of
fault tolerance required often correlates with the complexity and mission
profile of the aircraft.  Here are some considerations:

Simple Aircraft: Small, single-engine general aviation aircraft often have
basic systems and controls. While they are not required to have elaborate
fault-tolerance systems, safety measures such as redundant flight
instruments and simple backup systems might be included.

Advanced Aircraft: More complex general aviation aircraft, such as
multi-engine planes or those equipped with advanced avionics, might
incorporate redundant systems or fail-safe features to improve safety. For
example, they might have redundant power sources, dual avionics systems, or
backup instruments.

Mission Profile: The intended use of the aircraft can also influence the
need for fault-tolerance systems. Aircraft used for critical missions, like
air ambulance or search and rescue, might have more robust safety features
to ensure that they can operate in adverse conditions.

Regulations: Aviation authorities like the FAA in the United States set
safety standards for various aircraft categories. These standards may
dictate the inclusion of certain safety features, depending on the
aircraft's size and use. For example, Part 23 of the Federal Aviation
Regulations (FAR) in the U.S. specifies the airworthiness standards for
general aviation aircraft.

In summary, while fault-tolerance systems can enhance the safety of general
aviation aircraft, their inclusion is not a blanket requirement for all such
aircraft. It depends on factors such as the aircraft's complexity, mission
profile, and regulatory standards. Pilots and aircraft operators should
adhere to relevant safety regulations and guidelines, which may vary from
one country to another.


Ralph

-Original Message-
From: Richard Nute 
Sent: Wednesday, October 11, 2023 12:41 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] safety under single fault

Hello from Bend, Oregon:

On September 4, 2022, a plane carrying 10 people crashed into Puget Sound's
Mutiny Bay near Whidbey Island.  The National Transportation Safety Board,
which investigated the crash, said Thursday that a single component of a
critical flight control system failed, causing an unrecoverable,
near-vertical descent.

"The Mutiny Bay accident is an incredibly painful reminder that a single
point of failure can lead to catastrophe in our skies," NTSB Chair Jennifer
Homendy said in a news release.

Nate Bingham, who is representing the Ludwigs' families, said the plane
crashed because of "an antiquated design with a single point of failure."

Details:
https://apnews.com/article/seaplane-crash-puget-sound-san-juan-island-10-kil
led-531d4e5a2dfed65370294243b1a07157

This incident serves to remind us that in our field of product safety, we
require the product to be safe even in the event of a failure of any single
component.

Best regards,
Rich



Boats from the U.S. Coast Guard and Kitsap County Sheriff's Office search
the area off Whidbey Island north of Seattle on Sept. 5, 2022, where a
chartered floatplane crashed the day before, killing 10 people. Stephen
Brashear/AP file






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Re: [PSES] safety under single fault

[Ralph McDiarmid]

Obviously, even an "antiquated design with a single point of failure", gets
an air worthiness certificate by the FAA.   However, LFP batteries need a
fault-tolerant battery management system and tons of testing called out in
UL1973 3rd edition.  Not all aircraft need single-fault tolerance.

I suspect that a large majority of aircraft incident reports are a result of
pilot error, nothing to do with the aircraft its avionics.

Ralph

-Original Message-
From: Richard Nute  
Sent: Wednesday, October 11, 2023 12:41 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] safety under single fault

Hello from Bend, Oregon:

On September 4, 2022, a plane carrying 10 people crashed into Puget Sound's
Mutiny Bay near Whidbey Island.  The National Transportation Safety Board,
which investigated the crash, said Thursday that a single component of a
critical flight control system failed, causing an unrecoverable,
near-vertical descent.  

"The Mutiny Bay accident is an incredibly painful reminder that a single
point of failure can lead to catastrophe in our skies," NTSB Chair Jennifer
Homendy said in a news release.

Nate Bingham, who is representing the Ludwigs' families, said the plane
crashed because of "an antiquated design with a single point of failure."

Details:
https://apnews.com/article/seaplane-crash-puget-sound-san-juan-island-10-kil
led-531d4e5a2dfed65370294243b1a07157

This incident serves to remind us that in our field of product safety, we
require the product to be safe even in the event of a failure of any single
component.  

Best regards,
Rich

 

Boats from the U.S. Coast Guard and Kitsap County Sheriff's Office search
the area off Whidbey Island north of Seattle on Sept. 5, 2022, where a
chartered floatplane crashed the day before, killing 10 people. Stephen
Brashear/AP file






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Re: [PSES] safety under single fault

[Ralph McDiarmid]

Here's what ChatGPT 3.5 says about fault-tolerance and general aviation
aircraft:

Fault-tolerance systems in general aviation aircraft can enhance safety, but
their inclusion is not mandatory for all such aircraft.  The need for
fault-tolerance systems depends on several factors, including the type of
aircraft, its complexity, and its intended use.

General aviation aircraft range from small, simple, single-engine planes to
larger, more complex, and technologically advanced aircraft. The level of
fault tolerance required often correlates with the complexity and mission
profile of the aircraft.  Here are some considerations:

Simple Aircraft: Small, single-engine general aviation aircraft often have
basic systems and controls. While they are not required to have elaborate
fault-tolerance systems, safety measures such as redundant flight
instruments and simple backup systems might be included.

Advanced Aircraft: More complex general aviation aircraft, such as
multi-engine planes or those equipped with advanced avionics, might
incorporate redundant systems or fail-safe features to improve safety. For
example, they might have redundant power sources, dual avionics systems, or
backup instruments.

Mission Profile: The intended use of the aircraft can also influence the
need for fault-tolerance systems. Aircraft used for critical missions, like
air ambulance or search and rescue, might have more robust safety features
to ensure that they can operate in adverse conditions.

Regulations: Aviation authorities like the FAA in the United States set
safety standards for various aircraft categories. These standards may
dictate the inclusion of certain safety features, depending on the
aircraft's size and use. For example, Part 23 of the Federal Aviation
Regulations (FAR) in the U.S. specifies the airworthiness standards for
general aviation aircraft.

In summary, while fault-tolerance systems can enhance the safety of general
aviation aircraft, their inclusion is not a blanket requirement for all such
aircraft. It depends on factors such as the aircraft's complexity, mission
profile, and regulatory standards. Pilots and aircraft operators should
adhere to relevant safety regulations and guidelines, which may vary from
one country to another.


Ralph

-Original Message-
From: Richard Nute  
Sent: Wednesday, October 11, 2023 12:41 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] safety under single fault

Hello from Bend, Oregon:

On September 4, 2022, a plane carrying 10 people crashed into Puget Sound's
Mutiny Bay near Whidbey Island.  The National Transportation Safety Board,
which investigated the crash, said Thursday that a single component of a
critical flight control system failed, causing an unrecoverable,
near-vertical descent.  

"The Mutiny Bay accident is an incredibly painful reminder that a single
point of failure can lead to catastrophe in our skies," NTSB Chair Jennifer
Homendy said in a news release.

Nate Bingham, who is representing the Ludwigs' families, said the plane
crashed because of "an antiquated design with a single point of failure."

Details:
https://apnews.com/article/seaplane-crash-puget-sound-san-juan-island-10-kil
led-531d4e5a2dfed65370294243b1a07157

This incident serves to remind us that in our field of product safety, we
require the product to be safe even in the event of a failure of any single
component.  

Best regards,
Rich

 

Boats from the U.S. Coast Guard and Kitsap County Sheriff's Office search
the area off Whidbey Island north of Seattle on Sept. 5, 2022, where a
chartered floatplane crashed the day before, killing 10 people. Stephen
Brashear/AP file






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Website:  https://

Re: [PSES] AI & Regulatory Compliance

[Ralph McDiarmid]

That analogy was not intended, and I’m merely trying to point out that AI is 
here to stay and is expected to become a more useful tool in our industry as it 
has been proven to be in the medical profession.

 

From: Douglas Nix  
Sent: Tuesday, October 10, 2023 1:03 PM
To: rmm.priv...@gmail.com
Cc: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] AI & Regulatory Compliance

 

You cannot compare ChatGPT to a medical AI that has been tailored for a 
specific task like medical image analysis. That’s like saying a 1968 Mini 
Cooper and Dodge 440 HEMI Charger are comparable because they are both cars. 
Nope.

 

Using ChatGPT to summarize a paper, produce an abstract from uploaded text, or 
produce a set of points as a starting point is perfectly fine. You are giving 
the software the specific input material from which to generate the output. You 
cannot ask it research questions an expect a valid response because ChatGPT has 
no parameters for correctness. It only wants to give you a plausible sounding 
answer. It will give you an authoritative answer with no reference to anything 
resembling truth.

 

Doug Nix

d...@mac.com <mailto:d...@mac.com> 

http://www.dougnix.net

(519) 729-5704

 

"All animals except man know that the ultimate joy of life is to enjoy it."  -- 
Samuel Butler

 

 





On Oct 10, 2023, at 14:15, Ralph McDiarmid mailto:rmm.priv...@gmail.com> > wrote:

 

Physicians have used AI (expert systems) in their offices for many years as a 
tool to help them diagnose a problem more accurately and will greater speed.  
It’s a tool to speed productivity, and that’s how I use it today.

 


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Re: [PSES] AI & Regulatory Compliance

[Ralph McDiarmid]

Which is another way of saying that ChatGPT and other similar AI are tools used 
by professionals to assist with improving their productivity, but not something 
to be used in lieu of a professional.  (at least not in this decade).  That 
time may come, but I suspect engineering jobs are safe for the foreseeable 
future.

 

Ralph

 

From: Dan Roman <0d75e04ed751-dmarc-requ...@listserv.ieee.org> 
Sent: Tuesday, October 10, 2023 10:51 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] AI & Regulatory Compliance

 

Other than playing around with text queries the most useful thing I have found 
either Chat GPT or Bard (the two I have used regularly) good for is Python 
coding.  While I can never take the code as is, it does offer tips on libraries 
that I did not even know existing to more easily perform a task.  I think 
others have hit on a similar use case for presentations and other output.  The 
AI can be useful to give you some ideas that you might not have already had and 
help you think about a problem or task in a different way  As with my Python 
example, you can’t just take what it gives you, you have to do the work and 
perhaps use some clues or ideas from the AI.

 

Dan

 

 

From: Brian Gregory [mailto:brian_greg...@netzero.net] 
Sent: Tuesday, October 10, 2023 12:16 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] AI & Regulatory Compliance

 

 

Chat GPT is essentially a BS generator.  A very smart friend, a very successful 
entrepreneur, finds it quite useful for writing add copy, which I think proved 
my point.

 

The one time I tried challenging GPT with a question on power factor with 
generator convention (where positive power generation is represented as 
negative), it failed miserably. 

 

Echoing Dan's point;  what other AI's are more suitable to electrical 
engineering concepts, including testing and reviewing lists of standards?  If I 
had to pick one question for an AI I think might qualify would be:  " does this 
requirement apply to a residential unit? "  

 

 Colorado Brian 



-- Forwarded Message --
From: Dan Roman <0d75e04ed751-dmarc-requ...@listserv.ieee.org 
 >
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] AI & Regulatory Compliance
Date: Mon, 9 Oct 2023 22:21:26 -0400

Has anyone tried feeding a standard or set of standards, into Chat GPT for 
example, and ask it product construction or testing questions? I've seen demos 
of Chat GPT digesting complex equipment manuals and being able to generate what 
amounts to a quick start guide and answer questions about operating or 
servicing the equipment. I can't try this with the free version.

--

Dan Roman

danp...@verizon.net  

On Oct 9, 2023, at 7:31 PM, Douglas Powell mailto:doug...@gmail.com> > wrote: 

I've done some playing around with ChatGPT, Claude.AI, Perplexity.AI, BIng 
Chatbot, and a few others.  

 

My first test was to see if these Large Language Models (LLM) could accurately 
answer questions where I feel I have good expertise, such as "How do I select a 
complete list of safety-critical components using UL XYZ?" or "Write a 
comprehensive Test Protocol for  a  kitchen appliance using IEC 
60335-*X-X." For the most part they failed in several points when the questions 
got just a little technical.  Sometimes, I would challenge the AI on answers it 
gave, and occasionally it would backpedal. 

 

Even so, I do find them useful as a starting point for writing White Papers and 
PowerPoint slides or procedural documents at the paragraph-level, for internal 
distribution.  Try prompting an AI to generate 20 PowerPoint slides for basic 
Risk Assessment Training using ISO 31000.  In every case however, I only use AI 
to do the initial grunt work and then personally edit everything for accuracy. 
So far, my favorite is Perplexity.AI because it gives attribution of sources 
for all its answers, second place is possibly Claude.AI.  And been using 
QuillBot.AI to check grammar and paraphrase complex paragraphs.  But when it 
comes to life-safety issues, I will always be very careful and check the work.

 

Incidentally, I've tried a few fun things as a lunchtime diversion.  I'll 
prompt the AI with something like: "Entropy simply isn’t what it used to be."  
or "Schrödinger’s cat walks into a bar. And doesn’t." And of course the AI 
never gets the joke.  

 

-Doug

 

Douglas E Powell

Laporte, Colorado, USA

  LinkedIn

 

(UTC-06:00, US-MDT)

 

 

 

 

 

On Fri, Oct 6, 2023 at 3:59 PM Regan Arndt mailto:reganar...@gmail.com> > wrote:

Greetings fellow members,

Our industry will not be immune to this new era of AI technology and want to 
bring up this topic again to obtain some more insight from the forum into:

"How do you think AI will play a future role in ou

Re: [PSES] AI & Regulatory Compliance

[Ralph McDiarmid]

I would add that about 9 out of 10 power engineers I’ve worked with over the 
years are equally confused with the “convention” of power factor and sign 
convention of real and reactive power flow.  Microelectronics engineers also 
often get the sign convention wrong when considering current source or sink 
from a logic gate or an op-amp.   I wouldn’t beat up on ChatGPT for struggling 
with that very specific topic.

 

Ralph

 

From: Brian Gregory  
Sent: Tuesday, October 10, 2023 9:16 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] AI & Regulatory Compliance

 

 

Chat GPT is essentially a BS generator.  A very smart friend, a very successful 
entrepreneur, finds it quite useful for writing add copy, which I think proved 
my point.

 

The one time I tried challenging GPT with a question on power factor with 
generator convention (where positive power generation is represented as 
negative), it failed miserably. 

 

Echoing Dan's point;  what other AI's are more suitable to electrical 
engineering concepts, including testing and reviewing lists of standards?  If I 
had to pick one question for an AI I think might qualify would be:  " does this 
requirement apply to a residential unit? "  

 

 Colorado Brian 



-- Forwarded Message --
From: Dan Roman <0d75e04ed751-dmarc-requ...@listserv.ieee.org 
 >
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] AI & Regulatory Compliance
Date: Mon, 9 Oct 2023 22:21:26 -0400

Has anyone tried feeding a standard or set of standards, into Chat GPT for 
example, and ask it product construction or testing questions? I've seen demos 
of Chat GPT digesting complex equipment manuals and being able to generate what 
amounts to a quick start guide and answer questions about operating or 
servicing the equipment. I can't try this with the free version.

--

Dan Roman

danp...@verizon.net  

On Oct 9, 2023, at 7:31 PM, Douglas Powell mailto:doug...@gmail.com> > wrote: 

I've done some playing around with ChatGPT, Claude.AI, Perplexity.AI, BIng 
Chatbot, and a few others.  

 

My first test was to see if these Large Language Models (LLM) could accurately 
answer questions where I feel I have good expertise, such as "How do I select a 
complete list of safety-critical components using UL XYZ?" or "Write a 
comprehensive Test Protocol for  a  kitchen appliance using IEC 
60335-*X-X." For the most part they failed in several points when the questions 
got just a little technical.  Sometimes, I would challenge the AI on answers it 
gave, and occasionally it would backpedal. 

 

Even so, I do find them useful as a starting point for writing White Papers and 
PowerPoint slides or procedural documents at the paragraph-level, for internal 
distribution.  Try prompting an AI to generate 20 PowerPoint slides for basic 
Risk Assessment Training using ISO 31000.  In every case however, I only use AI 
to do the initial grunt work and then personally edit everything for accuracy. 
So far, my favorite is Perplexity.AI because it gives attribution of sources 
for all its answers, second place is possibly Claude.AI.  And been using 
QuillBot.AI to check grammar and paraphrase complex paragraphs.  But when it 
comes to life-safety issues, I will always be very careful and check the work.

 

Incidentally, I've tried a few fun things as a lunchtime diversion.  I'll 
prompt the AI with something like: "Entropy simply isn’t what it used to be."  
or "Schrödinger’s cat walks into a bar. And doesn’t." And of course the AI 
never gets the joke.  

 

-Doug

 

Douglas E Powell

Laporte, Colorado, USA

  LinkedIn

 

(UTC-06:00, US-MDT)

 

 

 

 

 

On Fri, Oct 6, 2023 at 3:59 PM Regan Arndt mailto:reganar...@gmail.com> > wrote:

Greetings fellow members,

Our industry will not be immune to this new era of AI technology and want to 
bring up this topic again to obtain some more insight from the forum into:

"How do you think AI will play a future role in our Regulatory compliance 
world?"

 

I can see some real benefits to this when applying it to a risk assessment, EMC 
redesign including change out of critical components, & possibly to help 
support engineering judgments in lieu of testing (i.e. temperature modeling), 
etc.…though I think we would have to include the usage of AI as one of the 
potential risks in the risk assessment. lol

UL touched base on this topic during their UL Innovations summit held in 
Fremont, CA yesterday.

I know there is the ISO/IEC DTR 5469 in development, but this appears, I 
believe, to only address functional safety of the AI systems in question, and 
not addressing AI in normal compliance assessments for products under the 
category of laboratory, IT, audio, etc.

Also, is there someone out there that will be speaking to this during the 2024 
ISPCE in Chicago

Re: [PSES] AI & Regulatory Compliance

[Ralph McDiarmid]

Very interesting demo of its capabilities.

 

I am wondering if the $20 per month version of ChatGPT might be worthwhile.

 

Ralph

 

From: Dan Roman <0d75e04ed751-dmarc-requ...@listserv.ieee.org> 
Sent: Monday, October 9, 2023 7:21 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] AI & Regulatory Compliance

 

Has anyone tried feeding a standard or set of standards, into Chat GPT for 
example, and ask it product construction or testing questions? I've seen demos 
of Chat GPT digesting complex equipment manuals and being able to generate what 
amounts to a quick start guide and answer questions about operating or 
servicing the equipment. I can't try this with the free version.

--

Dan Roman

danp...@verizon.net  

On Oct 9, 2023, at 7:31 PM, Douglas Powell mailto:doug...@gmail.com> > wrote:

I've done some playing around with ChatGPT, Claude.AI, Perplexity.AI, BIng 
Chatbot, and a few others.  

 

My first test was to see if these Large Language Models (LLM) could accurately 
answer questions where I feel I have good expertise, such as "How do I select a 
complete list of safety-critical components using UL XYZ?" or "Write a 
comprehensive Test Protocol for  a  kitchen appliance using IEC 
60335-*X-X." For the most part they failed in several points when the questions 
got just a little technical.  Sometimes, I would challenge the AI on answers it 
gave, and occasionally it would backpedal. 

 

Even so, I do find them useful as a starting point for writing White Papers and 
PowerPoint slides or procedural documents at the paragraph-level, for internal 
distribution.  Try prompting an AI to generate 20 PowerPoint slides for basic 
Risk Assessment Training using ISO 31000.  In every case however, I only use AI 
to do the initial grunt work and then personally edit everything for accuracy. 
So far, my favorite is Perplexity.AI because it gives attribution of sources 
for all its answers, second place is possibly Claude.AI.  And been using 
QuillBot.AI to check grammar and paraphrase complex paragraphs.  But when it 
comes to life-safety issues, I will always be very careful and check the work.

 

Incidentally, I've tried a few fun things as a lunchtime diversion.  I'll 
prompt the AI with something like: "Entropy simply isn’t what it used to be."  
or "Schrödinger’s cat walks into a bar. And doesn’t." And of course the AI 
never gets the joke.  

 

-Doug

 

Douglas E Powell

Laporte, Colorado, USA

  LinkedIn

 

(UTC-06:00, US-MDT)

 

 

 

 

 

On Fri, Oct 6, 2023 at 3:59 PM Regan Arndt mailto:reganar...@gmail.com> > wrote:

Greetings fellow members,

Our industry will not be immune to this new era of AI technology and want to 
bring up this topic again to obtain some more insight from the forum into:

"How do you think AI will play a future role in our Regulatory compliance 
world?"

 

I can see some real benefits to this when applying it to a risk assessment, EMC 
redesign including change out of critical components, & possibly to help 
support engineering judgments in lieu of testing (i.e. temperature modeling), 
etc.…though I think we would have to include the usage of AI as one of the 
potential risks in the risk assessment. lol

UL touched base on this topic during their UL Innovations summit held in 
Fremont, CA yesterday.

I know there is the ISO/IEC DTR 5469 in development, but this appears, I 
believe, to only address functional safety of the AI systems in question, and 
not addressing AI in normal compliance assessments for products under the 
category of laboratory, IT, audio, etc.

Also, is there someone out there that will be speaking to this during the 2024 
ISPCE in Chicago next May? Perhaps there should be an IEEE PSES technical 
committee created for this?

Side note: Nordcloud puts out a good summary blog on this:  
 
https://nordcloud.com/blog/how-ai-can-help-you-obtain-regulatory-compliance/

There are other AI blogs out there in the ether but more tuned for the 
financial sector and other industries….

Looking forward to the discussion. 

 

P.S.

I am now the Chair for the IEEE PSES Risk assessment technical committee and am 
looking for any volunteers to join our group. This topic will be one to discuss 
soon within our group. Please email me at   
regan.ar...@ieee.org or   reganar...@gmail.com if 
you are interested in joining.

Cheers!

Regan Arndt


  _  


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to All 
emc-pstc postings are archived and searchable on the web at: 
https://www.mail-archive.com/emc-pstc@listserv.ieee.org/ 

Website: https://ewh.ieee.org/soc/pses/   
Instructions: https://ewh.ieee.org/soc/pses/l

Re: [PSES] AI & Regulatory Compliance

[Ralph McDiarmid]

“Even so, I do find them useful as a starting point for writing White Papers 
and PowerPoint slides or procedural documents at the paragraph-level, for 
internal distribution. “

 

I do the same.  It’s useful now, even though not perfect, and AI is only going 
to get better and that will happen rapidly.

 

Physicians have used AI (expert systems) in their offices for many years as a 
tool to help them diagnose a problem more accurately and will greater speed.  
It’s a tool to speed productivity, and that’s how I use it today.

 

Ralph

 

From: Douglas Powell  
Sent: Monday, October 9, 2023 4:30 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] AI & Regulatory Compliance

 

I've done some playing around with ChatGPT, Claude.AI, Perplexity.AI, BIng 
Chatbot, and a few others.  

 

My first test was to see if these Large Language Models (LLM) could accurately 
answer questions where I feel I have good expertise, such as "How do I select a 
complete list of safety-critical components using UL XYZ?" or "Write a 
comprehensive Test Protocol for  a  kitchen appliance using IEC 
60335-*X-X." For the most part they failed in several points when the questions 
got just a little technical.  Sometimes, I would challenge the AI on answers it 
gave, and occasionally it would backpedal. 

 

Even so, I do find them useful as a starting point for writing White Papers and 
PowerPoint slides or procedural documents at the paragraph-level, for internal 
distribution.  Try prompting an AI to generate 20 PowerPoint slides for basic 
Risk Assessment Training using ISO 31000.  In every case however, I only use AI 
to do the initial grunt work and then personally edit everything for accuracy. 
So far, my favorite is Perplexity.AI because it gives attribution of sources 
for all its answers, second place is possibly Claude.AI.  And been using 
QuillBot.AI to check grammar and paraphrase complex paragraphs.  But when it 
comes to life-safety issues, I will always be very careful and check the work.

 

Incidentally, I've tried a few fun things as a lunchtime diversion.  I'll 
prompt the AI with something like: "Entropy simply isn’t what it used to be."  
or "Schrödinger’s cat walks into a bar. And doesn’t." And of course the AI 
never gets the joke.  

 

-Doug

 

Douglas E Powell

Laporte, Colorado, USA

  LinkedIn

 

(UTC-06:00, US-MDT)

 

 

 

 

 

On Fri, Oct 6, 2023 at 3:59 PM Regan Arndt mailto:reganar...@gmail.com> > wrote:

Greetings fellow members,

Our industry will not be immune to this new era of AI technology and want to 
bring up this topic again to obtain some more insight from the forum into:

"How do you think AI will play a future role in our Regulatory compliance 
world?"

 

I can see some real benefits to this when applying it to a risk assessment, EMC 
redesign including change out of critical components, & possibly to help 
support engineering judgments in lieu of testing (i.e. temperature modeling), 
etc.…though I think we would have to include the usage of AI as one of the 
potential risks in the risk assessment. lol

UL touched base on this topic during their UL Innovations summit held in 
Fremont, CA yesterday.

I know there is the ISO/IEC DTR 5469 in development, but this appears, I 
believe, to only address functional safety of the AI systems in question, and 
not addressing AI in normal compliance assessments for products under the 
category of laboratory, IT, audio, etc.

Also, is there someone out there that will be speaking to this during the 2024 
ISPCE in Chicago next May? Perhaps there should be an IEEE PSES technical 
committee created for this?

Side note: Nordcloud puts out a good summary blog on this:  
 
https://nordcloud.com/blog/how-ai-can-help-you-obtain-regulatory-compliance/

There are other AI blogs out there in the ether but more tuned for the 
financial sector and other industries….

Looking forward to the discussion. 

 

P.S.

I am now the Chair for the IEEE PSES Risk assessment technical committee and am 
looking for any volunteers to join our group. This topic will be one to discuss 
soon within our group. Please email me at   
regan.ar...@ieee.org or   reganar...@gmail.com if 
you are interested in joining.

Cheers!

Regan Arndt


  _  


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to All 
emc-pstc postings are archived and searchable on the web at: 
https://www.mail-archive.com/emc-pstc@listserv.ieee.org/ 

Website: https://ewh.ieee.org/soc/pses/   
Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to 
unsubscribe)  
List rules: https://ewh.ieee.org/soc/pses/listrules.html 

For help, s

Re: [PSES] AW: [PSES] Directives that require the CE Marking

[Ralph McDiarmid]

I agree that tools like ChatGPT have a long way to go before their response can 
be trusted without question, but the response below is from the free version.  
The $20 a month version might provide a clearer answer.  I use ChatGPT as a 
starting point for topics I have some familiarity with, then I drill down on 
the details.

 

I asked ChatGPT “under what conditions should I not apply the CE Mark ?”, and 
it answered:

 

=

The CE mark is a certification mark that indicates conformity with health, 
safety, and environmental protection standards for products sold within the 
European Economic Area (EEA).  It demonstrates that a product complies with the 
relevant EU directives and regulations. However, there are certain conditions 
or situations where you should not apply the CE mark:

1.  Non-conforming products: If your product does not meet the essential 
requirements or standards specified by the relevant EU directives or 
regulations, you should not apply the CE mark. It is essential to ensure that 
your product complies with all applicable requirements before affixing the CE 
mark.
2.  Non-covered products: Some products or product categories may not be 
covered by specific EU directives or regulations, and therefore, the CE mark 
may not be applicable to them. Always check whether your product falls under 
any relevant EU legislation before considering the CE mark.
3.  Self-declaration without applicable legislation: In some cases, a 
manufacturer may incorrectly self-declare conformity and affix the CE mark to a 
product without any applicable EU directive or regulation. This is not allowed, 
and the CE mark should only be applied when there is clear and relevant 
legislation to comply with.
4.  Non-EEA sales: The CE mark is primarily intended for products intended 
for sale within the EEA. If your product is not intended for the EEA market, 
applying the CE mark may not be necessary. However, you should comply with the 
regulatory requirements of the specific market where you intend to sell your 
product.
5.  Unauthorized use: The CE mark should only be applied by manufacturers 
or authorized representatives who have fulfilled the necessary conformity 
assessment procedures and legal obligations. Unauthorized use of the CE mark is 
not allowed and can result in legal consequences.
6.  False or misleading information: Providing false or misleading 
information, documentation, or test results to obtain the CE mark is illegal 
and should not be done under any circumstances.

 

It's crucial to consult with regulatory authorities, experts, or legal counsel 
knowledgeable about the specific product and its applicable regulations to 
ensure compliance with CE marking requirements. Incorrectly applying the CE 
mark can lead to legal consequences, including fines and product recalls.

==

 

Ralph

 

From: Charlie Blackham  
Sent: Saturday, October 7, 2023 1:17 AM
To: rmm.priv...@gmail.com; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] AW: [PSES] Directives that require the CE Marking

 

A nice example of why ChatGPT won’t put us all out of a job just yet 😊

 

Point 9 is wrong – you may not use the CE mark to demonstrate compliance with a 
“non CE marking” Directive, that is one that does not contain the provision for 
CE marking within its Articles or Annexes

 

Point 3 does not make it clear that the Directive also includes products that 
are “likely, under reasonably foreseeable conditions, to be used by consumers 
even if not intended for them” – an example of this would be something like a 
corporate branded battery pack phone charger which is supplied only on a B2B 
basis, but is likely to be taken home by the recipient

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Tel: +44 (0)7946 624317

Web: https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 

From: Ralph McDiarmid mailto:rmm.priv...@gmail.com> > 
Sent: Friday, October 6, 2023 10:59 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] AW: [PSES] Directives that require the CE Marking

 

Here’s what ChatGPT told me about this directive:

 

The General Product Safety Directive (2001/95/EC) in the European Union (EU) is 
a legal framework designed to ensure the safety of consumer products placed on 
the EU market. It sets out general requirements for the safety of products, 
regardless of whether specific product safety regulations exist for them. Here 
are key aspects of the General Product Safety Directive (GPSD):

1.  Scope: The GPSD applies to all consumer products, excluding food, 
pharmaceuticals, medical devices, cosmetics, and chemicals, which are covered 
by other specific regulations.
2.  Safety Requirement: The primary obje

Re: [PSES] AW: [PSES] Directives that require the CE Marking

[Ralph McDiarmid]

Here’s what ChatGPT told me about this directive:

 

The General Product Safety Directive (2001/95/EC) in the European Union (EU)
is a legal framework designed to ensure the safety of consumer products
placed on the EU market. It sets out general requirements for the safety of
products, regardless of whether specific product safety regulations exist
for them. Here are key aspects of the General Product Safety Directive
(GPSD):

1.  Scope: The GPSD applies to all consumer products, excluding food,
pharmaceuticals, medical devices, cosmetics, and chemicals, which are
covered by other specific regulations.
2.  Safety Requirement: The primary objective of the GPSD is to ensure
that products placed on the market are safe for consumers when used under
normal or reasonably foreseeable conditions. Manufacturers and distributors
have an obligation to provide safe products.
3.  Definition of Consumer Products: The directive defines "consumer
products" broadly to encompass any product intended for consumers, including
both new and second-hand products.
4.  Obligations of Economic Operators: Economic operators, including
manufacturers, importers, and distributors, must ensure that products they
place on the market are safe. They are responsible for assessing and
managing risks, monitoring product safety, and taking corrective actions if
safety issues arise.
5.  Traceability: Economic operators must be able to trace the origin of
the products they handle and, if necessary, inform the relevant authorities
and consumers about safety issues or recalls.
6.  Rapid Alert System: The GPSD establishes a Rapid Alert System for
Non-Food (RAPEX) to facilitate the rapid exchange of information about
dangerous products among EU member states and the European Commission. This
system helps to ensure that dangerous products are quickly removed from the
market.
7.  Market Surveillance: EU member states are responsible for carrying
out market surveillance activities to ensure compliance with the GPSD. They
can take measures such as conducting inspections, ordering recalls, or
imposing fines for non-compliance.
8.  Cooperation with Other EU Legislation: The GPSD complements other EU
product safety regulations, such as the Toy Safety Directive or the
Machinery Directive. In cases where specific product safety legislation
exists, that legislation takes precedence.
9.  CE Marking: While the GPSD does not require products to bear the CE
marking (a conformity marking indicating compliance with EU safety
standards), manufacturers may choose to use it to demonstrate compliance
with the directive.
10. Harmonized Standards: Manufacturers can use harmonized European
standards to demonstrate compliance with the GPSD's safety requirements.

The General Product Safety Directive plays a crucial role in protecting
consumers within the EU by establishing a baseline level of safety for a
wide range of consumer products. It encourages manufacturers and other
economic operators to ensure that their products are safe for use and allows
for swift action in the event of safety concerns. It is important to note
that the GPSD is subject to updates and amendments to align with changing
safety requirements and technological advancements.

 

Ralph

 

From: Dürrer Bernd  
Sent: Tuesday, September 19, 2023 6:44 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] AW: [PSES] Directives that require the CE Marking

 

Hello Brian,

 

in lack of any more specific EU Directive, a product will be in the scope of
the General Product Safety Directive 2001/95/EC (
 Consolidated TEXT: 32001L0095 — EN — 01.01.2010 (europa.eu))
that covers any product intended for consumers. As far as I know, the GPSD
does neither require a CE Declaration of Conformity, nor CE marking on the
product. An overview of EU Directives and applicable harmonized standards
may be found at
 Harmonised Standards (europa.eu).

 

Is the product intended to be permanently connected to a potable water
supply? If yes, national regulations of EU member countries may apply.

 

Kind regards,

 

Bernd

 

Von: Brian Kunde mailto:bkundew...@gmail.com> > 
Gesendet: Dienstag, 19. September 2023 15:31
An: EMC-PSTC@LISTSERV.IEEE.ORG  
Betreff: [PSES] Directives that require the CE Marking

 


[EXTERNAL E-MAIL] This email originated from outside of the organization. Do
not click links or open attachments unless you recognize the sender. 



I have a non-electrical benchtop product that holds a piece of sandpaper
while slowly running water over the sandpaper. The only connection to this
product is a water supply at normal water supply pressure.  The User holds
the item they want to sand in their hand and rubs it back and forth on the
s

Re: [PSES] KC certification

[Ralph McDiarmid]

Here’s what ChatGPT recommends:

 

In South Korea, to obtain KC (Korea Certification) registration for a Class III 
radio device, you will need to follow a specific process to ensure your product 
complies with the country's regulatory requirements.  

 

Here are the general steps you should take:

 

1.  Determine the Classification: Class III radio devices are typically 
low-power and low-risk devices. Ensure that your radio device falls within this 
classification as defined by South Korean regulations.

 

2.  Identify Applicable Standards: Research and identify the applicable 
Korean standards and technical requirements that your radio device must meet. 
These standards may include electromagnetic compatibility (EMC) and radio 
frequency (RF) requirements.

 

3.  Appoint a Local Representative: As a foreign manufacturer, you may need 
to appoint a local representative in South Korea who will be responsible for 
communicating with the relevant authorities and ensuring compliance with 
regulatory requirements.

 

4.  Testing and Certification: Your radio device must undergo testing by a 
recognized Korean testing laboratory. The laboratory will assess the device's 
compliance with the applicable standards. If the device passes the tests, you 
will receive a test report.

 

5.  Prepare Documentation: Compile all necessary documentation, including 
the test report, technical documentation, user manuals, and any other relevant 
information required by the certification process.

 

6.  Application Submission: Submit your application for KC certification to 
the Korea Communications Commission (KCC) or another relevant regulatory 
authority, depending on the specific requirements for your radio device.

 

7.  Review and Approval: The regulatory authority will review your 
application and supporting documentation. If your device meets all the 
requirements, it will be granted KC certification.

 

8.  Labeling: Once your device is certified, you will be required to affix 
the KC certification label to your product before it is sold in South Korea.

 

9.  Ongoing Compliance: Keep your product in compliance with the Korean 
regulations and standards. This may involve regular testing and ensuring that 
any modifications to the product are also certified.

 

Please note that this is an overview and the specific requirements and 
procedures for obtaining KC certification for a Class III radio device may vary 
based on the nature of the product and any updates to Korean regulations.  It 
is essential to consult with a local expert or a legal representative in South 
Korea who specializes in product certification to navigate the process 
effectively and ensure compliance with the latest requirements.

 

 

From: peterh...@aol.com <06cee064502d-dmarc-requ...@listserv.ieee.org> 
Sent: Thursday, October 5, 2023 9:09 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] KC certification

 

Hello group,

I have a client who has recently managed to get accreditation from Korea for 
their EMI lab. Now they want to submit their first product and get KC 
registration under Broadcasting and Communication Equipment. The product is a 
simple Class III without any radio. They have all the documents ready but don’t 
know where to submit. Has anyone submitted a project for KC here that can give 
me a pointer please?

Thank you
Peter

 

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Re: [PSES] SV: [PSES] Radio receivers under RED? Yes

[Ralph McDiarmid]

I thought the EMCD would be sufficient for radio and television receivers.  To 
include them within scope of the RED seems an overreach. 

 

From: Charlie Blackham  
Sent: Thursday, October 5, 2023 12:38 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] SV: [PSES] Radio receivers under RED? Yes

 

Television and radio receivers are within scope of RED 😊 (they weren’t under 
R&TTE)

 

 <mailto:am...@westin-emission.no> @Amund Westin – you should be careful 
determining whether your item is “test equipment” or “radio equipment” – 
wideband spectrum monitoring equipment which can receive and determine some 
information from the received signal then it would be “radio equipment” under 
RED

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Tel: +44 (0)7946 624317

Web: https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 

From: Ralph McDiarmid mailto:rmm.priv...@gmail.com> > 
Sent: Thursday, October 5, 2023 12:23 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] SV: [PSES] Radio receivers under RED? Yes

 

Given the reasoning you propose, your spectrum analyser, as an unintentional 
radiator, should be out of scope of the RED.  If it were, then all television 
and radio receivers would also fall under the RED.

 

 

From: Amund Westin mailto:am...@westin-emission.no> 
> 
Sent: Wednesday, October 4, 2023 10:51 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] SV: [PSES] Radio receivers under RED? Yes

 

Hi Charlie

 

I was made aware that in the RED Guide, there is something about equipment that 
does not fall under the RED.

 

 

1.6.3.3 Products that use electromagnetic waves exclusively for other purposes 
than radio communication and/or radiodetermination 

Products and applications that use electromagnetic waves exclusively for other 
purposes than radio communication and/or radiodetermination (products that 
propagate electromagnetic waves in space, but this propagation is not intended 
and not used for the purpose of radio communication or radiodetermination.) are 
not covered by the RED, for example: 

 inductive warming and heating appliances; 

 pure wireless power transfer (without any communication or 
radiodetermination); 

 high frequency surgical equipment and systems; 

 cookware suitable for inductive heating appliances; 

 test equipment if intended to use radio waves, exclusively, for testing other 
devices (18)  Footnote 18: Needs to be assessed on a case-by-case basis, in 
order to determine if a specific type of test equipment is covered (or not 
covered) by the RED.  

 

 

The product in this case is a receiver-only product (with an external antenna 
connected) and its main purpose is to analyze a received signal from another 
radio (VHF/UHF) product. So, it is a professional test / analyze radio receiver 
equipment.

 

It can be compared to a portable spectrum analyzer with an external dipole 
antenna connected.

 

 

With this additional information, do you think we are still within RED or are 
we now outside RED? ….. 

 

 

Best regards Amund

 

 

 

 

 

Fra: Charlie Blackham 
Sendt: 5. september 2023 09:35
Til: Amund Westin mailto:am...@westin-emission.no> 
>; EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Emne: RE: [PSES] Radio receivers under RED? Yes

 

Amund

 

Yes, receivers are within scope of RED as they meet the definition of “radio 
equipment” in article 2:

 

‘radio equipment’ means an electrical or electronic product, which 
intentionally emits and/or receives radio waves for the purpose of radio 
communication and/or radiodetermination, or an electrical or electronic product 
which must be completed with an accessory, such as antenna, so as to 
intentionally emit and/or receive radio waves for the purpose of radio 
communication and/or radiodetermination;

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Tel: +44 (0)7946 624317

Web: https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 

From: Amund Westin mailto:am...@westin-emission.no> 
> 
Sent: Tuesday, September 5, 2023 7:17 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] Radio receivers under RED? Yes

 

I think we have discussed this topic previous, but I can’t find the email tread.

But I assume it is the fact the equipment that even only receive, will anyway 
be included under RED. In this case, it’s a radio receiver measurement device 
with whip antenna mounted and that receives in the VHF/UHF range.

 

>From RED text, page 2:

(11) Although receivers do not themselves cause harmful interference, reception 
capabilities are an increasingly important factor in ensuring the efficient use 
of radio spectrum by way of an increased resilience of receivers against 
harmful interference

Re: [PSES] SV: [PSES] Radio receivers under RED? Yes

[Ralph McDiarmid]

Given the reasoning you propose, your spectrum analyser, as an unintentional 
radiator, should be out of scope of the RED.  If it were, then all television 
and radio receivers would also fall under the RED.

 

 

From: Amund Westin  
Sent: Wednesday, October 4, 2023 10:51 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] SV: [PSES] Radio receivers under RED? Yes

 

Hi Charlie

 

I was made aware that in the RED Guide, there is something about equipment that 
does not fall under the RED.

 

 

1.6.3.3 Products that use electromagnetic waves exclusively for other purposes 
than radio communication and/or radiodetermination 

Products and applications that use electromagnetic waves exclusively for other 
purposes than radio communication and/or radiodetermination (products that 
propagate electromagnetic waves in space, but this propagation is not intended 
and not used for the purpose of radio communication or radiodetermination.) are 
not covered by the RED, for example: 

 inductive warming and heating appliances; 

 pure wireless power transfer (without any communication or 
radiodetermination); 

 high frequency surgical equipment and systems; 

 cookware suitable for inductive heating appliances; 

 test equipment if intended to use radio waves, exclusively, for testing other 
devices (18)  Footnote 18: Needs to be assessed on a case-by-case basis, in 
order to determine if a specific type of test equipment is covered (or not 
covered) by the RED.  

 

 

The product in this case is a receiver-only product (with an external antenna 
connected) and its main purpose is to analyze a received signal from another 
radio (VHF/UHF) product. So, it is a professional test / analyze radio receiver 
equipment.

 

It can be compared to a portable spectrum analyzer with an external dipole 
antenna connected.

 

 

With this additional information, do you think we are still within RED or are 
we now outside RED? ….. 

 

 

Best regards Amund

 

 

 

 

 

Fra: Charlie Blackham 
Sendt: 5. september 2023 09:35
Til: Amund Westin mailto:am...@westin-emission.no> 
>; EMC-PSTC@LISTSERV.IEEE.ORG  
Emne: RE: [PSES] Radio receivers under RED? Yes

 

Amund

 

Yes, receivers are within scope of RED as they meet the definition of “radio 
equipment” in article 2:

 

‘radio equipment’ means an electrical or electronic product, which 
intentionally emits and/or receives radio waves for the purpose of radio 
communication and/or radiodetermination, or an electrical or electronic product 
which must be completed with an accessory, such as antenna, so as to 
intentionally emit and/or receive radio waves for the purpose of radio 
communication and/or radiodetermination;

 

Best regards

Charlie

 

Charlie Blackham

Sulis Consultants Ltd

Tel: +44 (0)7946 624317

Web: https://sulisconsultants.com/ 

Registered in England and Wales, number 05466247

 

From: Amund Westin mailto:am...@westin-emission.no> 
> 
Sent: Tuesday, September 5, 2023 7:17 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] Radio receivers under RED? Yes

 

I think we have discussed this topic previous, but I can’t find the email tread.

But I assume it is the fact the equipment that even only receive, will anyway 
be included under RED. In this case, it’s a radio receiver measurement device 
with whip antenna mounted and that receives in the VHF/UHF range.

 

>From RED text, page 2:

(11) Although receivers do not themselves cause harmful interference, reception 
capabilities are an increasingly important factor in ensuring the efficient use 
of radio spectrum by way of an increased resilience of receivers against 
harmful interference and unwanted signals on the basis of the relevant 
essential requirements of Union harmonisation legislation.

 

Thanks!

BR

Amund

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This message is from the IEEE 

[PSES] seeing postings

[Ralph McDiarmid]

I see that I had to set something up on the list server so that I can see my
own postings.

 


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Re: [PSES] EMI filtering for 600V AC mains system

[Ralph McDiarmid]

Circuit simulation (Pspice or similar) would allow you to find highest
working voltage on each capacitor under normal and under single-fault
conditions including component tolerances and line voltage variation.  In
this country, a nominal 347/600V service has voltage variation limits of
550V to 625V measured phase-to-phase.   X2 type capacitors rated 400Vac
should be suitable in your applications, but you need to do the analysis and
maybe do a few tests.

Ralph 

From: Boštjan Glavič  
Sent: Wednesday, September 27, 2023 8:01 AM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] EMI filtering for 600V AC mains system

Dear safety experts

I hope there is someone who can help me on below topic.


Customer is designing 600V rectifier for datacentres. Mains voltage in
datacentre will be 600Vac, delta system (no neutral), OVCII with 4000V
transients. Product will be certified according IEC 62368-1.

They are designing input EMI filter with X caps. They plan to use so call Y
filter (with artificial neutral point not being connected). Question is what
kind of X caps they need to use and what kind of rating.

Question is raised since clause 5.5.2 is not so clear in below paragraph (do
we need to apply in this case or not)

Under single fault conditions, if a capacitor or RC unit consists of more
than one capacitor, the voltage on each of the remaining individual
capacitors shall not exceed the voltage rating of the relevant individual
capacitors. 


If customer is using X1 capacitor rated min. 350V on the positions CX1-CX3
is such configuration acceptable or not? If not, why not.





Thank you for your support.

Best regards,
Bostjan
SIQ Ljubljana

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[PSES] test message only

[Ralph McDiarmid]

 


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Re: [PSES] Reliability/Fault analysis tools?

[Ralph McDiarmid]

Brian, 

As a good starting point, I recommend reading the following:

UL991 :  Safety-Related Controls Employing Solid-State Devices

CSA C22.2 No. 0.8 : Safety Functions Incorporating Electronic Technology

There is functional safety analysis software available, but some may have a
hefty price tag.

Ralph

From: Brian Gregory  
Sent: Thursday, September 21, 2023 3:38 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Reliability/Fault analysis tools?

 
 EV Chargers getting more and more complicated
 
For our controls investigations, hardware failures need to be assessed.  One
of the safety standards calls out MIL-STD-217, which has got to be nearly as
old as my Dad.   Looking for more up to date, modern and computer-based
processes and procedures.
 
thanks all!
 
Colorado Brian 

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Re: [PSES] 50Hz Product and the EMC Directive

[Ralph McDiarmid]

The phrase, “as to ensure that”, implies some testing would be needed for both 
emissions and immunity.  The directive doesn’t insist on testing, but to meet 
the “essential requirements” testing would seem the only way to reinforce a 
claim of compliance. 

Ralph McDiarmid
(Vancouver)

From: mailto:bart.de.gee...@telenet.be <mailto:bart.de.gee...@telenet.be> 
Sent: Wednesday, September 27, 2023 7:00 AM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] 50Hz Product and the EMC Directive

Hi Scott,

The directive also states:

ANNEX I
ESSENTIAL REQUIREMENTS
1.   General requirements
Equipment shall be so designed and manufactured, having regard to the state of 
the art, as to ensure that:
(a)
the electromagnetic disturbance generated does not exceed the level above which 
radio and telecommunications equipment or other equipment cannot operate as 
intended;

(b)
it has a level of immunity to the electromagnetic disturbance to be expected in 
its intended use which allows it to operate without unacceptable degradation of 
its intended use.


⇨ Besides the ‘emission’ part of the test there is also the ‘immunity’ related 
aspect of it.  (You can do electrostatic discharge, EFT, surge and other 
tests).   (and I do not see a reason why products not containing active 
oscillators would be excluded from immunity testing). 
⇨ Although your product might not contain an active oscillator, I have seen 
products that only contained a few passive components, but where the 
manufacturer still succeeded to make an active oscillator (unwantedly) that 
exceeded the legal limits by more than 30 dB.  



Greetings,
Bart

From: Scott Douglas <mailto:sdouglas...@gmail.com> 
Sent: woensdag 27 september 2023 15:35
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] 50Hz Product and the EMC Directive

Hello List Experts,

We have a product that operates at line frequency (50 or 60 Hz). It is a power 
conditioner which includes filtering, surge suppression, and extreme voltage 
shut down. It is purely analog and contains nothing more complex than 
transistors.

We believe the EU EMC Directive does not apply to the product because it does 
not operate any higher than 60 Hz and cannot generate EMI whether radiated or 
conducted. 

>From EU Directive 2014/30/EU, Article 2 (2 (d)):

2. This Directive shall not apply to:
(d) equipment the inherent nature of the physical characteristics of which is 
such that:
(i) it is incapable of generating or contributing to electromagnetic emissions 
which exceed a level allowing radio and telecommunication equipment and other 
equipment to operate as intended; and
(ii) it operates without unacceptable degradation in the presence of the 
electromagnetic disturbance normally consequent upon its intended use;
I am not aware of any EMI standards that cover this type of product, most 
conducted EMI starts at 9kHz or 150 kHz, and radiated EMI typically starts at 
30 MHz. 

There is an inspector in an EU country that believes the EMC Directive does 
apply. Their letter makes these statements:

The EU Declaration of Conformity (DoC) is incorrect or incomplete (Article 15; 
Annex IV; etc. of EU Directive 2014/30/EU).

A conformity assessment procedure seems to be incomplete (Article 14) to 
demonstrate that the apparatus meets the essential requirements set out in 
Article 6 and Annex I of EU Directive 2014/30/EU. EU Directive 2014/30/EU is 
missing.

Our DofC does not list the EMC Directive, specifically because we think it does 
not apply. It also does not list any EMI/EMC standards as we find none that 
apply.
Is there a Harmonized Standard that would cover this type of product for the 
EMC Directive?
Is it normal to list a directive in a DofC if that directive does not apply? 
How does one convince the inspector that the directive does not apply?
 Looking forward to any and all comments.
Scott

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Re: [PSES] 50Hz Product and the EMC Directive

[Ralph McDiarmid]

The phrase, “as to ensure that”, implies some testing would be needed for both 
emissions and immunity.  The directive doesn’t insist on testing, but in order 
to meet the “essential requirements” testing would seem the only way to 
reinforce a claim of compliance. 

 

From: bart.de.gee...@telenet.be  
Sent: Wednesday, September 27, 2023 7:00 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] 50Hz Product and the EMC Directive

 

Hi Scott,

 

The directive also states:

 

ANNEX I

ESSENTIAL REQUIREMENTS

1.   General requirements

Equipment shall be so designed and manufactured, having regard to the state of 
the art, as to ensure that:


(a)

the electromagnetic disturbance generated does not exceed the level above which 
radio and telecommunications equipment or other equipment cannot operate as 
intended;

 


(b)

it has a level of immunity to the electromagnetic disturbance to be expected in 
its intended use which allows it to operate without unacceptable degradation of 
its intended use.

 

 

*   Besides the ‘emission’ part of the test there is also the ‘immunity’ 
related aspect of it.  (You can do electrostatic discharge, EFT, surge and 
other tests).   (and I do not see a reason why products not containing active 
oscillators would be excluded from immunity testing). 
*   Although your product might not contain an active oscillator, I have 
seen products that only contained a few passive components, but where the 
manufacturer still succeeded to make an active oscillator (unwantedly) that 
exceeded the legal limits by more than 30 dB.  

 

 

 

Greetings,

Bart

 

From: Scott Douglas mailto:sdouglas...@gmail.com> > 
Sent: woensdag 27 september 2023 15:35
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] 50Hz Product and the EMC Directive

 

Hello List Experts,

We have a product that operates at line frequency (50 or 60 Hz). It is a power 
conditioner which includes filtering, surge suppression, and extreme voltage 
shut down. It is purely analog and contains nothing more complex than 
transistors.

We believe the EU EMC Directive does not apply to the product because it does 
not operate any higher than 60 Hz and cannot generate EMI whether radiated or 
conducted. 

>From EU Directive 2014/30/EU, Article 2 (2 (d)):

 

2. This Directive shall not apply to:



(d) equipment the inherent nature of the physical characteristics of which is 
such that:



(i) it is incapable of generating or contributing to electromagnetic emissions 
which exceed a level allowing radio and telecommunication equipment and other 
equipment to operate as intended; and
(ii) it operates without unacceptable degradation in the presence of the 
electromagnetic disturbance normally consequent upon its intended use;



I am not aware of any EMI standards that cover this type of product, most 
conducted EMI starts at 9kHz or 150 kHz, and radiated EMI typically starts at 
30 MHz. 

There is an inspector in an EU country that believes the EMC Directive does 
apply. Their letter makes these statements:

The EU Declaration of Conformity (DoC) is incorrect or incomplete (Article 15; 
Annex IV; etc. of EU Directive 2014/30/EU).

A conformity assessment procedure seems to be incomplete (Article 14) to 
demonstrate that the apparatus meets the essential requirements set out in 
Article 6 and Annex I of EU Directive 2014/30/EU. EU Directive 2014/30/EU is 
missing.


Our DofC does not list the EMC Directive, specifically because we think it does 
not apply. It also does not list any EMI/EMC standards as we find none that 
apply.

Is there a Harmonized Standard that would cover this type of product for the 
EMC Directive?

Is it normal to list a directive in a DofC if that directive does not apply? 

How does one convince the inspector that the directive does not apply?

 Looking forward to any and all comments.

Scott

  _  

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 &A=1

[PSES] audio amplifier tests - UL 1711

[Ralph McDiarmid]

Anyone know the technical justification for the percent THD limit
calculation in clause 35.2 in UL1711 ?

Without HTML, the plain text reads:

 THD (%) = 20 x e^(-0.000189(f-2800))  where f is the bandwidth in
Hz.

Seems a strange way to specify THD as a function of audio amplifier
bandwidth.

Thoughts ?

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Re: [PSES] DFMEA Component Selection

[Ralph McDiarmid]

I would only add that those details need to be consider during design, not 
after the design.  

 

 

Ralph

 

 

From: Douglas Nix <0bb8ff993b10-dmarc-requ...@listserv.ieee.org> 
Sent: Wednesday, August 30, 2023 6:31 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] DFMEA Component Selection

 

Hi Mike,

 

I agree completely. These are the details that, after the design, can make or 
break a product..

 

--

Doug Nix

d...@mac.com  

 

When you put a thing in order, and give it a name, and you are all in accord, 
it becomes.

 

>From the Navajo, Masked Gods, Waters, 1950 

 





On Aug 29, 2023, at 17:18, MIKE SHERMAN mailto:msherma...@comcast.net> > wrote:

 

Doug speaks from experience similar to mine---the standards tend to do a good 
job of addressing risks, so it's good to spend some time on things maybe not 
explicitly covered in the standards. 

  

My pet peeve list includes workmanship issues, such as properly torquing all 
terminal connections, especially those on components. Plus routing, bundling, 
and securing the wiring correctly (e.g., properly segregating low voltage 
wiring). And only stripping the specified length on line voltage conductors 
where they enter components, to reduce the risk of touch shock. These are the 
kind of details a good UL 508A panel shop will do for you if you contract it 
out. Conversely, these are things you have to come up to speed on if you do the 
work in house. 

  

Another thought: not only is the designer a good person to have in on the 
analysis, but also bring in a field service technician for a reality check on 
how things are actually used (I love Doug's photograph!). 

  

Mike Sherman 

Sherman PSC LLC 

On 08/29/2023 4:01 PM CDT John Allen mailto:jral...@productsafetyinc.com> > wrote: 

  

  

Very good point on the Designer to be a part of it.  You may consider a HARA vs 
an FMEA to get to the bottom of your question.  To Rich Nute’s point a long 
time ago to me – what are the hazards we are concerned about??

 

A Hazard Analysis Risk Assessment is a top down approach of Hazards vs an FMEA 
calling out each part and what can go wrong.  HARA asks what are all the 
Hazards associated with this product/system/event.  What in the design 
mitigates against those hazards?  What tests can I do to prove those mitigating 
factors work? and is that adequate?

 

There are many ways to understand overall safety of a product/system/event – 
FMEA, HARA, HAZOP, etc.  We should work to a common way or even some guidance 
in this area.  The LVD says a “risk assessment shall be in the technical 
documentation”.  Thanks for the guidance!!

 

If there are any leaders in this group regarding such I’d love to discuss 
possible Hazard Analysis and Risk Assessment methodologies and Standard(s).  
Along with a PSES Technical Committee and Track at ISPCE.

 

Best Regards and Be Safe,

 

John

 

John Allen | President & CEO | Product Safety Consulting, Inc.

Your Outsourced Compliance Department®

630-238-0188, Cell: 630-330-3145

 
 
   
  
https://www.youtube.com/channel/UCVSzENmSoWeNFSBQcOYN7-A
  www.productsafetyinc.com

 

IEEE Product Safety Engineering Society

President Elect 2023, President 2024-2025, Past President 2026

President 2016-2019

Compliance 101 Technical Committee Chairman

IEEE Senior Member

 



Keeping our members informed and educated on Product Safety and Compliance

 

  
https://ewh.ieee.org/soc/pses/index.html

 

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From: Douglas Powell mailto:doug...@gmail.com> > 
Sent: Tuesday, August 29, 2023 3:12 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] DFMEA Component Selection

 

[EXTERNAL EMAIL] DO NOT CLICK links or attachments unless you recognize the 
sender and know the content is safe.

I

Re: [PSES] thoughts on ESD test lab problems

[Ralph McDiarmid]

I wonder why industry is spending so much on EMC compliance.  Is it because the 
development teams are leaving this work to the final phase of the design, where 
changes are expensive and schedules slip ?  

 

Ralph 

 

From: doug emcesd.com  
Sent: Saturday, August 12, 2023 8:57 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] thoughts on ESD test lab problems

 

Thanks everyone for your thoughts. But in the case of ESD testing, IEC 
61000-4-2 is not a very good standard. We knew this in 1996 where work done by 
myself and others showed  that the waveform needs to have a di/dt spec to rule 
out the uncontrolled high frequency ringing many simulators generate that bear 
no connection to reality. This should be a reasonable simple design to do as 
one simulator already has no high frequency ringing on its current waveform.

 

In addition, we now know these same simulators have uncontrolled radiation as 
well that does not reflect what equipment is subjected to in the field.

 

All the work on the waveform was done about 30 years ago and should be in the 
IEC records.

 

All this causes companies to spend hundreds of millions of dollars (my estimate 
from familiarity with my client’s designs) per year in delayed product 
introductions, and to a small extent engineering costs. The costs to redesign 
simulators would be a tiny fraction of what the current costs to industry are 
in only one year.

 

Doug Smith

Sent from my iPhone

IPhone: 408-858-4528

Office: 702-570-6108

Email: d...@dsmith.org  

Website: http://dsmith.org

  _  

From: Brent DeWitt mailto:bdew...@ix.netcom.com> >
Sent: Saturday, August 12, 2023 5:05:40 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG   
mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >
Subject: Re: [PSES] thoughts on ESD test lab problems 

 

I suspect that folks who have been directly involved with air-discharge ESD can 
appreciate it's inherent, operator influenced, uncertainly.

Having run both internal and third party EMC test labs, I recognize that few 
things are done "perfectly" (whatever "perfect" is), but I've always considered 
it my responsibility to catch the errors and correct them before they influence 
my customers outcome.

The larger the lab, the more likely it is that the experience of the tester 
will vary.  I am not saying that the customer show bear the brunt of that, the 
lab should have test review processes in place to mitigate it.

Had to pitch in.

Brent DeWitt

On 8/12/2023 1:47 PM, John Mcbain wrote:

The basic question is, "How good is good enough?" 

Risk standards for product safety address that question to some extent, but it 
applies to every lab measurement, whether the applicable standards (or 
regulations) consider it or not.




Best regards, 

John McBain

 

 

On Sat, Aug 12, 2023 at 2:26 AM John Woodgate mailto:j...@woodjohn.uk> > wrote:

But crossing t's and dotting i's is exactly what is required by competence 
standards, including the several ISO 170XX series. Furthermore, standards 
specify performance of test equipment, if possible, and only if that is not 
possible, they specify design. If that is not possible, they specify 
construction, and indeed many CISPR and other standards specify test set-ups 
with elaborate drawings.

EMC testing is DIFFICULT. It does involve extensive experience and it is 
costly. Management systems are/should be in place to catch errors. Daily and 
weekly verifications are required. In many cases, running tests on a known 
sample are OK, but that's dodgy for ESD, because repeated testing WILL cause 
damage.

On 2023-08-12 03:25, Ken Javor wrote:

No way am I jumping in the middle of this debate, but it is extremely useful in 
another way.

 

A few observations:

 

ESD is by its very nature a chaotic event (air discharge more so than contact).

 

It is not entirely surprising that someone who has spent decades working on 
something would find examples of non-idealities in the work of technicians 
doing rote work following canned test procedures.  A test facility isn’t going 
to make a profit employing a septuagenarian devoted to crossing every “t” and 
dotting every “i.”  (Written by someone pushing that age bracket pretty hard).

 

IFF (if and only if) Mr. Smith’s observations are correct, that is an 
indictment of the test requirement/method. That is, it is the responsibility of 
the standards committees to write these such that they can be adequately 
performed by the average test facility and personnel. If it takes someone with 
five decades of experience, and they must spend an inordinate amount of time 
($$$) to get it right, then the standard is a failure. 

 

-- 

Ken Javor

(256) 650-5261

 

From: "doug emcesd.com 

Re: [PSES] Friday Question - Line Cords in China

[Ralph McDiarmid]

Manufacturers cannot side-step liability by claiming ignorance.  The 
manufacture is solely responsible for any product they place on the market, 
with or without the correct power cord.

 

From: Douglas Powell  
Sent: Friday, August 11, 2023 7:53 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Friday Question - Line Cords in China

 

I believe you are correct.  

 

Simply shipping the wrong cord types to certain locations is actually 
prohibited, and in general, including incorrect types could be viewed as 
endorsement of their use in other areas. A thing that should be simple, now 
gets complicated.

 

On occasion, I've heard manufacturers say things like "I've heard of this but 
have no official knowledge that it's true", as a way to side step liability. 
I'm not certain this is considered a valid argument, should someone be injured.

 

While it's convenient and sometimes cost effective to make shipping kits more 
generic, I usually recommend including in BOMs some indicator of the ISO 
Alpha-2 or ISO Alpha-3 country code and make kits so the correct materials are 
included for the location involved.

 

I find that, although seemingly simple, it's very easy to get tripped up over 
such matters. I've also had difficulty in the past with multi-language 
labeling, i.e. combined language labels. In certain countries people become 
offended if the wrong language is on products along side their own language. In 
this case I'm thinking of a 4-language label I once used.

Best regards, Doug

Douglas E Powell
Laporte, Colorado USA

 

On Fri, Aug 11, 2023, 8:27 AM Chas Grasso mailto:charles.gra...@dish.com> > wrote:

Hello Doug - Wow I had no idea that this issue existed. Thanks for bringing it 
up! 
As I understand that the inclusion of incorrect cords in a package spreads the 
incorrect
conclusion that ALL of the cords are suitable for use. Did I get that right?

 

 

On Fri, Aug 11, 2023 at 8:00 AM Douglas Powell mailto:doug...@gmail.com> > wrote:

 This message originated outside of DISH and was sent by: doug...@gmail.com 
  

 


  _  


All,

 

I was talking with a client recently about shipping line cords to various 
countries around the world and how some do not allow the incorrect cords within 
a shipment while others do. Brazil, as far as I know, does not permit incorrect 
cordage. Argentina, Australia, and China (PRC) are all mutually exclusive. 
South Africa and India are mutually exclusive. Japan, Taiwan, and the United 
States are all mutually exclusive. If not prohibited, it is frequently cheaper 
to include multiple cords rather than create multiple regional SKUs when 
products are in low-volume production.

 

That said, apparently the China market often likes to use US-style receptacles 
(types A or B), even though they use 220 V (😬). The US-style plug has better 
density (twice as many receptacles in the same space as the China receptacle 
(Type C, or I ?), and with the US receptacles, there are many more aftermarket 
cable options available.  So I suppose that's my question: "Is this usage 
typical in China?"

 

Of course, the big issue is that the US plug is not rated for the higher 
voltages, even though historically some people may say it works.  I even fouind 
a website that shows this, 
https://www.travelchinaguide.com/essential/electricity.htm

 

I believe it is critical for manufacturers to not condone the use of the US 
plug in this manner, which appears to be common practice. And I usually advise 
that this type of usage should never be described, recommended, or mentioned in 
any manuals, brochures, or other written material produced by a company, either 
externally or internally. If anyone is injured and an investigation reveals 
agreement with this usage, the company may be held liable.

 

Thoughts??

 

-Doug

 

 

Douglas E Powell

Laporte, Colorado, USA

  doug...@gmail.com

  LinkedIn

 

(UTC-06:00, US-MDT)

 

 


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Re: [PSES] Friday Question - Line Cords in China

[Ralph McDiarmid]

How would the customs folks in those countries check appliance line cords ?   
Do they open boxes, pull contents, and inspect?

 

If the USA plug is not rated for higher voltage, does it really present a 
hazard ?  (compliance vs safety)  The USA/Canadian plugs have a LOTS of 
creepage distance between conductors.

 

From: Douglas Powell  
Sent: Friday, August 11, 2023 7:00 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Friday Question - Line Cords in China

 

All,

 

I was talking with a client recently about shipping line cords to various 
countries around the world and how some do not allow the incorrect cords within 
a shipment while others do. Brazil, as far as I know, does not permit incorrect 
cordage. Argentina, Australia, and China (PRC) are all mutually exclusive. 
South Africa and India are mutually exclusive. Japan, Taiwan, and the United 
States are all mutually exclusive. If not prohibited, it is frequently cheaper 
to include multiple cords rather than create multiple regional SKUs when 
products are in low-volume production.

 

That said, apparently the China market often likes to use US-style receptacles 
(types A or B), even though they use 220 V (😬). The US-style plug has better 
density (twice as many receptacles in the same space as the China receptacle 
(Type C, or I ?), and with the US receptacles, there are many more aftermarket 
cable options available.  So I suppose that's my question: "Is this usage 
typical in China?"

 

Of course, the big issue is that the US plug is not rated for the higher 
voltages, even though historically some people may say it works.  I even fouind 
a website that shows this, 
https://www.travelchinaguide.com/essential/electricity.htm

 

I believe it is critical for manufacturers to not condone the use of the US 
plug in this manner, which appears to be common practice. And I usually advise 
that this type of usage should never be described, recommended, or mentioned in 
any manuals, brochures, or other written material produced by a company, either 
externally or internally. If anyone is injured and an investigation reveals 
agreement with this usage, the company may be held liable.

 

Thoughts??

 

-Doug

 

 

Douglas E Powell

Laporte, Colorado, USA

  doug...@gmail.com

  LinkedIn

 

(UTC-06:00, US-MDT)

 

 

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Re: [PSES] Necessary Lab accreditations, class 2 permissible change

[Ralph McDiarmid]

Cord-connected equipment?

 

From: Elliott Martinson  
Sent: Thursday, August 10, 2023 12:27 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Necessary Lab accreditations, class 2 permissible change

 

If it were to become a leakage current issue, I’d wonder whether the
parasitic inductance [i.e., enclosed loop area] in the current paths through
the Y-Caps could be reduced, as that can often be much more meaningful than
the actual capacitance value. If package choice and layout were already
optimal, one might still be able to parallel 2x the # of caps but cut their
capacitance values in ½  in order to increase the EMC margin without
affecting leakage/touch current?

 

Elliott

 

From: Chester Summers mailto:chester.summ...@ditchwitch.com> > 
Sent: Thursday, August 10, 2023 11:22 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] Necessary Lab accreditations, class 2 permissible change

 

Hi, Brian—

 

More margin is good but be sure to check that your leakage/touch current is
still acceptable.  Sometimes striking that balance means living with a
little less emissions margin than an EMC guy would prefer. :)

 

Good luck,

Chet Summers

 

From: Brian Gregory mailto:brian_greg...@netzero.net> > 
Sent: Thursday, August 10, 2023 10:01 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] Necessary Lab accreditations, class 2 permissible change

 

Think Before You Click: This email originated outside our organization. 

 

Yes, we increased the Y-Caps to get more margin.  And we did!

So, to qualify for a Class 1 permissive change, we'd need to show before &
after data ?

 

Applying for a Class 2 permissive change, means FCC will look only at the
latest data to be sure it passes?

 

Colorado Brian

-- Original Message --
From: John Woodgate mailto:j...@woodjohn.uk> >
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] Necessary Lab accreditations, class 2 permissible change
Date: Thu, 10 Aug 2023 00:02:42 +0100

What are you changing about the Y-caps? If it's just a new supplier and the
caps conform to the required component standard, there is no degradation.
Reducing he capacitance would be a degradation for EMC but not for safety. 

Who determines the class is the person who has all the necessary data. The
test house of surveillance authority check the decision.

On 2023-08-09 23:20, Brian Gregory wrote:

 

 Hello EMC experts,

 

A question came up today about filing new results to FCC for our legacy
product.

 

1.  If the filing is only for FCC, then the lab providing the report does
not need A2LA accreditation,

2.  If the filing is for a safety report, then the lab does need A2LA
accreditation.

 

Have I got that right?

 

We're filing some small board changes, including Y-caps and can't figure out
if this is a Class 2 permissible change, defined as:  " includes those
modifications which degrade the performance characteristics as reported to
the Commission"

 

3.  How or who determines if our change is Class 2 (degraded performance) or
Class 1? 

We think the results are better, but it's not like we got uniformly more
margin across the board.   

 

Thanks!

 

Colorado Brian

720-450-4933


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Re: [PSES] BBC news article re Li-ion batteries...

[Ralph McDiarmid]

UL1973 and UL1642 do a pretty through job of addressing functional safety of 
batteries and safety of the individual cells.  Perhaps some LiON batteries are 
finding their way into the USA market without 3rd party certification.  How to 
prevent uncertified or unlisted products from reaching the retailers ?

 

From: Scott Xe  
Sent: Saturday, August 5, 2023 9:02 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] BBC news article re Li-ion batteries...

 

Dear Ted,

 

I couldn't agree with your views more.  It is crucial for us to tackle these 
issues, despite the existing regulations and testing standards in place.  The 
regulatory authorities and enforcement bodies must thoroughly assess why these 
measures have proven ineffective in preventing the sale of unsafe products in 
the market.

 

Regards,

 

Scott

 

 

On Fri, 28 Jul 2023 at 20:39, Ted Eckert 
<07cf6ebeab9d-dmarc-requ...@listserv.ieee.org 
 > wrote:

I can give additional background on the reason why these fires have become 
common in New York. A large number of residents of New York City use delivery 
services for goods and food, such as Uber-Eats, DoorDash, and GrubHub. The 
adoption of these delivery services accelerated during the COVID lockdown, and 
it has become a major business in the city. The drivers for these services are 
contractors, not employees, and they get paid based on delivery without 
reimbursement for expenses. Driving a car is expensive, and finding parking is 
very hard. Delivery people who drive cars often lose money because they incur 
too many parking tickets. The delivery people have switched to battery-powered 
electric scooters and bicycles. 

 

These small electric vehicles are optimal for the delivery services since they 
can move around stopped traffic easily, and they can be brought inside the door 
of a building for a delivery, avoiding the risk of parking fines or the vehicle 
getting stolen. However, the batteries will only last for a few hours of use at 
most. The delivery people want the option of using the electric bicycle or 
scooter all day to try to make more money. The common solution is to remove the 
battery that came with the vehicle and replace it with a much larger 
after-market replacement. The delivery services do not pay well, so people look 
for the cheapest option they can find for a large battery. The regulations in 
the United States make it easy to order something online that has undergone no 
safety testing at all. The result is that a battery of dubious quality is 
placed in an electric bicycle by a person with dubious technical skills. No 
effort may have been made to match the charger with the battery. The battery 
may not be provided with the physical protection necessary to avoid damage 
during use. The question isn’t why there are so many fires, but why there 
aren’t more considering the circumstances. 

 

In the United States, there is reasonable indemnification of the test 
laboratories. The test laboratories accredited under the OSHA Nationally 
Recognized Test Laboratory (NRTL) system have a reasonable level of protection. 
If a product carrying one of their certification marks fails, they can be sued, 
but it would be hard for that law suit to make it to court. The test 
laboratories will indicate that they tested samples on a given date and found 
those samples to meet the technical requirements of the standard at that time. 
Their report does not state that the samples were safe. It only states that 
they passed testing of specific requirements. The legal system places the 
responsibility for safety onto the manufacturer.

 

The challenges that I see are that battery manufacturers willing to ignore 
safety might be willing to forge safety certification marks and documents. I 
strongly suspect you can buy product online and have them shipped to the UK or 
Europe with a Declaration of Conformity based on nothing. I suspect 
manufacturers will claim their products meet requirements without testing or 
documentation to back it up. If the manufacturer is located outside of Europe 
and has no legal presence there, they can sell on line and avoid 
responsibility. I strongly suspect that this is why there are stricter 
requirements for online importers and distributors in the new GPSR. 

 

The overall issue is not new. Insufficient testing, forged or missing 
documentation, irresponsible actors shipping from the far side of the world and 
the other problems have existed for a while. However, the large size of the 
batteries in these scooters and bicycles, and the common charging of them 
indoors in buildings with a large number of residents, creates an issue where a 
failure can jeopardize many more lives in a single incident.

 

 

Ted Eckert

 

The opinions expressed are my own and do not necessarily reflect those of my 
employer.

 

From: Matthew Wilson | GBE mailto:matthew.wil...@gbelectronics.com> > 

Re: [PSES] Hazard warning labels on panel doors where COTS UPS installed?

[Ralph McDiarmid]

Doug, a quick search through NFPA70 (USA national electrical code) says in
article 645 Information Technology Equipment:

645.16 Marking. Each unit of an information technology system supplied by a
branch circuit shall be provided with a
 manufacturer's nameplate, which shall also include the input power
requirements for voltage, frequency, and maximum 
rated load in amperes.

I endorse John Woodgate's answer;  if in doubt, label it.   

I'm delighted to see a few familiar names after my long hiatus from this
forum.   I'm now semi-retired from the industry.

Ralph

From: Doug Nix  
Sent: Wednesday, August 2, 2023 2:24 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Hazard warning labels on panel doors where COTS UPS
installed?

Colleagues,

I have a client who has installed a COTS UPS in an industrial control panel.
The UPS is being used to keep the HMI alive in a power outage or if the
disconnecting device is switched off.

I have scoured the resources that I have, and I can find nothing that
requires a label on the outside of the panel to indicate that there is a UPS
inside. EN 60204-1:2018 does not address this. I have a copy of EN IEC
62040-1, and it does not require a hazard warning label anywhere.

Any guidance you might offer is appreciated.

Doug Nix
mailto:d...@ieee.org
+1 (519) 729-5704


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Re: [PSES] GFCI vs GFPE discussion

[Ralph McDiarmid]

“current limit of 30mA protects 95 % of the population”

They didn’t want to try for 100%  ? I'm no expert and I don't know if we 
have one on this forum for this complex topic, but  ask how can one limit be 5X 
the other and still afford the same level of protection?  Perhaps not intended 
to, as in shock versus electrocution protection. 

Is 6mA enough for strong muscle reaction or a startle reaction sufficient to 
cause someone to loose balance for instance?

Still, some protection better than none at all. 

Ralph McDiarmid
Product Compliance Specialist
Solar Business
Schneider Electric


From: Pete Perkins [mailto:0061f3f32d0c-dmarc-requ...@ieee.org] 
Sent: Tuesday, January 30, 2018 10:06 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] GFCI vs GFPE discussion

Brian, et al
   
   Low current protection devices are intended to protect people.  

   The long term letgo-immobilization current of 5mA covers the 
full population and opens any circuit which exceeds this level (ok, the UL 
limit for GFCIs is 4mA  to 6 mA),  But you get the idea.  

   The long term Ventricular Fibrillation current limit of 30mA 
protects 95 % of the population on the face of the earth.  The Euro systems use 
of RCDs require this protection in many installations (but I’m not familiar 
with the installation code details).  

   Here in the US we are developing protection devices that will 
work at 15 mA and 25 mA.  These are intended for use with charging electric 
vehicles.  The 15 mA device will be used in residential installations and the 
25 mA device will be used in commercial installations (haven’t followed the 
code development but believe that this is how it is going).  
 
   All  of these devices have been designed for sinusoidal AC 
systems and they all have false tripping issues when used with equipment with 
line switching.  SMPS and VSD units are a problem today in that they trip a 
small number of protection devices; their use is spreading into many more types 
of products.  From my perspective the units each have a statistical range of 
protection  or operation and they seem to overlap a small percentage of the 
time; this gives rise to ‘nuisance tripping’ (meaning undiagnosed tripping).  
This is an issue both in North America (GFCI & AFCI country) as well as the 
EuroZone (RCD devices).  

   I worked with a student project last year which published a 
paper for the 2017 IEEE PSES ISPCE Symposium; Yuen et al, ‘Why do GFCIs keep 
tripping’.  This paper show that some GFCIs can be tricked into operating when 
they shouldn’t.  

   The non-sinusoidal nature of the earth/ground current as well as 
the CM/DM signals have not been fully understood nor taken care of in a 
harmonized way between the protection device and the load.  

   Lot’s of opportunity here for investigation and recommendation 
of mitigation techniques.  

:>) br,  Pete

Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 23427
Tigard, ORe  97281-3427

503/452-1201

IEEE Life Fellow
mailto:p.perk...@ieee.org

From: Kunde, Brian [mailto:brian_ku...@lecotc.com] 
Sent: Tuesday, January 30, 2018 2:04 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] GFCI vs GFPE

I’ve recently come to understand that the 30mA Ground-Fault protectors, often 
built into a circuit breaker, is intended to protect the Protective Earth 
(Safety Ground) circuit in the case of a short circuit (opening the circuit 
before the safety ground could be damaged.  It this correct?

Here is my question. I’m evaluating a cut-off saw (5hp) which uses water to 
keep the blade and material cool.  The manufacturer uses a 3-phase 
supplementary circuit breaker which includes the 30mA GFPE option.  This is a 
very expensive part.  When I asked them why they use the GFPE part, they 
couldn’t give me a good answer.  

Would such a part be required on a 3-phase motor driven cutoff saw in either 
North America or Europe?  What standard would dictate this?  

If the only purpose of a GFPE is to protect the Ground Circuit, on products 
that can handle shorts without damaging the ground circuit, would a GFPE still 
be necessary?

Where are GFPE typically used? What industry?  

Please educate me.  This is a new one on me.

Thanks,
Brian

From: Doug Nix [mailto:d...@ieee.org] 
Sent: Friday, January 26, 2018 2:48 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] JOB POSTING - ONTARIO, CANADA

PLEASE CONTACT TED TYCZKA DIRECTLY

A very notable, “high-profile” client who is seeking a Safety & Services 
Sales/Business Development Professional - to join their Machine Services 
Division - the focus of the role is to spearhead/lead the sale of Engineering 
Services related to “functional safety.” 
 
The company sells safety training (workshops), machine assessment/audits, 
engineering design per CSA and/o

Re: [PSES] GFCI vs GFPE

[Ralph McDiarmid]

Agreed, and current carry-carrying of PE and bonding of internal parts must 
meet stringent UL/CSA requirements. (not mA!)  It seems to me that 30mA is 
close to lethal, and the GFCI outlets Listed over here are 6mA trip.  (still a 
painful shock)

Ralph McDiarmid
Product Compliance Specialist
Solar Business
Schneider Electric


From: John Woodgate [mailto:j...@woodjohn.uk] 
Sent: Tuesday, January 30, 2018 2:30 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] GFCI vs GFPE

I don't think that is the reason recognized in Europe. The PE circuit has the 
same (or similar) current-carrying capacity as the line circuit(s), so its 
fault-current capacity for 30 s is very large even for a household supply. I 
think the protector is there to prevent fire and to give some protection 
against electric shock, although the latter is compromised so as to prevent 
nuisance-tripping, which would occur if the trip were set at say 5 mA to give 
much better protection.
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates http://www.woodjohn.uk
Rayleigh, Essex UK
On 2018-01-30 22:03, Kunde, Brian wrote:
I’ve recently come to understand that the 30mA Ground-Fault protectors, often 
built into a circuit breaker, is intended to protect the Protective Earth 
(Safety Ground) circuit in the case of a short circuit (opening the circuit 
before the safety ground could be damaged.  It this correct?
 
Here is my question. I’m evaluating a cut-off saw (5hp) which uses water to 
keep the blade and material cool.  The manufacturer uses a 3-phase 
supplementary circuit breaker which includes the 30mA GFPE option.  This is a 
very expensive part.  When I asked them why they use the GFPE part, they 
couldn’t give me a good answer.  
 
Would such a part be required on a 3-phase motor driven cutoff saw in either 
North America or Europe?  What standard would dictate this?  
 
If the only purpose of a GFPE is to protect the Ground Circuit, on products 
that can handle shorts without damaging the ground circuit, would a GFPE still 
be necessary?
 
Where are GFPE typically used? What industry?  
 
Please educate me.  This is a new one on me.
 
Thanks,
Brian
 
From: Doug Nix [mailto:d...@ieee.org] 
Sent: Friday, January 26, 2018 2:48 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] JOB POSTING - ONTARIO, CANADA
 
PLEASE CONTACT TED TYCZKA DIRECTLY
 
A very notable, “high-profile” client who is seeking a Safety & Services 
Sales/Business Development Professional - to join their Machine Services 
Division - the focus of the role is to spearhead/lead the sale of Engineering 
Services related to “functional safety.” 
 
The company sells safety training (workshops), machine assessment/audits, 
engineering design per CSA and/or TUV Safety requirements (“Regulatory 
Compliance”).  The company also sells Remediation and Repair Services (of 
industrial machines) together with Service Contracts ... to customers in the 
aerospace, automotive, forestry, food & beverage, as well as, the packaging 
sectors. 
 
The Safety & Services/Business Development Professional can work from a home 
office - anywhere in Ontario. A Bachelor of Science in Mechanical or Electrical 
Engineering, together with the sale of Machine Safeguard devices and the 
application of these, would be desired ... together, with some exposure to 
Industrial Automation and perhaps Robotics. The key is to have some knowledge 
of safety components, safety scanners, switches, controllers, etc. as well as 
machine building experience. 
 
The employer (a very reputable, Global entity/brand) ... who provide a very 
competitive base salary, lucrative annual bonus/incentive program vs. results, 
plus monthly car allowance, Benefits, Matching RRSP + (Training, Career 
Opportunities and upward mobility). 
 
They are good people, seek an ambitious self-starter who can cover sales from 
the “shop floor” level to the “C Suite” (Boardroom). The company have 
established Sales Reps across Canada ... who can work with the Safety & 
Services Sales Specialist ... this role requires “consultative and solutions 
oriented selling ability.
 
I will ensure absolute confidentiality. Nice opportunity with a great 
organization and strong, capable leadership. Thanks. 
 
Kind professional regards,
Ted Tyczka

President
Golden Mile Management – Consulting Services
2630 Eglinton Avenue East, Toronto, Ontario M1K 2S3
Tel: (416) 266 - 4434
Email: mailto:t...@gmmcs.com
Website: http://www.gmmcs.com/
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Re: [PSES] Measurement dilemma

[Ralph McDiarmid]

The ground leads of the two probes are “dressed” very differently.  Have a 
close look at the video.

Long ground leads on probes are a problem at RF frequencies or when trying to 
measure high dv/dt waveforms.  I used to removed probe clip, remove the ground 
lead, and then wrap #24 buss wire around the ground collar at the probe tip and 
keep that lead <1 cm (or a short as practicable) 

That’s how we used to characterize the peak-peak voltage “noise” at the output 
of bench power supplies which used HF switch-mode technology.  Measurements 
where done right at the buss bar or output connector with just such a probe, 
modified to keep probe parasitic inductance to a minimum.

At least that’s what I think is going on with Doug’s demonstration.


Ralph McDiarmid
Solar Business
Schneider Electric


From: Doug Smith [mailto:d...@emcesd.com] 
Sent: Friday, January 26, 2018 2:50 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Measurement dilema

Hi All,

Can you explain the result in this video I just made? Scope plots of the same 
two nodes are completely different. Probes and scope are operating normally, no 
problem with the equipment itself.

If you have been to my seminars you know the answer, please do not post the 
answer unless you have not seen this experiment until now.

Hint 1: There are no EM fields radiating from the shielded box affecting the 
probes.
Hint 2: There are no active components inside the box.

https://youtu.be/qj-HBFMEJiY

Doug 


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Re: [PSES] CI Software Flicker/Harmonics

[Ralph McDiarmid]

That’s what we do here, when needed.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Pat Lawler [mailto:plawl...@gmail.com] 
Sent: Thursday, December 21, 2017 6:18 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] CI Software Flicker/Harmonics

Hi Brian,

Can you ask your IT people to disable network access on the XP computer?  It 
would no longer be a risk to the company.  Data transfer would have to be via 
diskette or USB thumbdrive. 

I've worked at other facilities with specialized engineering computers 'off the 
network'.

Pat

On Dec 20, 2017 1:14 PM, "Kunde, Brian" <mailto:brian_ku...@lecotc.com> wrote:
It will be difficult for me to ask what I want without insulting California 
Instruments (Emetek), so I apologize in advance if I fail.  For those of you 
who owns a CI CTS Series for doing Harmonic and Flicker emissions testing, you 
can sympathize.

Our CTS system is currently running off of a Windows XP computer, which is no 
longer supported by MS. So our IT guys/gals are pressuring me to upgrade. I 
contacted CI and found out that my current hardware/software will not run on 
anything newer than XP.  I will once again have to update my A/D card and cable 
and software to THEIR latest which will only run on 32bit Windows 7.

So it is going to cost me $5K-$8KUSD to "upgrade" to CI's latest that will ONLY 
work on a 12 year old operating system and which is due to be unsupported in 
only a few years.

So here is my request. Does anyone out there have another solution that makes 
better sense?  How about a modern A/D system that is compatible with the CI 
PACS and 3rd party software that will run on the latest PC and operating system 
(Win 10)??

Has anyone attempted to write their own software to do harmonics and flicker?  
It seems complicated from reading the standard. Is there a document or paper 
that describes how the data is collected and what math has to be applied to do 
the test?

Is there a 3rd party solution that replaces the CI PACS system but where I 
could still use the CT power supply?

I apologize for my ignorance on this topic. We purchased this "turn-key" system 
about 15 years ago and since it works we never had a reason to become experts 
on how the test results are actually calculated and presented.

Thanks to all for any advice.

The Other Brian




LECO Corporation Notice: This communication may contain confidential 
information intended for the named recipient(s) only. If you received this by 
mistake, please destroy it and notify us of the error. Thank you.

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Re: [PSES] CI Software Flicker/Harmonics

[Ralph McDiarmid]

A co-op computer science student on a work term would probably wrestle that to 
the ground in short order.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: John Woodgate [mailto:j...@woodjohn.uk] 
Sent: Wednesday, December 20, 2017 1:26 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] CI Software Flicker/Harmonics

SECOND RESPONSE
I see you asked about writing software. The math involved in IEC 61000-4-7 and 
IEC 61000-4-15 is incredibly complicated. Of course, it could be re-coded, but 
it would be a major undertaking. The Block 5 math of 61000-4-15 is in fact 
under review at present, not for the first time.
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates http://www.woodjohn.uk
Rayleigh, Essex UK
On 2017-12-20 21:13, Kunde, Brian wrote:

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Re: [PSES] CI Software Flicker/Harmonics

[Ralph McDiarmid]

One way to sidestep the "we want to you upgrade that machine" nagging problem 
is to tell IT that engineering will assume responsibility for the asset and it 
will not be connected (an cannot log-on to) the company's LAN.  

I've told our IT dept "no that computer in the basement does not need 8G of ram 
nor does it need Windows 10, we're happy with it thanks and it only control 
this or that instrument and there is no network connectivity . . .  so kindly 
buzz off" (or words to that effect)  ;^))

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Kunde, Brian [mailto:brian_ku...@lecotc.com] 
Sent: Wednesday, December 20, 2017 1:14 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] CI Software Flicker/Harmonics

It will be difficult for me to ask what I want without insulting California 
Instruments (Emetek), so I apologize in advance if I fail.  For those of you 
who owns a CI CTS Series for doing Harmonic and Flicker emissions testing, you 
can sympathize.

Our CTS system is currently running off of a Windows XP computer, which is no 
longer supported by MS. So our IT guys/gals are pressuring me to upgrade. I 
contacted CI and found out that my current hardware/software will not run on 
anything newer than XP.  I will once again have to update my A/D card and cable 
and software to THEIR latest which will only run on 32bit Windows 7.

So it is going to cost me $5K-$8KUSD to "upgrade" to CI's latest that will ONLY 
work on a 12 year old operating system and which is due to be unsupported in 
only a few years.

So here is my request. Does anyone out there have another solution that makes 
better sense?  How about a modern A/D system that is compatible with the CI 
PACS and 3rd party software that will run on the latest PC and operating system 
(Win 10)??

Has anyone attempted to write their own software to do harmonics and flicker?  
It seems complicated from reading the standard. Is there a document or paper 
that describes how the data is collected and what math has to be applied to do 
the test?

Is there a 3rd party solution that replaces the CI PACS system but where I 
could still use the CT power supply?

I apologize for my ignorance on this topic. We purchased this "turn-key" system 
about 15 years ago and since it works we never had a reason to become experts 
on how the test results are actually calculated and presented.

Thanks to all for any advice.

The Other Brian




LECO Corporation Notice: This communication may contain confidential 
information intended for the named recipient(s) only. If you received this by 
mistake, please destroy it and notify us of the error. Thank you.

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Re: [PSES] Temp rise measurement

[Ralph McDiarmid]

I agree it is a serious omission, but perhaps the technique is so rarely used 
the question doesn't arise?

Thermocouples do a pretty good job IF they are carefully affixed and IF a few 
are placed, at various locations on the winding.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business

From: John Woodgate [mailto:j...@woodjohn.uk] 
Sent: Tuesday, December 19, 2017 9:00 AM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Temp rise measurement
 
Yes, there is a much better method. It measures the average temperature of the 
whole winding, rather than the temperature at a particular spot. IEC 62368-1 
incorrectly says that the thermocouple method measures the average temperature. 
You will find it explained in Annex E of IEC 60950-1. Incredibly, both IEC 
60065 and IEC 62368-1 refer to the 'resistance method' without either detailing 
it or providing a cross reference. This is a serious omission.

John Woodgate OOO-Own Opinions Only

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Re: [PSES] Temp rise measurement

[Ralph McDiarmid]

Scott, as far as I know, no safety standard requires you to embed the 
thermistors.  They can be placed on the surface of the winding.  Then your 
temperature limit is reduced from the UL/IEC insulation rated value.  For 
example, in IEC60335-1, temperature limit on Class B (130) insulation is 
limited to 85C rise (in 25C ambient) using thermocouple method.  

The discrepancy accounts for hotspots inside the coil which may be much warmer 
than the coil surface measurement.  See table 3 in that standard and read all 
its notes.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Scott Xe [mailto:scott...@gmail.com] 
Sent: Tuesday, December 19, 2017 8:12 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Temp rise measurement

I will be conducting the temp rise measurements on windings of AC motors for 
electrical appliances such as washing machines, dishwashers, etc.  It said the 
thermal couple method is commonly adopted for safety assessment.  I can 
dismantle the windings and place the couples inside the windings using 
cyanoacrylate adhesive.  However it may change the original shape of windings 
giving non representative measurement result.  Is there any practically 
acceptable solution?

Does the measurement result include the overshoot temperature after the power 
is cut?

Thanks and regards,

Scott

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Re: [PSES] Li-Fi

[Ralph McDiarmid]

Sure, but fiber optics are special purpose, dedicate circuits.  Isn't this 
fella talking about using existing luminaire in the home for data transmission? 
   Maybe I don't know enough about his concept.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: John Woodgate [mailto:j...@woodjohn.uk] 
Sent: Monday, December 11, 2017 8:41 AM
To: Ralph McDiarmid ; 
EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Li-Fi

LED light can indeed be modulated very quickly.  Isn't that how fibre-optic 
cable works?
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates http://www.woodjohn.uk
Rayleigh, Essex UK
On 2017-12-11 16:20, Ralph McDiarmid wrote:
I haven't studied it, but seems to me that one would need to modulate the light 
very quickly to get any sort of usable BAUD rate, unless you settle for 
transmission of text only.  (like the good old Bell 202 modems over voice band 
land lines)

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Amund Westin [mailto:am...@westin-emission.no] 
Sent: Monday, December 11, 2017 12:51 AM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Li-Fi

I came over this video 
https://www.ted.com/talks/harald_haas_a_breakthrough_new_kind_of_wireless_internet#t-432451

Anyone who have studied this tech?

Cheers,
Amund

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Re: [PSES] Li-Fi

[Ralph McDiarmid]

I haven't studied it, but seems to me that one would need to modulate the light 
very quickly to get any sort of usable BAUD rate, unless you settle for 
transmission of text only.  (like the good old Bell 202 modems over voice band 
land lines)

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Amund Westin [mailto:am...@westin-emission.no] 
Sent: Monday, December 11, 2017 12:51 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Li-Fi

I came over this video 
https://www.ted.com/talks/harald_haas_a_breakthrough_new_kind_of_wireless_internet#t-432451

Anyone who have studied this tech?

Cheers,
Amund

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Re: [PSES] Pilot rating

[Ralph McDiarmid]

Just a couple of points:

1. Inductive loads, like a relay coil, don’t have an inrush current, capacitors 
do.  Inductors need controlled de-energization (e.g. placing Zener across them 
or a snubber circuit)

2. Many SSRs do not switch correctly with high PF (large phase angle loads) 
like a.c. relay coils.  (i.e. where zero cross of voltage and current do not 
coincide)

We learned #2 the hard way when trying to switch in/out inductors in an LRC 
load bank using SSRs.  We ended up building a custom mosfet a.c. switch to open 
very close to zero cross on current  (and zero cross on voltage for capacitive 
elements)

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Peter Tarver [mailto:ptar...@enphaseenergy.com] 
Sent: Friday, December 08, 2017 5:23 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Pilot rating

Hi, Jon.

Switching a contactor or relay coil does involve an inrush current and 
inductive kickback, as previously mentioned. This can affect air gap contacts 
in significant ways.

For solid state switching, I’m less familiar with the ins and outs, but if you 
look at some SSR manufacturers’ web sites, you can see that there are different 
P/Ns within a family of SSRs, depending on the nature of the switched load. For 
example, use

http://www.crydom.com/en/tools/parametric-search.shtml?type=panel

to go through some examples. 

Also, check out (not very detailed, but it gives a flavor)

http://www.eaton.com/ecm/idcplg?IdcService=GET_FILE&allowInterrupt=1&RevisionSelectionMethod=LatestReleased&noSaveAs=0&Rendition=Primary&dDocName=AP04901001E

There are bound to be some snubbing features built into these SSRs, just as 
there would be for an electromechanical relay.

A lot of SSRs are zero crossing types to prevent switching on higher voltages. 
This can prolong the life of the SSR.

It could simply be clever marketing to change a P/N, but it might also be that 
there’s a physical difference in the SSRs that make them better suited to 
certain types of loads.

It may be that your design satisfies all of the necessaries for piloting a 
contactor of a certain VA rating. An NRTL will likely want to do some testing 
to satisfy themselves that the special concerns are met by your design. If your 
company is not planning to sell the solid state switch, you can probably 
negotiate a reduced test program based on your application. If you do 
negotiate, make sure you build in some head room for load changes so you don’t 
have to repeat testing when someone gets a clever idea for how to repurpose 
your design.


Regards,

Peter Tarver

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Friday, December 08, 2017 13:09
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Pilot rating


The ultimate issue is what safety issue occurs if the contactor fails to open 
or close when it is supposed to?  If there is no safety consequence, then the 
contactor control is functional, not a safeguard.  If there is a safety 
consequence, then the circuits controlling the contactor constitute a safeguard 
and must be “reliable,”  and must meet the intent of the standard.

Not so cynical Rich


From: Jon Keeble [mailto:j...@wattwatchers.com.au] 
Sent: Thursday, December 7, 2017 12:29 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Pilot rating

I am using a Panasonic AQH3213A PhotoMOS optical isolator to control a small 
contactor.

At 110VAC the contactor coil draws 30mArms.
The coil contacts are wired to a PCB via a terminal block plug and socket.

On the PCB is a series 10ohm fusible resistor, and a SMBJ400AC bidirectional 
zener.

When the switch opens at peak current (42mA) there is 0.1J of energy in the 
coil that gets absorbed by the zener.

The zener 
* clamps at a voltage way below the voltage rating of the optoMOS switch.
* is rated at 600W for 8.3msec and is subject to only 13W for a similar period.

The UL test engineer says that the optoMOS should be "pilot duty" rated (the 
part I am using does have this rating).

Does anyone know what triggers the requirement for a "pilot duty" rating?
Is this defined in a standard somewhere?

This useful link identifies "contact rating codes"
https://na.industrial.panasonic.com/blog/what-pilot-duty-rating-how-it-obtained

The lowest rating E300 is for 110V 1.8A (make) 0.3A (break)

Technically speaking, my switch is not connected to the contactor .. there is a 
two-component network in between
Does UL have the capacity or procedures in place to understand and accept a 
circtuit analysis that shows my circuit as safe?

Jon Keeble

Wattwatchers.



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Re: [PSES] Pilot rating

[Ralph McDiarmid]

This is, I think, an informed source and it defines “pilot duty”

https://na.industrial.panasonic.com/blog/what-pilot-duty-rating-how-it-obtained

By the way, if you are driving your relay coil with a small mosfet, many of 
those have an "avalanche rating" and can safely absorb (dissipate) the energy 
stored in the coil during turn-off release.  Could save your circuit cost of 
two zeners.


Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Adam Dixon [mailto:lanterna.viri...@gmail.com] 
Sent: Thursday, December 07, 2017 2:42 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Pilot rating

I only pilot paper airplanes and this isn't my area of expertise, but it looks 
like this potential requirement originates in NEMA ICS 5 "Industrial Control 
and Systems:  Control Circuit and Pilot Devices" and perhaps also in IEC 62314 
(Solid State Relays - as a "control" relay though the word 'pilot' isn't 
specifically stated)   

NEMA ICS-5-2017 has these NEMA and UL standards in the Section 1.1 Reference 
Standards list:

NEMA ICS 1-2000 Industrial Control and Systems: General Requirements
NEMA ICS 1.1-1984 (R1998) Safety Guidelines for the Application, Installation, 
and Maintenance of Solid State Control
ICS 1.3-1986 (R2001) Preventive Maintenance of Industrial Control and Systems 
Equipment
ICS 6-1993 (R2001) Industrial Control and Systems: Enclosures

UL 310-1995 Electrical Quick-Connect Terminals
UL 353-1994 Limit Controls
UL 486E-1994 Equipment Wiring Terminals for Use With Aluminum and/or Copper 
Conductors
UL 508-1999 Industrial Control Equipment
UL 698-1995 Industrial Control Equipment for Use in Hazardous (Classified) 
Locations
UL 873-1994 Temperature-Indicating and -Regulating Equipment

This link gives short but interesting descriptions of the contact constructions 
for mechanical "pilot duty" and "power" types (though unrelated to SSR). 
https://www.totaline.com/dl/PAGE%20D6%20-%20RELAY%20APPLICATION%20DATA.pdf


Cheers,
Adam in Atlanta
mailto:adam.di...@ieee.org


On Thu, Dec 7, 2017 at 4:45 PM, Jon Keeble <mailto:j...@wattwatchers.com.au> 
wrote:
We are getting a somewhat innovative product through UL at the moment.
So there has been quite a lot of discussion and feedback from UL.
But when UL said they thought my little board needed a pilot rating I really 
thought they were joking.

Jon Keeble

On Fri, Dec 8, 2017 at 8:31 AM, <mailto:n6...@comcast.net> wrote:
I looked at the subject line and thought about something completely unrelated – 
pilot ratings.  I have a PP-ASEL IA.  Private Pilot – Airplane, Single Engine, 
Land  Instrument Airplane.  😊  And you?
 
Ghery S. Pettit
 
From: Jon Keeble [mailto:mailto:j...@wattwatchers.com.au] 
Sent: Thursday, December 7, 2017 12:29 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Pilot rating
 
I am using a Panasonic AQH3213A PhotoMOS optical isolator to control a small 
contactor.
 
At 110VAC the contactor coil draws 30mArms.
The coil contacts are wired to a PCB via a terminal block plug and socket.
 
On the PCB is a series 10ohm fusible resistor, and a SMBJ400AC bidirectional 
zener.
 
When the switch opens at peak current (42mA) there is 0.1J of energy in the 
coil that gets absorbed by the zener.
 
The zener 
* clamps at a voltage way below the voltage rating of the optoMOS switch.
* is rated at 600W for 8.3msec and is subject to only 13W for a similar period.
 
The UL test engineer says that the optoMOS should be "pilot duty" rated (the 
part I am using does have this rating).
 
Does anyone know what triggers the requirement for a "pilot duty" rating?
Is this defined in a standard somewhere?
 
This useful link identifies "contact rating codes"
https://na.industrial.panasonic.com/blog/what-pilot-duty-rating-how-it-obtained
 
The lowest rating E300 is for 110V 1.8A (make) 0.3A (break)
 
Technically speaking, my switch is not connected to the contactor .. there is a 
two-component network in between
Does UL have the capacity or procedures in place to understand and accept a 
circtuit analysis that shows my circuit as safe?
 
Jon Keeble
 
Wattwatchers.
 
 
 
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Re: [PSES] Use of LED Spots in EMC Chambers [General Use]

[Ralph McDiarmid]

Series-pass regulator with a simple bridge rectifier is not zero emission, but 
negligible compared to a well-filtered switch-mode PSU.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric

From: John Woodgate [mailto:j...@woodjohn.uk] 
Sent: Wednesday, November 22, 2017 7:44 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Use of LED Spots in EMC Chambers [General Use]

78 series regulators (except 78Sx which are switchers) do produce a little 
noise but I expect you have them well shielded. There are, of course, 'quieter' 
regulators.
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates http://www.woodjohn.uk
Rayleigh, Essex UK
On 2017-11-22 14:49, john.mcauley wrote:
We use LED spots in our anechoic chambers. They are running now for several 
years. 

However we replaced the switcher with a linear PSU. We installed a transformer, 
bridge rectifier and constant current source using an LM7805 in each one. Works 
a treat and they are zero emission. We have had to do a small amount of EMI 
suppression on noise from the diodes. 

The LED is OK. It is DC. 

We never tried the unmodified unit with the cheap and nasty switching constant 
current drive. We assumed they would be totally unsuitable. 

John McAuley
Compliance Engineering International

Sent from my phone.

 Original message 
From: John Allen mailto:09cc677f395b-dmarc-requ...@ieee.org 
Date: 22/11/2017 2:03 PM (GMT+01:00) 
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG 
Subject: Re: [PSES] Use of LED Spots in EMC Chambers [General Use] 

Could there also be various high frequency sources within the lamps themselves 
which would are not filtered by the filters external to the chamber (and the 
lamps may not have properly shielded bodies and/or lenses)?
 
John E Allen
W.London, UK
 
From: John Woodgate [mailto:j...@woodjohn.uk] 
Sent: Wednesday, November 22, 2017 12:10 PM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Use of LED Spots in EMC Chambers [General Use]
 
It's hardly surprising, is it? These lamps are not designed for the very 
special EMC environment of test chambers.  Lamps using a DC supply are 
indicated, but the DC supply itself must be specially filtered and installed 
outside the chamber.
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates http://www.woodjohn.uk
Rayleigh, Essex UK
On 2017-11-22 12:00, Price, Andrew (Leonardo, UK) wrote:
Hi all.
 
Has anyone had experience with using LED Spot lamps in EMC Chambers?
What types/manufacturers would be recommended?
 
Would appreciate help in trying to solve someone's problems with noise during 
radiated emissions.
Test Facility has just had all their chambers converted to LED Spots and they 
are suffering broadband noise issues.
 
Regards
Andy
 
 
 
 
 Andrew Price
 Land & Naval Defence Electronics Division
     Prinicpal Environmental Engineer (EMC)
 
 Leonardo MW Ltd
 Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
 Tel  EMC LAB : +44 (0)1268 883308
 Mobile: +44 (0)7507 854888
 
mailto:andrew.p.price@leonardocompany.commailto:andrew.p.pr...@leonardocompany.com
 leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS / SPACE
 
* Please consider the environment before printing this email.
 
 
 
 

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Re: [PSES] Use of LED Spots in EMC Chambers [General Use]

[Ralph McDiarmid]

That's a great solution Ken.  BTW, do those white cardboard pyramids absorb 
much RF?

Our old 3m chamber uses the blue foam pyramids only and four 60W ceiling 
lights;  fairly dark inside on a good day.   And, the pyramids are held to 
ceiling and walls with Velcro which doesn't really hold very well.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Ken Javor [mailto:ken.ja...@emccompliance.com] 
Sent: Wednesday, November 22, 2017 8:28 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Use of LED Spots in EMC Chambers [General Use]

One really excellent installation relied on the fact that the chamber was 
ferrite tile-lined with an overlay of the white cardboard pyramids.  Thus 
didn't need nearly as much light as ferrite tiles alone or blue cones. LEDs 
were outside the chamber, placed in the end of a plastic light pipe, which in 
turn penetrated into the chamber through a waveguide-beyond-cutoff pipe.
All wiring and all noise outside the chamber.  Brilliant white light within.

Ken Javor
Phone: (256) 650-5261



> From: "Price, Andrew (Leonardo, UK)" 
> 
> Reply-To: "Price, Andrew (Leonardo, UK)" 
> 
> Date: Wed, 22 Nov 2017 12:00:46 +
> To: 
> Conversation: Use of LED Spots in EMC Chambers [General Use]
> Subject: [PSES] Use of LED Spots in EMC Chambers [General Use]
> 
> Hi all.
> 
> Has anyone had experience with using LED Spot lamps in EMC Chambers?
> What types/manufacturers would be recommended?
> 
> Would appreciate help in trying to solve someone's problems with noise 
> during radiated emissions.
> Test Facility has just had all their chambers converted to LED Spots 
> and they are suffering broadband noise issues.
> 
> Regards
> Andy
> 
> 
> 
> 
>  Andrew Price
>  Land & Naval Defence Electronics Division
>  Prinicpal Environmental Engineer (EMC)
> 
>  Leonardo MW Ltd
>  Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
>  Tel  EMC LAB : +44 (0)1268 883308
>  Mobile: +44 (0)7507 854888
>  
> andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com>
>  leonardocomapany.com
> HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS 
> / SPACE
> 
> * Please consider the environment before printing this email.
> 
> 
> 
> 
> 
> This email and any attachments are confidential to the intended 
> recipient and may also be privileged. If you are not the intended 
> recipient please delete it from your system and notify the sender.
> You should not copy it or use it for any purpose nor disclose or 
> distribute its contents to any other person.
> 
> 
> -
> 
> This message is from the IEEE Product Safety Engineering Society 
> emc-pstc discussion list. To post a message to the list, send your 
> e-mail to 
> 
> All emc-pstc postings are archived and searchable on the web at:
> http://www.ieee-pses.org/emc-pstc.html
> 
> Attachments are not permitted but the IEEE PSES Online Communities 
> site at http://product-compliance.oc.ieee.org/ can be used for 
> graphics (in well-used formats), large files, etc.
> 
> Website:  http://www.ieee-pses.org/
> Instructions:  http://www.ieee-pses.org/list.html (including how to
> unsubscribe)
> List rules: http://www.ieee-pses.org/listrules.html
> 
> For help, send mail to the list administrators:
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> Mike Cantwell 
> 
> For policy questions, send mail to:
> Jim Bacher:  
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Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on AC mains ports?

[Ralph McDiarmid]

My assumption as well




Perhaps, but keep in mind  that the impedance specified by 60725 is a maximum 
value that 90% of household service would not exceed.  It might be 1/2 that 
value on average.



Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Monday, November 20, 2017 12:28 PM
To: Ralph McDiarmid ; 
EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?


I suspect the IEC 60725 impedance is at the service entrance, not through the 
breaker box, building wiring, connectors, and power cord.  By the time all 
these resistances are taken into account, I suspect that the total resistance 
is at least twice that specified in IEC 60725.  

Rich

-Original Message-
From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com] 
Sent: Monday, November 20, 2017 10:42 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

According to IEC/TR 60725, 90% of customers in the UK and in Australia, will 
have electricity supply impedance less than or equal to 0.25 + j0.23 ohms.  
That according to a survey or residential service for 230V/50Hz

That tells me that short circuit current would be at least 680A, but could be 
twice that value or higher for some customers

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric



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David Heald: 

Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on AC mains ports?

[Ralph McDiarmid]

According to IEC/TR 60725, 90% of customers in the UK and in Australia, will 
have electricity supply impedance less than or equal to 0.25 + j0.23 ohms.  
That according to a survey or residential service for 230V/50Hz

That tells me that short circuit current would be at least 680A, but could be 
twice that value or higher for some customers

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Brian O'Connell [mailto:oconne...@tamuracorp.com] 
Sent: Monday, November 20, 2017 10:26 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

Mr. Woodgate,

Is there a recently published spec for a 'typical' 230V mains impedance for the 
EU? Have also noted that the source Zs in 61000-4-5 for the instrument seem 
rather high. So what is the basis for 1500A interrupt rating?

For U.S., even for an artificially low-Z electronic AC source, seldom see fault 
currents exceed 200A peak for 120V mains. Conversely, have noted that at over 
100A fault current, any fuse not rated for the 'high' interrupt value will 
probably explode.

So either our ratings are suspect, or perhaps the physics behind the standards 
are not complete?

Brian



From: John Woodgate [mailto:j...@woodjohn.uk]
Sent: Friday, November 17, 2017 11:16 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

I'm afraid that's not so. The short-circuit current of a 20 A circuit is 
normally at least 500 A, maybe 1500 A.
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates www.woodjohn.uk Rayleigh, Essex UK On 2017-11-18 
03:49, Joe Randolph wrote:
Yes, that is a very good point.  I may have misinterpreted what the term 
“adequate breaking capacity” means.  If all it means is that the fuse must be 
able to safely break the short-circuit current, then a 20 Amp, 250 VRMS fuse 
would be fine for use on a 20 Amp, 240 VRMS circuit.
 
Of course, this would not provide much protection against overheating of the 
MOV unless the MOV failed at an effective resistance of less than 12 ohms.  
Anything higher than that would just keep producing heat.
 
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com
 
From: John Woodgate [mailto:j...@woodjohn.uk]
Sent: Friday, November 17, 2017 4:47 PM
To: Joe Randolph ; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?
 
I agree with this step-wise route to failure. But I wonder about the intended 
meaning of 'adequate breaking capacity'. In the context of the fuse standard 
IEC 60027 (multi-part), this means that the fuse must not shatter or arc-over 
with the largest fault current that can be applied to it. It's all about the 
fuse, not about what it is supposed to protect. 
I believe TVSs (BIG diodes with integral heat sink) are much nicer devices to 
use than MOVs. They don't suffer from energetic disruption.
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates www.woodjohn.uk Rayleigh, Essex UK On 2017-11-17 
21:39, Joe Randolph wrote:
I have not performed any actual testing, but I believe that the basic problem 
is that MOV leakage current increases slightly each time the MOV experiences a 
big surge.  So, in the early stages of this mechanism, the leakage current will 
increase step-wise each time the MOV experiences a big surge.
 
In practice, these successive "big surges" could be spaced months or years 
apart.  Each successive surge will increase the leakage current, but if the 
current remains well below the level that causes significant self-heating of 
the MOV, the situation will remain stable.
 
After some number of big surges (which could take years to accumulate), the 
leakage current will have increased enough that the self-heating process itself 
leads to higher leakage current.  This sets up a positive feedback loop that 
causes the MOV to go into thermal runaway and self-destruct.
 
I'm not sure the thermal runaway could be described as an "avalanche," since 
the process might take considerable time to destroy the MOV, but the general 
direction of the failure gets establishes as soon as the positive feedback 
mechanism gets started.  
 
If it could be shown that any dissipation level less than 240 W cannot cause 
ignition of nearby materials, then a 1A fuse would appear to provide the 
"adequate breaking capacity" called for in 60950-1.
 
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com
 
 
-Original Message-
From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com]
Sent: Friday, November 17, 2017 1:05 PM
To: EMC-PSTC@LISTS

Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on AC mains ports?

[Ralph McDiarmid]

I wonder if a 1A fuse would protect against MOV flameout just as well as a 
100mA, if these MOV fail as an avalanche.  (get hotter = more leakage)  
I've seen some standards use 240VA (assume 240W) as a power limit for 
protection against fire.  However, I wonder if a MOV could burn nicely at say 
0.5A without further increase in current.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Joe Randolph [mailto:j...@randolph-telecom.com] 
Sent: Monday, November 13, 2017 7:56 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

Hi Mick:

Annex Q  in 60950-1 shows that the authors were concerned about increased 
leakage current in MOVs that are subjected to multiple surges.  Perhaps the 
authors assumed that if the equipment passed the earth leakage test with new 
MOVs, allowing the MOVs to deteriorate by up to 10% after the Annex Q surges 
would be acceptable.  

Unfortunately, Annex Q does not help to define the term "adequate breaking 
capacity" as called for in clause 1.5.9.2 for fuses required in series with the 
MOV.  As Rich Nute has pointed out, a fuse that will open when the leakage 
current exceeds 0.5 mA cannot be expected to survive a 3 kA surge.

So, the purpose of the fuse does not appear to be directed at the 0.5 mA 
leakage current requirement.  Rather, I think the authors were trying to use 
the fuse to protect against the three conditions itemized in clause 1.5.9.2:

* Temporary overvoltages
* Thermal overload due to increased leakage current
* Burning and bursting of the MOV in the event of a short-circuit fault

The problem with this is that it takes very little leakage current to cause 
thermal overload of the MOV.  At 230 VRMS, and RMS leakage current of 100 mA 
would dissipate 23 Watts in the MOV.  A fuse that reliably opens at 100 mA will 
not survive a 3 kA surge.  

In general, MOVs subjected to thermal overload allow more leakage current as 
they heat up.  With a fixed voltage supply (such as 230 VRMS), this creates a 
positive-feedback condition of ever-increasing power dissipation that 
eventually drives the MOV to destruction.

So, perhaps the requirement for "adequate breaking capacity" was directed at 
trying to prevent burning and busting of the MOV, rather than excessive earth 
leakage current.  So far, it appears that the term "adequate breaking capacity" 
is not actually defined in 60950-1.  I suppose that the authors intended 
"adequate breaking capacity" to mean "adequate to prevent burning and bursting" 
of the MOV.  

I'm not sure that this is even possible if that same fuse has to survive a 3 kA 
combination wave surge.  However, it is possible that 60950-1 does not actually 
require the circuit to survive such surges.  Perhaps all that 60950-1 requires 
is that the MOV itself tolerates such surges with no more than 10% degradation. 
 It would then be left to the product designer to select a suitable fuse.  
Between the conflicting goals of preventing nuisance tripping of the fuse and 
preventing overheating of the MOV, I'm not sure that an ordinary fuse can be 
found that meets both goals.

This may be why 62368-1 seems to be steering us to using a thermal fuse that 
senses overheating of the MOV, rather than a fuse that responds only to current.


Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com


-Original Message-
From: Mick Maytum [mailto:mjmay...@gmail.com]
Sent: Sunday, November 12, 2017 3:55 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

For my sins I am currently editing a 40 page MOV application guide. As the 
guide was written by a Chinese expert I have the additional task of translating 
the Chinlish to English. However this forces understanding and I found the 
document contains many gems I did not appreciate. On degradation three areas 
are mentioned:

1.  Varistor voltage at 1mA has decreased by more than 10 % of the 
initial value.
2.  Surge limiting voltage at a specified impulse current has increased 
by more than 10 % of the initial value.
3.  Leakage current or watt-loss shows a steady increase.

Then the comment is made that generally if the Varistor voltage has decreased 
by 10 %, the limiting voltage will have only increased by 3 %. 
Thus the Annex Q limiting voltage change limit of 10 % would be better replaced 
by a Varistor voltage change.

On fuses I did some calculations and found an anti-surge fuse in the 4 A region 
was required to withstand the Annex Q MOV requirement of a 3 kA
8/20 surge. It should be remembered that most fuses will not interrupt an 8/20 
surge as the fuse link plasma carries on conducing the 8/20 impulse current. 
Ted 

Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on AC mains ports?

[Ralph McDiarmid]

I've see MOVS flame after being hit repeatedly with 6kV combination wave surges 
too quickly  (30s apart),  during type testing to ANSI C62.45

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Joe Randolph [mailto:j...@randolph-telecom.com] 
Sent: Saturday, November 11, 2017 3:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

Hi Rich:

Thanks for your feedback on this topic.  

My impression is that the intent of the requirement for a fuse in series with 
an MOV is not related to concerns about protecting users from surge transients. 
 I believe the intent of the requirement is to protect users from the effects 
of an MOV that has become leaky and is allowing excess current to flow into the 
ground conductor.

While the cause of the MOV becoming leaky is typically considered to be 
degradation caused by surges, the surges themselves are not the focus of the 
requirement for a fuse.  Rather, the focus is on hazards created by leaky MOVs.

Regarding the interpretation of 60950-1, I have two questions:

1) For equipment that has two MOVs, each connected line-to-ground, does 60950-1 
require fusing both of the line leads?  It appears to me that the answer is 
yes, but I'm not an expert on this topic.

2) Clause 1.5.9.2 in 60950-1 requires that the fuse must have "adequate 
breaking capacity."  Where in 60950-1 do we find a definition and/or test for 
"adequate breaking capacity"?

I agree with your observation that if the purpose of the fuse is to keep the 
leakage current under 0.5 mA, there is no practical way to achieve this.  The 
same fuse must also be able to survive the anticipated surge currents for which 
the MOV was installed.

So, the authors of clause 1.5.9.2 must have had some other definition in mind 
for the term, "adequate surge protection."


Thanks,

Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com

-Original Message-
From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Thursday, November 09, 2017 6:34 PM
To: 'Joe Randolph' ; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?


Hi Joe:

"I still have a question about whether clause 1.5.9.2 in 60950-1 means that 
there must be fuses in each of the Line conductors when two MOVs are installed 
line-to-ground on the AC mains input.  It sure looks that way when I read the 
requirement."

I have some doubts as to whether a fuse will open the circuit when an MOV 
conducts.  Or, when the MOV leakage is excessive.  

Continuous current in the earth conductor must not exceed 0.5 mA.  I couldn't 
find any fuses rated less than 32 mA.  So the fuse cannot protect against MOV 
deterioration.  

Supposedly, the MOV operates when the transient voltage exceeds, say, 2100 
volts peak.  When the MOV operates, the line conductor is almost shorted to 
ground.  So, 2100 volts peak across the fuse exceeds its voltage rating by 500% 
(assuming the fuse is rated for the mains voltage).  If you exceed the fuse 
voltage rating, the fuse is not likely reliable, and may become a conductor.  

Another interesting point.  While the standard severely limits the use of an 
SPD for "Type A" plug-connected equipment, the SPD cannot operate if the ground 
is open.  For an injury to occur, three conditions must be met:

1)  Transient voltage exceeding 2100 volts peak (maybe only a few times per 
year).
2)  Person touching an otherwise grounded part of the equipment.
3)  The transient voltage must have enough energy to cause an injury.  

The probability of an injury is the multiplication of the individual 
probabilities.  Very small.

If the transient waveform is the standard transient waveform, 1.2 usec x 50 
usec, then the duration is much shorter than the curves shown in IEC 60479-5.  
So, there is insufficient energy in the transient waveform to cause an injury.

Best regards,
Rich

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This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 


All emc-pstc postings are archived and searchable on the web at:
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Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

Website:  http://www.ieee-pses.org/
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List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:
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Jim Bacher:  
David Heald: 

Re: [PSES] Clicks per CISPR 14-1

[Ralph McDiarmid]

Indeed, why not merely add a Peak limit or perhaps better, an Average limit?  
Doing that would avoid an effort to clarify the issue with words.  Avg & QP 
limits have served well in CISPR11 and in CISPR22 for a long time.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Paolo Roncone [mailto:paoloc...@gmail.com] 
Sent: Friday, November 10, 2017 4:52 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Clicks per CISPR 14-1

Agree, but that would be a bit too clear...I think there's an office somewhere 
within IEC whose mission is to maximize the intricacy of something already 
intricate
An alternative, but maybe too simple and easy, would be to add peak limits for 
conducted EMI, higher than QP and Average..

Best regards,
Paolo

On Fri, Nov 10, 2017 at 1:42 PM, John Woodgate <mailto:j...@woodjohn.uk> wrote:
I still say that the wording of 3.3.3 is not as rigorous as it should be. It 
should read something like: "discontinuous disturbance, the amplitude of which, 
measured with the QP receiver, exceeds the quasi-peak limit for continuous 
disturbance, the duration of which is NOT LONGER than 200 ms and which is 
separated from a subsequent disturbance by at least 200 ms,...". Without that 
clarification, if the amplitude exceeds the limit for however short a time, the 
disturbance is a click.
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates http://www.woodjohn.uk
Rayleigh, Essex UK
On 2017-11-10 12:30, Paolo Roncone wrote:
Hi John, 

I see only an upper duration limit (200 msec), because clicks are 
referenced/measured only with a QP detector. See CISPR 14-1 sec.C2.2 "The 
amplitude of the clicks shall be measured with a receiver having a quasi-peak 
detector according to Clause 4 of CISPR 16-1-1:2015." 
So clicks shorter than 1 ms would not be picked up by a QP detector or at least 
never charge it high enough to reach the QP limit...that's my guess. 

Best regards,
Paolo


On Fri, Nov 10, 2017 at 12:06 PM, John Woodgate <mailto:j...@woodjohn.uk> wrote:
I think the 1 ms attack time ensures that the click is detected. But there is 
an issue with the wording. It appears that a 0.5 ms pulse above the QP  limit 
is a click as defined , but is too short compared with the QP rise-time to show 
 as exceeding the limit. I think there should be a lower limit of duration as 
well as the 200 ms upper limit.
But this probably doesn't help.
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates http://www.woodjohn.uk
Rayleigh, Essex UK
On 2017-11-10 10:37, Paolo Roncone wrote:
Hi all,

Question: 
IF the EUT Mains conducted emissions Quasi-peak levels are under the CISPR 14-1 
Quasi-peak limit (CISPR 14-1 Table 5), when measured with a CISPR 16-1-1 
compliant EMI receiver, is the click procedure/assesment deemed to be complied 
with, or not?
In other words, is there in a PASS case still the need to go through the very 
complicated procedures detailed in sections 4.4, Fig.6 (Flow diagram) and Annex 
C of CISSPR 14-1 for determining, analyzing, measuring and assessing compliance 
of clicks ?

Going through CISPR 14-1 (2016 ed.):
Section 4.4.1 says: "Discontinuous disturbances shall be assessed WHEN they 
exceed the limits for continuous disturbances,.."
Click definition in sec.3.3.3: "discontinuous disturbance, the amplitude of 
which exceeds the quasi-peak limit for continuous disturbance, the duration of 
which is NOT LONGER than 200 ms and which is separated from a subsequent 
disturbance by at least 200 ms,..." 

Now, the charge/discharge times of a Band B (150k-30M) QP receiver = 
1msec/160msec, so a click lasting less than 160msec (see click examples in 
Fig.2 of CISPR 14-1) yet exceeding the QP limit might NOT be picked up by the 
QP receiver during a standard mains conducted EMI measurement..here is the 
origin of my doubts. 

Thanks in advance for any feedback
Paolo
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This message is

Re: [PSES] "persons" in IEC 62368-1

[Ralph McDiarmid]

A very nice clarification; thanks Rich.

As a case in point, I know of a least one high school in this jurisdiction 
where students (instructed persons) are allowed to assemble and test circuits 
consisting of magnitude 3 energy sources.  I wonder if the school board needs 
to review that practice, since the principles of electric circuits can be 
taught just as effectively using magnitude 1 energy sources.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


-Original Message-
From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Thursday, November 09, 2017 1:04 PM
To: Ralph McDiarmid ; 
EMC-PSTC@LISTSERV.IEEE.ORG
Subject: "persons" in IEC 62368-1


In IEC 62368-1, three different persons are defined with respect to their 
knowledge of safety, not with respect to other parameters.

An "ordinary person" is naïve with regard to the safety of the equipment.  
Therefore, an "ordinary person" must have the full protections specified in the 
standard.  "Ordinary person" is defined in the IEC Glossary, 

http://std.iec.ch/terms/terms.nsf/3385f156e728849bc1256e8c00278ad2/e6936aca232ebc83c1257cac004ac0a7?OpenDocument

A "skilled person" is an expert with regard to the safety of the equipment.  He 
is "expected to use their training and experience to recognize energy sources 
capable of causing pain or injury and to take action for protection from injury 
from those energies."  None of the protections specified in the standard are 
applicable to a "skilled person."  He can work on the equipment with the covers 
off.   Ralph worked on TVs with the covers off and was able to avoid injury 
because of his knowledge of the energy sources, so, with respect to TV safety, 
he was a "skilled person."  "Skilled person" is also defined in the IEC 
Glossary.

An "instructed person" is just that.  He must be instructed as to energy 
sources that could cause pain and the precautions he must use to avoid the 
pain.  And, he cannot be exposed to energy sources that could cause injury.  
Instruction must be by someone who knows the energy sources in the specific 
equipment and knows the precautionary measures that must be taken to avoid 
pain, which means that the instruction must be by a "skilled person."  
"Instructed person" is defined in the IEC Glossary.

Associated with the person definitions, IEC 62368-1 defines three magnitudes of 
energy.  Magnitude 1 may be detectable, but not likely to cause pain or injury. 
 An "ordinary person" may have exposure to magnitude 1 energy sources, e.g., 
low voltage.  

Magnitude 2 may cause pain, but not likely to cause injury.  An "instructed 
person" may (is allowed to) have exposure to magnitude 2 energy sources.

Magnitude 3 may cause injury.   A "skilled person" may have exposure to 
magnitude 3 energy sources, e.g., mains voltages.

Rich

-Original Message-
From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com] 
Sent: Wednesday, November 1, 2017 2:38 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

IEC 63386-1 seems to introduce a lot of new terms I have not seen used in other 
IEC standards.  ( but I haven't read everything out there) I would add that a 
"skilled person" perhaps is a "qualified person" , but qualification is often 
associated with formal training by an accredited institute, not just on-the-job 
experience.  I have fixed a few TVs in my time, but I wouldn't say I was 
qualified; skilled maybe.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric
 


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Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on AC mains ports?

[Ralph McDiarmid]

IEC 63386-1 seems to introduce a lot of new terms I have not seen used in other 
IEC standards.  ( but I haven't read everything out there)
I would add that a "skilled person" perhaps is a "qualified person" , but 
qualification is often associated with formal training by an accredited 
institute, not just on-the-job experience.  I have fixed a few TVs in my time, 
but I wouldn't say I was qualified; skilled maybe.

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric
 

-Original Message-
From: Joe Randolph [mailto:j...@randolph-telecom.com] 
Sent: Wednesday, November 01, 2017 12:02 PM
To: Ralph McDiarmid ; 
EMC-PSTC@LISTSERV.IEEE.ORG
Subject: RE: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

The definition of "reliable earthing" appears in clause 5.6.7 of 62368-1, and 
it seems reasonable.  Equipment that has a permanent earth connection, or 
equipment with an industrial "Type B" plug, is considered to have a reliable 
earth connection.  However, for the ordinary "Type A" plugs used on consumer 
equipment such as toasters and computers, the fact that the plug has a ground 
pin is not considered, by itself, to provide a reliable earth connection.  This 
is because users sometimes intentionally defeat these ground connections, and 
household outlets are sometimes not properly grounded.

So, clause 5.6.7 contains a complex description of what special circumstances 
will allow a Type A plug to be considered a reliable earth connection.  An 
example would be if the equipment is installed by a "skilled person," such as a 
professional installer.

What this leaves us with is that ordinary consumer equipment that has a Type A 
plug and is installed by the user is *not* considered to provide a reliable 
earth connection.  Since the earth connection is not considered to be reliable, 
a series GDT is required to help protect against excessive touch currents.

I mentioned in my original post that I have seen GDTs placed in series with 
MOVs, but did not know why this was being done.  Apparently it is being done to 
deal with potentially high leakage currents in equipment that does not have a 
reliable earth connection.

I still have a question about whether clause 1.5.9.2 in 60950-1 means that 
there must be fuses in each of the Line conductors when two MOVs are installed 
line-to-ground on the AC mains input.  It sure looks that way when I read the 
requirement.


Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com

-Original Message-
From: Ralph McDiarmid [mailto:ralph.mcdiar...@schneider-electric.com]
Sent: Wednesday, November 01, 2017 12:24 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Regulatory requirements for MOVs placed line-to-ground on AC 
mains ports?

The term Reliable Earthing is an interesting one.  Does it mean that the 
earthing bond is not expected to fail (single fault) and so provides two levels 
of protection, as in ‘reinforced” ?   I remember arguing this point many years 
ago in a product safety review at another company and meeting some considerable 
resistance (no pun intended)

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Joe Randolph [mailto:j...@randolph-telecom.com]
Sent: Tuesday, October 31, 2017 9:43 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

Thanks everyone for the helpful input.  If I am understanding the situation 
correctly, it can be loosely summarized as follows:


IEC 60950-1

Clause 1.5.9.2

MOVs connected mains-to-earth or across the mains must have a fuse in series.  
The fuse must have “adequate breaking capacity.”

There is no mention of requiring a GDT in series with an MOV.


IEC 62368-1

Clause 5.5.7

MOVs connected mains-to-earth may be connected directly to earth only if that 
earth is “reliable” (such as a permanently connected earth).

If the earth connection is not “reliable” (earthing obtained through the 
earthing pin of ordinary Pluggable Type A connecter is not considered 
“reliable”), MOVs connected mains-to-earth must have a GDT in series, 
presumably to protect against excessive leakage current.


Annex G.8

To protect against the risk of fire, MOVs are subjected to a series of tests 
designed to overheat them and induce fire.  While series fuses are not 
explicitly required, the inclusion of a series fuse can be helpful for passing 
the tests of G.8



SUMMARY

The above summarizes my current understanding of the requirements regarding 
components to be used in series with MOVs when the MOVs are connected to the AC 
mains.  While IEC 60950-1 requires series fuses, it does not seem to require 
series GDTs

IEC 62368-1 requires series GDTs if the earth connection is not “reliable,” an

[PSES] Regulatory requirements for MOVs placed line-to-ground on AC mains ports?

[Ralph McDiarmid]

The term Reliable Earthing is an interesting one.  Does it mean that the 
earthing bond is not expected to fail (single fault) and so provides two levels 
of protection, as in ‘reinforced” ?   I remember arguing this point many years 
ago in a product safety review at another company and meeting some considerable 
resistance (no pun intended)

Ralph McDiarmid
Product Compliance
Engineering
Solar Business
Schneider Electric


From: Joe Randolph [mailto:j...@randolph-telecom.com] 
Sent: Tuesday, October 31, 2017 9:43 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

Thanks everyone for the helpful input.  If I am understanding the situation 
correctly, it can be loosely summarized as follows:


IEC 60950-1

Clause 1.5.9.2

MOVs connected mains-to-earth or across the mains must have a fuse in series.  
The fuse must have “adequate breaking capacity.”

There is no mention of requiring a GDT in series with an MOV.


IEC 62368-1

Clause 5.5.7

MOVs connected mains-to-earth may be connected directly to earth only if that 
earth is “reliable” (such as a permanently connected earth).

If the earth connection is not “reliable” (earthing obtained through the 
earthing pin of ordinary Pluggable Type A connecter is not considered 
“reliable”), MOVs connected mains-to-earth must have a GDT in series, 
presumably to protect against excessive leakage current.


Annex G.8

To protect against the risk of fire, MOVs are subjected to a series of tests 
designed to overheat them and induce fire.  While series fuses are not 
explicitly required, the inclusion of a series fuse can be helpful for passing 
the tests of G.8



SUMMARY

The above summarizes my current understanding of the requirements regarding 
components to be used in series with MOVs when the MOVs are connected to the AC 
mains.  While IEC 60950-1 requires series fuses, it does not seem to require 
series GDTs

IEC 62368-1 requires series GDTs if the earth connection is not “reliable,” and 
it’s fire safeguard tests seem to encourage the use of series fuses, although 
fuses are not explicitly required in order to pass the tests.

I would appreciate any additional input that might help me determine whether 
the above interpretations are correct.


Thanks,

Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
mailto:j...@randolph-telecom.com
http://www.randolph-telecom.com

From: John Allen [mailto:09cc677f395b-dmarc-requ...@ieee.org] 
Sent: Tuesday, October 31, 2017 10:15 AM
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

Having had a look at 62368-1 Ed 2, I think the relevant clause in that is 
5.5.7. “SPDs” (“Surge Protective Devices”), 

5.5.7.1 “Use of an SPD between the mains and earth”
“Where a varistor is used between the mains and earth:
– the earth connection shall comply with 5.6.7; and
– the varistor shall comply with Clause G.8.”

Cl 5.6.7 “Reliable Earthing” could be important as that gives  familiar  
“reliable earthing” methods for some equipment.

5.5.7.2 “Use of an SPD connected to reliable earthing”
“Where an SPD is used between the mains and protective earth, it shall consist 
of a varistor
and a GDT connected in series, where the following applies:
– the varistor shall comply with Clause G.8;
– the GDT shall comply with:
• the electric strength test of 5.4.9.1 for basic insulation; and
• the external clearance and creepage distance requirements of 5.4.2 and 5.4.3
respectively for basic insulation.
NOTE 1 Some examples of SPDs are MOVs, varistors and GDTs. A varistor is 
sometimes referred to as a VDR or
a metal oxide varistor (MOV).
The above requirements do not apply to SPDs:
– intended for attenuating transient voltages from external circuits; and
– connected to reliable earth (see 5.5.7.1).”

The last bit is interesting because it “seems” to exempt SPDs from needing GDT 
protection in some circumstances – or am I misreading it?

Annex G8 “Varistors” then give detailed requirements & tests for such devices.

John E Allen
W.London, UK

From: Mick Maytum [mailto:mjmay...@gmail.com] 
Sent: 31 October 2017 10:50
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on 
AC mains ports?

Joe,
    I'm away from my data at present. I think IEC 62368-1 in clause 1 states 
that where a consistent connection to PE/ground cannot be guaranteed, such as 
with pluggable equipment, protection from mains to the PE requires to be a GDT 
and varistor to be connected in series.
   

 
Regards,
Mick Maytum
Safety and Telecom
Standards
mailto:mjmay...@gmail.com
http://www.ictsp-essays.info

-- Original Message --
From: "Joe Randolph" <mailto:j...@randolph-telecom.com>
To: mailto:EMC-PSTC@listserv.ieee.org
Sent: 31/10/2017 02:09:14
Subject: [PSES] Regulatory requirements for MOVs