Re: [PSES] Simulation of signal source under a pwb shield

[James Pawson (U3C)]

Hi Charles,

 

Why not flip it around? The circuit under your shield is an antenna which will 
be as good at receiving as transmitting. Illuminate the circuit with a known 
field intensity (radiated RF immunity test IEC 61000-4-3 for example) and 
measure the noise voltage at the key point on the circuit (RF connector).

 

If you are still working on satellite tuners then presumably you are worried 
about in-band signals? Generating fields in the low GHz with a decent spec of 
signal generator, a horn antenna, and reducing the distance could work, even in 
a non shielded environment. Calibrating field strength would need maths or an 
electric field probe at the required distance.

 

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.

 

 

 

 

From: Chas Grasso  
Sent: Friday, July 21, 2023 8:39 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Simulation of signal source under a pwb shield

 

Hello experts and gurus!!


I need to simulate the performance of a BLS (board level shield) and I am 
considering
using the IEEE Std 2716-2022 IEEE Guide for the Characterization of the 
Effectiveness of Printed Circuit Board Level Shielding document. This document 
is however an adaptation of 
the methods of evaluating gaskets rather than a focused guide on BLS 
performance.

Question: Does anyone have experience using this Guide as intended for a BLS 
solution evaluation? 

Another Question: Would someone guide me to a paper or experiment that shows 
a decent correlation of a simulated source in a BLS versus actual measurements ?


Here's my concern: The problem of how to internally  source a signal for 
simulation and
measurement seems deceptively simple. Just put an antenna on the inside of the 
shield - right? Well, no. My concern is that the addition of the shield 
compromises 
the antenna characteristics and so inadvertently this results in better (or 
worse) results.

 

With eager anticipation and appreciation for your help with this!!

-- 

Charles Grasso

Dish Technologies

 (c) 303-204-2974

(w) 303-706-5467

(h) 303-317-5530

(e ) charles.gra...@dish.com  

(e2) chasgra...@gmail.com  

  _  

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Re: [PSES] Immunity test field strength, residential setting

[David Schaefer]

IEC 62061 is for safety related control systems, and also calls out swept 20 
V/m for 80-1000 MHz. It doesn’t seem an unreasonably high level for testing, 
particularly in industrial environments that may have higher emissions.

IEC 62061:2021 specifies requirements and makes recommendations for the design, 
integration and validation of safety-related control systems (SCS) for 
machines. It is applicable to control systems used, either singly or in 
combination, to carry out safety functions on machines that are not portable by 
hand while working, including a group of machines working together in a 
co-ordinated manner.


[cid:image912885.jpg@FE3CD5A9.160173B5]
David Schaefer​
Technical Manager
Element Materials Technology
9349 W Broadway Ave
Brooklyn Park
,
MN
55445
,
United States
O +1 612 638 5136
ext. 10461
david.schae...@element.com
www.element.com
[cid:image090487.png@7D6784CD.3C04433D]
[cid:image914461.png@DFCDFFDD.0FA1422A]
[cid:image061216.png@8CE2C878.662C4A8C]
[cid:image891303.png@FF411299.B159A737]
[cid:image964301.jpg@0A7F6A0F.D9CD69CE]
From: T.Sato [mailto:vef00...@nifty.com]
Sent: Friday, July 21, 2023 7:21 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Immunity test field strength, residential setting


CAUTION:This email originated from outside of Element Materials Technology. DO 
NOT click links or open attachments unless you recognize the sender and know 
the content is safe. Please contact IT Service Desk if you are in any doubt 
about this email.
On Fri, 21 Jul 2023 16:44:29 GMT,
Brian Gregory mailto:brian_greg...@netzero.net>> 
wrote:

...
> We are building EV Chargers for residential markets (not just US)
> and one of the safety applicable standards is UL 2231-2. It calls
> out IEC 61000-4-3 for immunity testing parameters, which states a
> requirement for a field strength of 20V/m.
...
> Can some offer this "DC guy" (aka, 60 Hz) a
> quick definition of what the 20V/m represents?
...

It appears the standard is for personnel protection devices for use in
charging systems, and not for other aspects of the EV chargers.

Safety-related standards sometimes call for higher immunity test levels.
For example, IEC 61000-6-7 calls for 20 V/m per IEC 61000-4-3 test method.

Also, although the regulation will not usually be required in US and
charging stations will not be covered by the regulation anyway, ECE R1
calls for 30 V/m per ISO 11451-2 also in charging mode.

I don't know of the rationale, but I think 20 V/m is not unreasonably high
to test safety aspects of the charging systems.

Regards,
Tom


On Fri, 21 Jul 2023 16:44:29 GMT,
Brian Gregory mailto:brian_greg...@netzero.net>> 
wrote:

> Hello colleagues, We are building EV Chargers for residential markets (not 
> just US) and one of the safety applicable standards is UL 2231-2. It calls 
> out IEC 61000-4-3 for immunity testing parameters, which states a requirement 
> for a field strength of 20V/m. Our EMC expert says typically testing is "done 
> at 3 Vrms, which is standard for most products in residential environments." 
> He can only test up to 10V, and we're hearing the same from an overseas lab 
> to whom our manufacturer refers. Does FCC Part B have guidelines for field 
> strength we can cite? Can some offer this "DC guy" (aka, 60 Hz) a quick 
> definition of what the 20V/m represents? I'm guessing 20 V/m is for higher 
> density commercial applications, aka charging stations, so we probably need 
> an exception for residential. Thank you! Colorado Brian
> 720-450-4933
>
> -
> 
> 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 
> mailto:emc-p...@ieee.org>>
>
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Re: [PSES] Simulation of signal source under a pwb shield

[Chas Grasso]

Hello All and Thank you for all your help. !! The knowledge base here is
exceptional!

On Mon, Jul 24, 2023 at 1:29 AM James Pawson (U3C) <
ja...@unit3compliance.co.uk> wrote:

> * This message originated outside of DISH and was sent by:
> ja...@unit3compliance.co.uk  *
> --
>
> Hi Charles,
>
>
>
> Why not flip it around? The circuit under your shield is an antenna which
> will be as good at receiving as transmitting. Illuminate the circuit with a
> known field intensity (radiated RF immunity test IEC 61000-4-3 for example)
> and measure the noise voltage at the key point on the circuit (RF
> connector).
>
>
>
> If you are still working on satellite tuners then presumably you are
> worried about in-band signals? Generating fields in the low GHz with a
> decent spec of signal generator, a horn antenna, and reducing the distance
> could work, even in a non shielded environment. Calibrating field strength
> would need maths or an electric field probe at the required distance.
>
>
>
> 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.*
>
>
>
>
>
>
>
>
>
> *From:* Chas Grasso 
> *Sent:* Friday, July 21, 2023 8:39 PM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* [PSES] Simulation of signal source under a pwb shield
>
>
>
> Hello experts and gurus!!
>
>
> I need to simulate the performance of a BLS (board level shield) and I am
> considering
> using the IEEE Std 2716-2022 IEEE Guide for the Characterization of the
> Effectiveness of Printed Circuit Board Level Shielding document. This
> document is however an adaptation of
> the methods of evaluating gaskets rather than a focused guide on BLS
> performance.
>
> Question: Does anyone have experience using this Guide as intended for a
> BLS solution evaluation?
>
> Another Question: Would someone guide me to a paper or experiment that
> shows
> a decent correlation of a simulated source in a BLS versus actual
> measurements ?
>
>
> Here's my concern: The problem of how to internally  source a signal for
> simulation and
> measurement seems deceptively simple. Just put an antenna on the inside of
> the
> shield - right? Well, no. My concern is that the addition of the
> shield compromises
> the antenna characteristics and so inadvertently this results in better
> (or worse) results.
>
>
>
> With eager anticipation and appreciation for your help with this!!
>
> --
>
> Charles Grasso
>
> Dish Technologies
>
>  (c) 303-204-2974
>
> (w) 303-706-5467
>
> (h) 303-317-5530
>
> (e ) charles.gra...@dish.com
>
> (e2) chasgra...@gmail.com
> --
>
> 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
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>
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>
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> --
>
> To unsubscribe from the EMC-PSTC list, click the following link:
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>


-- 

Charles Grasso

Dish Technologies

 (c) 303-204-2974

(w) 303-706-5467

(h) 303-317-5530

(e ) charles.gra...@dish.com

(e2) chasgra...@gmail.com

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Re: [PSES] Stability

[Douglas Nix]

Hi Steve,

IMO, EN 60204-1 is the wrong standard. You said that the cart is used in a lab 
setting. You need to use a lab equipment standard, and for the EU EN 61010-1 is 
the correct choice.

If not that, then you really need to add a bunch of additional machinery 
related standards, which I also think is the wrong choice since the cart 
doesn’t sound like it meets the definition of a machine.

--
Doug Nix
d...@mac.com
(519) 729-5704

"Our greatest weakness lies in giving up. The most certain way to succeed is 
always to try just one more time." - Thomas Edison



> On Jul 22, 2023, at 15:51, Steve Brody  wrote:
> 
> A client has a product which is a mobile cart intended for a laboratory 
> setting in which it can be moved to whatever lab station it is needed at.  It 
> is on casters and when wheeled to the working location, leveling feet which 
> are located in the center of the castor mount, are lowered and locked into 
> position to keep the cart from moving and to ensure it is level.
> 
> The product will be evaluated to EN 60204-1, but there is no reference to 
> stability in this standard.
> 
> First question is should EN 61010-1, 7.4, be used to evaluate stability, and 
> if not then what?
>  
> Assuming yes, the first sentence of 7.4 says; 'Equipment and assemblies of 
> equipment not secured to the building structure before operation should be 
> physically stable.'
>  
> Second question is does this section apply to the cart only when in position 
> for use, or also when being moved from location to location? 
>  
> Because when in use the cart is supported by [properly rated] feet, then the 
> tests for castors should no longer apply?.
> 
> That is the third question.
>  
> Your thoughts and comments are requested and appreciated, as always. 
>  
> Thanks,
>  
> Steve Brody
> sgbr...@comcast.net 
> C - 603 617 9116
> 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 
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Re: [PSES] Stability

[Bob Griffin]

Steve
If IEC61010 is insufficient in some way, You might also consider IEC62368-1(AV, 
ICT) or IEC60601-1 (Medical)

Both have stability requirements associated with equipment that is primarily 
moved on castors for basic stability and installation and additional safeguards 
for equipment and carts/stands that are moved during more routine or normal 
operation. I think they both also have specific requirements for castors that 
might be more applicable to address routine movement and thresholds. At least 
in IEC62368-1, the requirements vary by type of person doing the moving 
(ordinary, skilled or instructed persons).



> On Jul 24, 2023, at 12:15 PM, Douglas Nix 
> <0bb8ff993b10-dmarc-requ...@listserv.ieee.org> wrote:
> 
> Hi Steve,
> 
> IMO, EN 60204-1 is the wrong standard. You said that the cart is used in a 
> lab setting. You need to use a lab equipment standard, and for the EU EN 
> 61010-1 is the correct choice.
> 
> If not that, then you really need to add a bunch of additional machinery 
> related standards, which I also think is the wrong choice since the cart 
> doesn’t sound like it meets the definition of a machine.
> 
> --
> Doug Nix
> d...@mac.com
> (519) 729-5704
> 
> "Our greatest weakness lies in giving up. The most certain way to succeed is 
> always to try just one more time." - Thomas Edison
> 
> 
> 
>> On Jul 22, 2023, at 15:51, Steve Brody  wrote:
>> 
>> A client has a product which is a mobile cart intended for a laboratory 
>> setting in which it can be moved to whatever lab station it is needed at.  
>> It is on casters and when wheeled to the working location, leveling feet 
>> which are located in the center of the castor mount, are lowered and locked 
>> into position to keep the cart from moving and to ensure it is level.
>> 
>> The product will be evaluated to EN 60204-1, but there is no reference to 
>> stability in this standard.
>> 
>> First question is should EN 61010-1, 7.4, be used to evaluate stability, and 
>> if not then what?
>>  
>> Assuming yes, the first sentence of 7.4 says; 'Equipment and assemblies of 
>> equipment not secured to the building structure before operation should be 
>> physically stable.'
>>  
>> Second question is does this section apply to the cart only when in position 
>> for use, or also when being moved from location to location? 
>>  
>> Because when in use the cart is supported by [properly rated] feet, then the 
>> tests for castors should no longer apply?.
>> 
>> That is the third question.
>>  
>> Your thoughts and comments are requested and appreciated, as always. 
>>  
>> Thanks,
>>  
>> Steve Brody
>> sgbr...@comcast.net 
>> C - 603 617 9116
>> 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/
>> 
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>> unsubscribe) 
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> 
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[PSES] Order of attenuators

[doug emcesd.com]

Hi All,

Here is a puzzle. I have a signal source of average power less than 10 mW and I 
want to put three attenuators on the output, 20 dB, 6 dB and 3 dB.  All are two 
Watt attenuators. What order should I put them on to minimize the chance of 
burning some of them out? This is a situation I encounter during my circuit 
troubleshooting.

Doug
[https://lh4.googleusercontent.com/_HuR3Ky2TF_XhFHyxnYRmiq7nHQldnMsPNYFaLG6kb5T4y8MeCe-BDC_BscJtSFgszSSjssihHS-pjM3-jwNP8S0CwE-gN8fsRsPkojiAlmpBwb20vIVizS-siCUywW_jqrefbVr]

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Re: [PSES] Order of attenuators

[John Woodgate]

6, 3, 20. The calculations are left as an exercise for thereader. 😉

On 2023-07-24 20:14, doug emcesd.com wrote:


Hi All,

Here is a puzzle. I have a signal source of average power less than 10 
mW and I want to put three attenuators on the output, 20 dB, 6 dB and 
3 dB.  All are two Watt attenuators. What order should I put them on 
to minimize the chance of burning some of them out? This is a 
situation I encounter during my circuit troubleshooting.


Doug



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Re: [PSES] Woodgate's reply on residential Immunity field strength

[Brian Gregory]

 The reference for 20 V/m to EV chargers comes from UL 2231-2.  This is not a 
medical standard, but Annex A does call out the medical standard 60601-1-2 as a 
reference, as well as CENELEC 50204.  We can't figure out why;  cell phones 
produce less than half that, and our WiFi transmitter is probably 
representative, and is rated well under 1 W.  I could see a higher immunity 
standard as needed for commercial environments, say in a bank of 4-5 chargers. 
Following along in 61000-4-3, we agree with John that residential applications 
are clearly best matched to the definition for Class 2 environment, and the 
table in Clause 5 says the limits for Class 2 equipment is 3 V/m.  20 V/m does 
not show up in Clause 5 of 61000-4-3 for any class.   So, I've should to reach 
out to a UL standards group and find out if this is really necessary for 
residential applications.   Our local lab can't do more than 10, and an 
overseas affiliated lab is similarly limited.  I'd like to know were this 
requirement comes from.   This is more a question for EV Charging safety than a 
mainstream EMC question.  As a backup, I could request a comment to Ken's point 
is if they define the peak of the modulation as 20 V/m.  I don't know where 
these are defined. Thanks for all the detailed replies! Colorado Brian 
720-450-4933

-- Original Message --
From: John Woodgate 
To: Brian Gregory 
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100


61000-4-3 is a Basic Standard. It does not specify test levels but indicates 
possible test levels. You need to look in detail at Clause 5, but look at these 
words:
 Product committees shall select the appropriate test level for each frequency 
range needing to be tested as well as the frequency ranges.
The residential environment is usually designated Class 2 (see Annex E of the 
standard), which calls for 3 V/m.
==
 Best wishes John Woodgate OOO-Own Opinions Only
 www.woodjohn.uk
 Rayleigh, Essex UK
 
 I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi 
(340 - 245 BC)On 2023-07-21 17:44, Brian Gregory wrote: Hello colleagues,  We 
are building EV Chargers for residential markets (not just US) and one of the 
safety applicable standards is UL 2231-2.  It calls out  IEC 61000-4-3 for 
immunity testing parameters, which states a requirement for a field strength of 
20V/m.  Our EMC expert says typically testing is "done at 3 Vrms, which is 
standard for most products in residential environments."   He can only test up 
to 10V, and we're hearing the same from an overseas lab to whom our 
manufacturer refers.   Does FCC Part B have guidelines for field strength we 
can cite?   Can some offer this "DC guy" (aka, 60 Hz) a quick definition of 
what the 20V/m represents? I'm guessing 20 V/m is for higher density commercial 
applications, aka charging stations, so we probably need an exception for 
residential.   Thank you! Colorado Brian 
 720-450-4933This 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 
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Re: [PSES] Woodgate's reply on residential Immunity field strength

[Jim Bacher, WB8VSU]

Wi-Fi and cell phones are not the only transmitters near cars. There are 
police, fire and ham radio transceivers in cars. Some of which are on gain 
antennas and can be remotely accessed to transmit. Not to mention hand held 
transceivers that might walk by.


Jim, WB8VSU


On July 24, 2023 5:51:27 PM Brian Gregory  wrote:


The reference for 20 V/m to EV chargers comes from UL 2231-2.  This is not 
a medical standard, but Annex A does call out the medical standard 
60601-1-2 as a reference, as well as CENELEC 50204.  We can't figure out 
why;  cell phones produce less than half that, and our WiFi transmitter is 
probably representative, and is rated well under 1 W.  I could see a higher 
immunity standard as needed for commercial environments, say in a bank of 
4-5 chargers.


Following along in 61000-4-3, we agree with John that residential 
applications are clearly best matched to the definition for Class 2 
environment, and the table in Clause 5 says the limits for Class 2 
equipment is 3 V/m.  20 V/m does not show up in Clause 5 of 61000-4-3 for 
any class.


So, I've should to reach out to a UL standards group and find out if this 
is really necessary for residential applications.   Our local lab can't do 
more than 10, and an overseas affiliated lab is similarly limited.  I'd 
like to know were this requirement comes from.   This is more a question 
for EV Charging safety than a mainstream EMC question.


As a backup, I could request a comment to Ken's point is if they define the 
peak of the modulation as 20 V/m.  I don't know where these are defined.


Thanks for all the detailed replies!

Colorado Brian
720-450-4933

-- Original Message --
From: John Woodgate 
To: Brian Gregory 
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100



61000-4-3 is a Basic Standard. It does not specify test levels but 
indicates possible test levels. You need to look in detail at Clause 5, but 
look at these words:
Product committees shall select the appropriate test level for each 
frequency range needing to be tested as well as the frequency ranges.
The residential environment is usually designated Class 2 (see Annex E of 
the standard), which calls for 3 V/m.

==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi 
(340 - 245 BC)On 2023-07-21 17:44, Brian Gregory wrote:

Hello colleagues,

We are building EV Chargers for residential markets (not just US) and one 
of the safety applicable standards is UL 2231-2.  It calls out  IEC 
61000-4-3 for immunity testing parameters, which states a requirement for a 
field strength of 20V/m.  Our EMC expert says typically testing is "done at 
3 Vrms, which is standard for most products in residential environments."   
He can only test up to 10V, and we're hearing the same from an overseas lab 
to whom our manufacturer refers.


Does FCC Part B have guidelines for field strength we can cite?   Can some 
offer this "DC guy" (aka, 60 Hz) a quick definition of what the 20V/m 
represents?


I'm guessing 20 V/m is for higher density commercial applications, aka 
charging stations, so we probably need an exception for residential.


Thank you!

Colorado Brian
720-450-4933This 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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-

Re: [PSES] Woodgate's reply on residential Immunity field strength

[John Woodgate]

There are, but 20 V/m still is a very high value. One wouldn't expect a 
transmitter to be used in a car while it is on charge.


On 2023-07-24 22:57, Jim Bacher, WB8VSU wrote:
Wi-Fi and cell phones are not the only transmitters near cars. There 
are police, fire and ham radio transceivers in cars. Some of which are 
on gain antennas and can be remotely accessed to transmit. Not to 
mention hand held transceivers that might walk by.


Jim, WB8VSU


On July 24, 2023 5:51:27 PM Brian Gregory  
wrote:


The reference for 20 V/m to EV chargers comes from UL 2231-2.  This 
is not a medical standard, but Annex A does call out the medical 
standard 60601-1-2 as a reference, as well as CENELEC 50204.  We 
can't figure out why;  cell phones produce less than half that, and 
our WiFi transmitter is probably representative, and is rated well 
under 1 W.  I could see a higher immunity standard as needed for 
commercial environments, say in a bank of 4-5 chargers.
Following along in 61000-4-3, we agree with John that residential 
applications are clearly best matched to the definition for Class 2 
environment, and the table in Clause 5 says the limits for Class 2 
equipment is 3 V/m.  20 V/m does not show up in Clause 5 of 61000-4-3 
for any class.
So, I've should to reach out to a UL standards group and find out if 
this is really necessary for residential applications.   Our local 
lab can't do more than 10, and an overseas affiliated lab is 
similarly limited.  I'd like to know were this requirement comes 
from.   This is more a question for EV Charging safety than 
a mainstream EMC question.
As a backup, I could request a comment to Ken's point is if they 
define the peak of the modulation as 20 V/m.  I don't know where 
these are defined.

Thanks for all the detailed replies!
Colorado Brian
720-450-4933


-- Original Message --
From: John Woodgate 
To: Brian Gregory 
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100

61000-4-3 is a Basic Standard. It does not specify test levels but 
indicates possible test levels. You need to look in detail at Clause 
5, but look at these words:


/Product committees shall select the appropriate test level for each 
frequency range //needing to be tested as well as the frequency ranges./


The residential environment is usually designated Class 2 (see Annex 
E of the standard), which calls for 3 V/m.


==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. 
Xunzi (340 - 245 BC)

On 2023-07-21 17:44, Brian Gregory wrote:

 Hello colleagues,
We are building EV Chargers for residential markets (not just US)
and one of the safety applicable standards is UL 2231-2.  It
calls out  IEC 61000-4-3 for immunity testing parameters, which
states a requirement for a field strength of 20V/m.  Our EMC
expert says typically testing is "done at 3 Vrms, which is
standard for most products in residential environments."   He can
only test up to 10V, and we're hearing the same from an overseas
lab to whom our manufacturer refers.
Does FCC Part B have guidelines for field strength we can cite? 
 Can some offer this "DC guy" (aka, 60 Hz) a quick definition of
what the 20V/m represents?
I'm guessing 20 V/m is for higher density commercial
applications, aka charging stations, so we probably need an
exception for residential.
Thank you!
Colorado Brian
720-450-4933


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
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List rules: https://ewh.ieee.org/soc/pses/listrules.html

For help, send mail to the list administrators:
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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:

https://www.mail-archive.com/e

Re: [PSES] Woodgate's reply on residential Immunity field strength

[Ken Javor]

AM transmissions obviously have different amplitudes when modulated than when 
not.  Above 1 GHz, where transmissions are primarily digitally encoded 
(phase/frequency shift modulation techniques where the amplitude is constant), 
I don’t believe this is the case.  So it may be that above (for instance) 1 
GHz, the IEC formula of adding the modulation depth to the cw limit (i.e,, 10 
V/m limit modulated at 80% becomes 18 V/m peak of the modulation envelope) 
ought to look more like mil and aerospace practice where the limit is the limit.

 

Just to stir the pot, it isn’t obvious to me (with a largely mil and aerospace 
background) why the IEC took this approach.  Granted AM is AM, but why not 
simply specify a limit and say that the limit is measured as the peak of the 
modulation envelope?  Assuming that say 10 V/m cw is desired, the limit is then 
expressed as 18 V/m (or 20 V/m to use round numbers).

 

-- 

Ken Javor

(256) 650-5261

 

From: Brian Gregory 
Reply-To: Brian Gregory 
Date: Monday, July 24, 2023 at 4:49 PM
To: 
Subject: Re: [PSES] Woodgate's reply on residential Immunity field strength

 

 

The reference for 20 V/m to EV chargers comes from UL 2231-2.  This is not a 
medical standard, but Annex A does call out the medical standard 60601-1-2 as a 
reference, as well as CENELEC 50204.  We can't figure out why;  cell phones 
produce less than half that, and our WiFi transmitter is probably 
representative, and is rated well under 1 W.  I could see a higher immunity 
standard as needed for commercial environments, say in a bank of 4-5 chargers.

 

Following along in 61000-4-3, we agree with John that residential applications 
are clearly best matched to the definition for Class 2 environment, and the 
table in Clause 5 says the limits for Class 2 equipment is 3 V/m.  20 V/m does 
not show up in Clause 5 of 61000-4-3 for any class.  

 

So, I've should to reach out to a UL standards group and find out if this is 
really necessary for residential applications.   Our local lab can't do more 
than 10, and an overseas affiliated lab is similarly limited.  I'd like to know 
were this requirement comes from.   This is more a question for EV Charging 
safety than a mainstream EMC question. 

 

As a backup, I could request a comment to Ken's point is if they define the 
peak of the modulation as 20 V/m.  I don't know where these are defined.

 

Thanks for all the detailed replies!

 

Colorado Brian 
720-450-4933



-- Original Message --
From: John Woodgate 
To: Brian Gregory 
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100

61000-4-3 is a Basic Standard. It does not specify test levels but indicates 
possible test levels. You need to look in detail at Clause 5, but look at these 
words:

 Product committees shall select the appropriate test level for each frequency 
range needing to be tested as well as the frequency ranges.

The residential environment is usually designated Class 2 (see Annex E of the 
standard), which calls for 3 V/m.

==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi (340 
- 245 BC)

On 2023-07-21 17:44, Brian Gregory wrote:

 Hello colleagues, 

 

We are building EV Chargers for residential markets (not just US) and one of 
the safety applicable standards is UL 2231-2.  It calls out  IEC 61000-4-3 for 
immunity testing parameters, which states a requirement for a field strength of 
20V/m.  Our EMC expert says typically testing is "done at 3 Vrms, which is 
standard for most products in residential environments."   He can only test up 
to 10V, and we're hearing the same from an overseas lab to whom our 
manufacturer refers.  

 

Does FCC Part B have guidelines for field strength we can cite?   Can some 
offer this "DC guy" (aka, 60 Hz) a quick definition of what the 20V/m 
represents?

 

I'm guessing 20 V/m is for higher density commercial applications, aka charging 
stations, so we probably need an exception for residential.  

 

Thank you!

 

Colorado Brian 
720-450-4933

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/ 
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List rules: https://ewh.ieee.org/soc/pses/listrules.html

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Re: [PSES] Woodgate's reply on residential Immunity field strength

[Jim Bacher, WB8VSU]

John, I have transmitter that transmits on a VHF Frequency about 2 minutes 
after I shut the car off. A number of setups allow a person to use a hand 
held device to access a higher powered transceiver that is in the car. It's 
fairly common setup for highway patrol vehicles, due to distance from the 
control points.


Jim



On July 24, 2023 6:04:13 PM John Woodgate  wrote:
There are, but 20 V/m still is a very high value. One wouldn't expect a 
transmitter to be used in a car while it is on charge.

On 2023-07-24 22:57, Jim Bacher, WB8VSU wrote:
Wi-Fi and cell phones are not the only transmitters near cars. There are 
police, fire and ham radio transceivers in cars. Some of which are on gain 
antennas and can be remotely accessed to transmit. Not to mention hand held 
transceivers that might walk by.


Jim, WB8VSU


On July 24, 2023 5:51:27 PM Brian Gregory  wrote:


The reference for 20 V/m to EV chargers comes from UL 2231-2.  This is not 
a medical standard, but Annex A does call out the medical standard 
60601-1-2 as a reference, as well as CENELEC 50204.  We can't figure out 
why;  cell phones produce less than half that, and our WiFi transmitter is 
probably representative, and is rated well under 1 W.  I could see a higher 
immunity standard as needed for commercial environments, say in a bank of 
4-5 chargers.


Following along in 61000-4-3, we agree with John that residential 
applications are clearly best matched to the definition for Class 2 
environment, and the table in Clause 5 says the limits for Class 2 
equipment is 3 V/m.  20 V/m does not show up in Clause 5 of 61000-4-3 for 
any class.


So, I've should to reach out to a UL standards group and find out if this 
is really necessary for residential applications.   Our local lab can't do 
more than 10, and an overseas affiliated lab is similarly limited.  I'd 
like to know were this requirement comes from.   This is more a question 
for EV Charging safety than a mainstream EMC question.


As a backup, I could request a comment to Ken's point is if they define the 
peak of the modulation as 20 V/m.  I don't know where these are defined.


Thanks for all the detailed replies!

Colorado Brian
720-450-4933

-- Original Message --
From: John Woodgate 
To: Brian Gregory 
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100

61000-4-3 is a Basic Standard. It does not specify test levels but 
indicates possible test levels. You need to look in detail at Clause 5, but 
look at these words:
Product committees shall select the appropriate test level for each 
frequency range needing to be tested as well as the frequency ranges.
The residential environment is usually designated Class 2 (see Annex E of 
the standard), which calls for 3 V/m.

==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi 
(340 - 245 BC)On 2023-07-21 17:44, Brian Gregory wrote:

Hello colleagues,

We are building EV Chargers for residential markets (not just US) and one 
of the safety applicable standards is UL 2231-2.  It calls out  IEC 
61000-4-3 for immunity testing parameters, which states a requirement for a 
field strength of 20V/m.  Our EMC expert says typically testing is "done at 
3 Vrms, which is standard for most products in residential environments."   
He can only test up to 10V, and we're hearing the same from an overseas lab 
to whom our manufacturer refers.


Does FCC Part B have guidelines for field strength we can cite?   Can some 
offer this "DC guy" (aka, 60 Hz) a quick definition of what the 20V/m 
represents?


I'm guessing 20 V/m is for higher density commercial applications, aka 
charging stations, so we probably need an exception for residential.


Thank you!

Colorado Brian
720-450-4933This 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, send mail to the list administrators:
Mike Sherman at: msherma...@comcast.net
Rick Linford at: linf...@ieee.org
For policy questions, send mail to:
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To unsubscribe from the EMC-PSTC list, click the following link: 
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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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Re: [PSES] Woodgate's reply on residential Immunity field strength

[John Woodgate]

While the vehicle is on charge or vey near a charger?

On 2023-07-24 23:12, Jim Bacher, WB8VSU wrote:
John, I have transmitter that transmits on a VHF Frequency about 2 
minutes after I shut the car off. A number of setups allow a person to 
use a hand held device to access a higher powered transceiver that is 
in the car. It's fairly common setup for highway patrol vehicles, due 
to distance from the control points.


Jim



On July 24, 2023 6:04:13 PM John Woodgate  wrote:

There are, but 20 V/m still is a very high value. One wouldn't expect 
a transmitter to be used in a car while it is on charge.


On 2023-07-24 22:57, Jim Bacher, WB8VSU wrote:
Wi-Fi and cell phones are not the only transmitters near cars. There 
are police, fire and ham radio transceivers in cars. Some of which 
are on gain antennas and can be remotely accessed to transmit. Not 
to mention hand held transceivers that might walk by.


Jim, WB8VSU


On July 24, 2023 5:51:27 PM Brian Gregory 
 wrote:


The reference for 20 V/m to EV chargers comes from UL 2231-2.  This 
is not a medical standard, but Annex A does call out the medical 
standard 60601-1-2 as a reference, as well as CENELEC 50204.  We 
can't figure out why;  cell phones produce less than half that, and 
our WiFi transmitter is probably representative, and is rated well 
under 1 W.  I could see a higher immunity standard as needed for 
commercial environments, say in a bank of 4-5 chargers.
Following along in 61000-4-3, we agree with John that residential 
applications are clearly best matched to the definition for Class 2 
environment, and the table in Clause 5 says the limits for Class 2 
equipment is 3 V/m. 20 V/m does not show up in Clause 5 
of 61000-4-3 for any class.
So, I've should to reach out to a UL standards group and find out 
if this is really necessary for residential applications.   Our 
local lab can't do more than 10, and an overseas affiliated lab is 
similarly limited.  I'd like to know were this requirement comes 
from.  This is more a question for EV Charging safety than 
a mainstream EMC question.
As a backup, I could request a comment to Ken's point is if they 
define the peak of the modulation as 20 V/m.  I don't know where 
these are defined.

Thanks for all the detailed replies!
Colorado Brian
720-450-4933


-- Original Message --
From: John Woodgate 
To: Brian Gregory 
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100

61000-4-3 is a Basic Standard. It does not specify test levels but 
indicates possible test levels. You need to look in detail at 
Clause 5, but look at these words:


/Product committees shall select the appropriate test level for 
each frequency range //needing to be tested as well as the 
frequency ranges./


The residential environment is usually designated Class 2 (see 
Annex E of the standard), which calls for 3 V/m.


==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I 
understand. Xunzi (340 - 245 BC)

On 2023-07-21 17:44, Brian Gregory wrote:

 Hello colleagues,
We are building EV Chargers for residential markets (not just
US) and one of the safety applicable standards is UL
2231-2.  It calls out  IEC 61000-4-3 for immunity testing
parameters, which states a requirement for a field strength of
20V/m.  Our EMC expert says typically testing is "done at 3
Vrms, which is standard for most products in residential
environments."   He can only test up to 10V, and we're hearing
the same from an overseas lab to whom our manufacturer refers.
Does FCC Part B have guidelines for field strength we can cite?
 Can some offer this "DC guy" (aka, 60 Hz) a quick definition
of what the 20V/m represents?
I'm guessing 20 V/m is for higher density commercial
applications, aka charging stations, so we probably need an
exception for residential.
Thank you!
Colorado Brian
720-450-4933


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Re: [PSES] Woodgate's reply on residential Immunity field strength

[Ken Javor]

Piling on, while one may compute very high field intensities from say a mobile 
phone or other such microwave handheld transmitter, these field intensities 
will not illuminate a 1.5 m square area at such levels.  If such levels are in 
fact justified, it might make sense to reduce the required uniform field area, 
thereby allowing the use of higher gain antennas, and lower power amplifier 
requirements at the higher frequencies where such power becomes (even more) 
expensive.

 

-- 

Ken Javor

(256) 650-5261

 

From: John Woodgate 
Reply-To: John Woodgate 
Date: Monday, July 24, 2023 at 5:03 PM
To: 
Subject: Re: [PSES] Woodgate's reply on residential Immunity field strength

 

There are, but 20 V/m still is a very high value. One wouldn't expect a 
transmitter to be used in a car while it is on charge.

On 2023-07-24 22:57, Jim Bacher, WB8VSU wrote:

Wi-Fi and cell phones are not the only transmitters near cars. There are 
police, fire and ham radio transceivers in cars. Some of which are on gain 
antennas and can be remotely accessed to transmit. Not to mention hand held 
transceivers that might walk by. 

 

Jim, WB8VSU 

 

 

On July 24, 2023 5:51:27 PM Brian Gregory  wrote:

 

The reference for 20 V/m to EV chargers comes from UL 2231-2.  This is not a 
medical standard, but Annex A does call out the medical standard 60601-1-2 as a 
reference, as well as CENELEC 50204.  We can't figure out why;  cell phones 
produce less than half that, and our WiFi transmitter is probably 
representative, and is rated well under 1 W.  I could see a higher immunity 
standard as needed for commercial environments, say in a bank of 4-5 chargers.

 

Following along in 61000-4-3, we agree with John that residential applications 
are clearly best matched to the definition for Class 2 environment, and the 
table in Clause 5 says the limits for Class 2 equipment is 3 V/m.  20 V/m does 
not show up in Clause 5 of 61000-4-3 for any class.  

 

So, I've should to reach out to a UL standards group and find out if this is 
really necessary for residential applications.   Our local lab can't do more 
than 10, and an overseas affiliated lab is similarly limited.  I'd like to know 
were this requirement comes from.   This is more a question for EV Charging 
safety than a mainstream EMC question. 

 

As a backup, I could request a comment to Ken's point is if they define the 
peak of the modulation as 20 V/m.  I don't know where these are defined.

 

Thanks for all the detailed replies!

 

Colorado Brian 
720-450-4933



-- Original Message --
From: John Woodgate 
To: Brian Gregory 
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100

61000-4-3 is a Basic Standard. It does not specify test levels but indicates 
possible test levels. You need to look in detail at Clause 5, but look at these 
words:

 Product committees shall select the appropriate test level for each frequency 
range needing to be tested as well as the frequency ranges.

The residential environment is usually designated Class 2 (see Annex E of the 
standard), which calls for 3 V/m.

==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi (340 
- 245 BC)

On 2023-07-21 17:44, Brian Gregory wrote:

 Hello colleagues, 

 

We are building EV Chargers for residential markets (not just US) and one of 
the safety applicable standards is UL 2231-2.  It calls out  IEC 61000-4-3 for 
immunity testing parameters, which states a requirement for a field strength of 
20V/m.  Our EMC expert says typically testing is "done at 3 Vrms, which is 
standard for most products in residential environments."   He can only test up 
to 10V, and we're hearing the same from an overseas lab to whom our 
manufacturer refers.  

 

Does FCC Part B have guidelines for field strength we can cite?   Can some 
offer this "DC guy" (aka, 60 Hz) a quick definition of what the 20V/m 
represents?

 

I'm guessing 20 V/m is for higher density commercial applications, aka charging 
stations, so we probably need an exception for residential.  

 

Thank you!

 

Colorado Brian 
720-450-4933

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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To unsubscribe 

Re: [PSES] Order of attenuators

[doug emcesd.com]

Hi All,

It turns out the signal generator has an average output of only mW, but a peak 
power of 5000W or so. This is a small battery powered hand-held EFT like pulse 
generator, from Fischer Custom Communications, that I use for circuit 
troubleshooting. It will deliver thousands of Watts of peak power into 50 Ohms! 
The pulse is somewhat shortened from a standard EFT pulse to allow the use of 2 
Watt attenuators. However, to minimize the stress on the attenuators they 
should be positioned as follows from the output of the generator: 3, 6, 20 dB. 
That way the 20 dB attenuator is more likely to survive and can even be a ½ 
Watt rating. If placed first, It will take most of the power and may not 
survive.

EFT and especially ESD have extreme peak to average ratios and for signals like 
this, the lowest attenuation attenuators should be used first.

Separately, I have a few guidelines for ESD or EFT debugging:

  *   Generally, it is not very efficient to debug these problems on the 
official test sites. If this is done, in my experience, the solution will take 
a lot longer, may not be well understood, and likely cost more (because it is 
not the best solution).
  *   I usually do not consult system documentation in the early stages of 
debugging, an inefficient use of time.
  *   I inject voltage via mutual inductance or current through 1-2 pF of 
capacitance, known levels of noise into the circuit (I know how much signal the 
circuit is stressed with even though I may not yet know the circuit details). 
The injection, for mutual inductance, must have a short range, ¼ inch or less.
  *   I find the part of the circuit causing the problem and then consult the 
documentation to finalize my fix. In one case it was a 20 pF cap to circuit 
ground. At that point, I had no idea of the circuit and why the fix worked 
until consulting the documentation. It took me 5 minutes to localize the 
problem to one single node in the circuit before consulting the documentation. 
That is after another consultant could not find the problem after 4 days of 
work using the conventional engineering methods we all know.
  *   ESD/EFT like, but low level and no circuit contact, noise with close in 
injection is a very powerful technique for debugging a circuit that has an 
ESD/EFT problem. I have been fine tuning this procedure for about 40 years now.

Doug
[https://lh4.googleusercontent.com/_HuR3Ky2TF_XhFHyxnYRmiq7nHQldnMsPNYFaLG6kb5T4y8MeCe-BDC_BscJtSFgszSSjssihHS-pjM3-jwNP8S0CwE-gN8fsRsPkojiAlmpBwb20vIVizS-siCUywW_jqrefbVr]
From: Richard Nute 
Sent: Monday, July 24, 2023 13:51
To: doug emcesd.com 
Subject: RE: [PSES] Order of attenuators



Hi Doug:

Since the source is 10 mW, and the attenuators are 2 W (I assume resistive, 
50-ohm, see attached schematic), then any attenuator should be able to 
dissipate the 10 mW of the source.

However, to minimize power dissipation in each attenuator, they should be 
arranged 3 dB, 6 dB, and 20 dB.

Best regards,
Rich

From: doug emcesd.com mailto:d...@emcesd.com>>
Sent: Monday, July 24, 2023 12:15 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Order of attenuators

Hi All,

Here is a puzzle. I have a signal source of average power less than 10 mW and I 
want to put three attenuators on the output, 20 dB, 6 dB and 3 dB.  All are two 
Watt attenuators. What order should I put them on to minimize the chance of 
burning some of them out? This is a situation I encounter during my circuit 
troubleshooting.

Doug
[https://lh4.googleusercontent.com/_HuR3Ky2TF_XhFHyxnYRmiq7nHQldnMsPNYFaLG6kb5T4y8MeCe-BDC_BscJtSFgszSSjssihHS-pjM3-jwNP8S0CwE-gN8fsRsPkojiAlmpBwb20vIVizS-siCUywW_jqrefbVr]

-

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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Re: [PSES] Woodgate's reply on residential Immunity field strength

[Jim Bacher, WB8VSU]

Yes. The standards need to allow for possibilities.

I have about a 3 dB gain antenna that is about a meter away from the 
charger port. It transmits about 15 watts at 144.39 MHz to send out an APRS 
position packet.  I recently bought a PHEV, although my 2 minute timer is 
not yet installed, but it will be.



The catch is I am not the only one doing this and who knows what the others 
have for antenna to charger spacing, etc. Although most of the Hams likely 
do not have EVs at the moment, but some do.



Bob Bruninga WB4APR, who was the ham behind the creation of APRS drove a 
Prius. He passed away a few years ago. Info on APRS is at: http://www.aprs.org/



I could easily be on a handheld device and talking with someone when 
plugging or unplugging the charger cable. I had a issue many years ago 
where the hand held transceiver exposed a device to 45 V/m (someone else 
did the calculations).



I had friends that in the late 1970s were remotely controlling transceivers 
in their cars. Cars at that time obviously were not EVs. They would use it 
at work. They owned the businesses, so they could play if they wanted to. 
The thing is others could be doing the same today, while the car is 
charging. Plus like I mentioned highway patrol cars use the same setup. If 
they start using EVs, they also would be a similar issue.



Plus what if a car with a high powered transceiver parks near by?

Jim

On July 24, 2023 6:17:45 PM John Woodgate  wrote:

While the vehicle is on charge or vey near a charger?
On 2023-07-24 23:12, Jim Bacher, WB8VSU wrote:
John, I have transmitter that transmits on a VHF Frequency about 2 minutes 
after I shut the car off. A number of setups allow a person to use a hand 
held device to access a higher powered transceiver that is in the car. It's 
fairly common setup for highway patrol vehicles, due to distance from the 
control points.


Jim



On July 24, 2023 6:04:13 PM John Woodgate  wrote:
There are, but 20 V/m still is a very high value. One wouldn't expect a 
transmitter to be used in a car while it is on charge.

On 2023-07-24 22:57, Jim Bacher, WB8VSU wrote:
Wi-Fi and cell phones are not the only transmitters near cars. There are 
police, fire and ham radio transceivers in cars. Some of which are on gain 
antennas and can be remotely accessed to transmit. Not to mention hand held 
transceivers that might walk by.


Jim, WB8VSU


On July 24, 2023 5:51:27 PM Brian Gregory  wrote:


The reference for 20 V/m to EV chargers comes from UL 2231-2.  This is not 
a medical standard, but Annex A does call out the medical standard 
60601-1-2 as a reference, as well as CENELEC 50204.  We can't figure out 
why;  cell phones produce less than half that, and our WiFi transmitter is 
probably representative, and is rated well under 1 W.  I could see a higher 
immunity standard as needed for commercial environments, say in a bank of 
4-5 chargers.


Following along in 61000-4-3, we agree with John that residential 
applications are clearly best matched to the definition for Class 2 
environment, and the table in Clause 5 says the limits for Class 2 
equipment is 3 V/m.  20 V/m does not show up in Clause 5 of 61000-4-3 for 
any class.


So, I've should to reach out to a UL standards group and find out if this 
is really necessary for residential applications.   Our local lab can't do 
more than 10, and an overseas affiliated lab is similarly limited.  I'd 
like to know were this requirement comes from.   This is more a question 
for EV Charging safety than a mainstream EMC question.


As a backup, I could request a comment to Ken's point is if they define the 
peak of the modulation as 20 V/m.  I don't know where these are defined.


Thanks for all the detailed replies!

Colorado Brian
720-450-4933

-- Original Message --
From: John Woodgate 
To: Brian Gregory 
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100

61000-4-3 is a Basic Standard. It does not specify test levels but 
indicates possible test levels. You need to look in detail at Clause 5, but 
look at these words:
Product committees shall select the appropriate test level for each 
frequency range needing to be tested as well as the frequency ranges.
The residential environment is usually designated Class 2 (see Annex E of 
the standard), which calls for 3 V/m.

==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk
Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi 
(340 - 245 BC)On 2023-07-21 17:44, Brian Gregory wrote:

Hello colleagues,

We are building EV Chargers for residential markets (not just US) and one 
of the safety applicable standards is UL 2231-2.  It calls out  IEC 
61000-4-3 for immunity testing parameters, which states a requirement for a 
field strength of 20V/m.  Our EMC expert says typically testing is 

Re: [PSES] Woodgate's reply on residential Immunity field strength

[James Pawson (U3C)]

Hi Brian,

 

In IEC 61000-4-3 the level is defined as the unmodulated rms field strength.
The modulation (1kHz 80% AM) is applied symmetrically around that level.
>From memory this means that the peak is 5.1dB higher than the level.

 

The opposite is true in ISO 11452-2 for automotive where the level is the
maximum peak and the modulation (AM, same as above) is modulated down from
this peak.

 

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.

 

 

 

 

From: Brian Gregory  
Sent: Monday, July 24, 2023 10:49 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Woodgate's reply on residential Immunity field strength

 

 

The reference for 20 V/m to EV chargers comes from UL 2231-2.  This is not a
medical standard, but Annex A does call out the medical standard 60601-1-2
as a reference, as well as CENELEC 50204.  We can't figure out why;  cell
phones produce less than half that, and our WiFi transmitter is probably
representative, and is rated well under 1 W.  I could see a higher immunity
standard as needed for commercial environments, say in a bank of 4-5
chargers.

 

Following along in 61000-4-3, we agree with John that residential
applications are clearly best matched to the definition for Class 2
environment, and the table in Clause 5 says the limits for Class 2 equipment
is 3 V/m.  20 V/m does not show up in Clause 5 of 61000-4-3 for any class.  

 

So, I've should to reach out to a UL standards group and find out if this is
really necessary for residential applications.   Our local lab can't do more
than 10, and an overseas affiliated lab is similarly limited.  I'd like to
know were this requirement comes from.   This is more a question for EV
Charging safety than a mainstream EMC question. 

 

As a backup, I could request a comment to Ken's point is if they define the
peak of the modulation as 20 V/m.  I don't know where these are defined.

 

Thanks for all the detailed replies!

 

Colorado Brian 
720-450-4933



-- Original Message --
From: John Woodgate mailto:j...@woodjohn.uk> >
To: Brian Gregory mailto:brian_greg...@netzero.net> >
Subject: Re: [PSES] Immunity test field strength, residential setting
Date: Fri, 21 Jul 2023 18:05:59 +0100

61000-4-3 is a Basic Standard. It does not specify test levels but indicates
possible test levels. You need to look in detail at Clause 5, but look at
these words:

 Product committees shall select the appropriate test level for each
frequency range needing to be tested as well as the frequency ranges.

The residential environment is usually designated Class 2 (see Annex E of
the standard), which calls for 3 V/m.


==
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk  
Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi
(340 - 245 BC)

On 2023-07-21 17:44, Brian Gregory wrote:

 Hello colleagues, 

 

We are building EV Chargers for residential markets (not just US) and one of
the safety applicable standards is UL 2231-2.  It calls out  IEC 61000-4-3
for immunity testing parameters, which states a requirement for a field
strength of 20V/m.  Our EMC expert says typically testing is "done at 3
Vrms, which is standard for most products in residential environments."   He
can only test up to 10V, and we're hearing the same from an overseas lab to
whom our manufacturer refers.  

 

Does FCC Part B have guidelines for field strength we can cite?   Can some
offer this "DC guy" (aka, 60 Hz) a quick definition of what the 20V/m
represents?

 

I'm guessing 20 V/m is for higher density commercial applications, aka
charging stations, so we probably need an exception for residential.  

 

Thank you!

 

Colorado Brian 
720-450-4933

  _  

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
mailto:emc-p...@ieee.org> > 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.o