Re: [PSES] Safety: 60335-1 conflicting clauses question - earthing (or not) of handles

[T.Sato]

On Wed, 5 Apr 2023 11:23:03 +0100,
  "James Pawson (U3C)"  wrote:

> In running through some safety checks on a customer's product I've come
> across what appears to be a conflict between two clauses. This resulted in
> some head scratching! I'm sure it is my misunderstanding or misreading, but
> I could do with some pointers in how to unpick this.
...
> 22.35 For constructions other than those of class III, handles, levers and
> knobs that are held or actuated in normal use shall not become live in the
> event of a failure of basic insulation. If these handles, levers and knobs
> are of metal and if their shafts or fixings are likely to become live in the
> event of a failure of basic insulation, they shall be adequately covered by
> insulating material or their accessible parts shall be separated from their
> shafts or fixings by supplementary insulation.
> 
> For stationary appliances and cordless appliances, this requirement does not
> apply to handles, levers and knobs, other than those of electrical
> components, provided that they are reliably connected to an earthing
> terminal or earthing contact or separated from live parts by earthed metal.
...
> 22.36 For appliances other than those of class III, handles which are
> continuously held in the hand in normal use shall be constructed so that
> when gripped in normal use, the operator's hand is not likely to touch metal
> parts unless they are separated from live parts by double insulation or
> reinforced insulation

I don't know of the reason of the differences, but it appears clause
22.35 (including the last paragraph "For stationary appliances...")
is for constructions, and clause 22.36 is for entier appliances.

Regards,
Tom


On Wed, 5 Apr 2023 11:23:03 +0100,
  "James Pawson (U3C)"  wrote:

> Hello experts,
> 
> In running through some safety checks on a customer's product I've come
> across what appears to be a conflict between two clauses. This resulted in
> some head scratching! I'm sure it is my misunderstanding or misreading, but
> I could do with some pointers in how to unpick this.
> 
> Context
> 
> * Standard is IEC EN 60335-1:2012 (+amendments)
> * Context is an exercise machine (the appliance)
> * Supply is AC mains Class I
> * Appliance has metal handles that are held during normal use. These
> are connected through bearings to the metal frame but are not "reliably
> earthed" (no explicit wired connection)
> 
> Earthing of metal parts is acceptable
> 
> 22.35 For constructions other than those of class III, handles, levers and
> knobs that are held or actuated in normal use shall not become live in the
> event of a failure of basic insulation. If these handles, levers and knobs
> are of metal and if their shafts or fixings are likely to become live in the
> event of a failure of basic insulation, they shall be adequately covered by
> insulating material or their accessible parts shall be separated from their
> shafts or fixings by supplementary insulation.
> 
> For stationary appliances and cordless appliances, this requirement does not
> apply to handles, levers and knobs, other than those of electrical
> components, provided that they are reliably connected to an earthing
> terminal or earthing contact or separated from live parts by earthed metal.
> 
> * Class I appliance, with metal handles held during use so this
> requirement is applicable
> * Handles are not reliably earthed so we are advising manufacturer to
> make an explicit bond to PE
> * With Basic insulation and Earthing we have our two safeguards
> between live and user = reduced risk of shock
> * No complaints with this clause
> 
> Earthing of metal parts is not accpetable
> 
> Then the next clause seems to contradict this:
> 
> 22.36 For appliances other than those of class III, handles which are
> continuously held in the hand in normal use shall be constructed so that
> when gripped in normal use, the operator's hand is not likely to touch metal
> parts unless they are separated from live parts by double insulation or
> reinforced insulation
> 
> * This clause appears to not allow for earthing of the metal handles
> * Instead, only rouble or reinforced insulation are acceptable
> * Thoughts / speculation:
> 
> o   Would this clause make more sense if it read "For appliances other than
> those of class I."? i.e. unearthed
> 
> o   Talks about "appliances" (whole product) rather than "constructions"
> (parts of appliance)
> 
> Conclusion
> 
> I'm happy that the approach of reliably earthing the metal handles will
> reduce the electric shock risk in the context of the equipment, this
> approach being consistent with other safety standards I know like 62368-1
> and 61010-1. I just can't rationalise this with clause 22.36. As I say, I'm
> sure I've misread or misunderstood something so any help would be greatly
> appreciated.
> 
> Otherwise, if anyone has a link to an explanatory document or contact for
> someone who could 

Re: [PSES] Question for FCC Part 18 RE test?

[T.Sato]

On Thu, 6 Apr 2023 11:32:20 +0900,
  Youngsik Kim  wrote:

> According to FCC part 18.305 FIELD STRENGTH LIMITS, a test article of Any
> type unless otherwise specified has a measurement distance of 300 meters,
> but I want to measure it at a distance of 3 meters because I need to
> measure it in a chamber.
> In this case, what is the limit at 3 meters?
> 
> If we use Any non-ISM frequency, the measurement distance is 300 meters and
> the limit value is 15 uV/m, We have a limit of 63.5 dBuV/m when measuring
> at 3 meters.
> However, other laboratories apply a limit of 103.5 dBuV/m.
> Depending on the RF power of the test device, can I use a 40 log instead of
> a 20 log conversion?
> Is the conversion different depending on the power of the test device?

See note 2 in the section, which says:

  Testing for compliance with these limits may be made at closer
  distances, provided a sufficient number of measurements are taken to
  plot the radiation pattern, to determine the major lobes of radiation,
  and to determine the expected field strength level at 30, 300, or 1600
  meters.

  Alternatively, if measurements are made at only one closer fixed
  distance, then the permissible field strength limits shall be adjusted
  using 1/d as an attenuation factor.

With the former method above, attenuation factor larger than -20 dB/decade
may be used if measurements at closer distances justified that.

Regards,
Tom

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Re: [PSES] Question for FCC Part 18 RE test?

[Ken Javor]

Not an expert on that standard, but technically speaking.

If indeed both 300 meter and 3 meters are both in the far field of the
transmitting antenna, then the scaling is as 20 log (distance ratio). That
would yield a 40 dB relaxation, so your first answer is correct.

I cannot think of a case where the scale factor is 40 log (distance ratio)
over such a large ratio.

In order to provide a more useful answer, the transmit frequency and antenna
physical size and gain and type would be useful.

Ken Javor
Phone: (256) 650-5261



From: Youngsik Kim 
Reply-To: Youngsik Kim 
Date: Thu, 6 Apr 2023 11:32:20 +0900
To: 
Subject: [PSES] Question for FCC Part 18 RE test?

Hi Experts

According to FCC part 18.305 FIELD STRENGTH LIMITS, a test article of Any
type unless otherwise specified has a measurement distance of 300 meters,
but I want to measure it at a distance of 3 meters because I need to measure
it in a chamber.
In this case, what is the limit at 3 meters?

If we use Any non-ISM frequency, the measurement distance is 300 meters and
the limit value is 15 uV/m, We have a limit of 63.5 dBuV/m when measuring at
3 meters.
However, other laboratories apply a limit of 103.5 dBuV/m.
Depending on the RF power of the test device, can I use a 40 log instead of
a 20 log conversion?
Is the conversion different depending on the power of the test device?

Translated with www.DeepL.com/Translator 
(free version)

Best Regards



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[PSES] Question for FCC Part 18 RE test?

[Youngsik Kim]

Hi Experts

According to FCC part 18.305 FIELD STRENGTH LIMITS, a test article of Any
type unless otherwise specified has a measurement distance of 300 meters,
but I want to measure it at a distance of 3 meters because I need to
measure it in a chamber.
In this case, what is the limit at 3 meters?

If we use Any non-ISM frequency, the measurement distance is 300 meters and
the limit value is 15 uV/m, We have a limit of 63.5 dBuV/m when measuring
at 3 meters.
However, other laboratories apply a limit of 103.5 dBuV/m.
Depending on the RF power of the test device, can I use a 40 log instead of
a 20 log conversion?
Is the conversion different depending on the power of the test device?

Translated with www.DeepL.com/Translator (free version)

Best Regards

-

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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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:
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 
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Re: [PSES] Safety: 60335-1 conflicting clauses question - earthing (or not) of handles

[Scott Aldous]

I'm not an expert in that standard, but at first glance it looks to me like
it makes a distinction between handles that are held or actuated in normal
use vs handles that are *continuously* held in the hand in normal use.
Similar to distinction made for surface temp limits in standards like 60950.

On Wed, Apr 5, 2023 at 6:52 AM Ken Javor 
wrote:

> I may be missing something but the way I read it they provide you with two
> different approaches to reducing the hazard of electric shock. One is
> protective earth grounding, and the other is double insulation, or double
> electrically isolated. These are mutually exclusive, being two different
> approaches to achieving the same goal.
>
> Ken Javor
> Phone: (256) 650-5261
>
>
> --
> *From: *"Grasso, Charles" 
> *Reply-To: *"Grasso, Charles" 
> *Date: *Wed, 5 Apr 2023 07:41:02 -0600
> *To: *
> *Subject: *Re: [PSES] Safety: 60335-1 conflicting clauses question -
> earthing (or not) of handles
>
> How exactly does one measure "likely" as in likely to touch? Is it a %age?
> Of course my question is tongue in cheek...
>
> On Wed, Apr 5, 2023, 4:23 AM James Pawson (U3C) <
> ja...@unit3compliance.co.uk> wrote:
>
>
> * This message originated outside of DISH and was sent by:
> ja...@unit3compliance.co.uk  *
> --
> Hello experts,
>
> In running through some safety checks on a customer’s product I’ve come
> across what appears to be a conflict between two clauses. This resulted in
> some head scratching! I’m sure it is my misunderstanding or misreading, but
> I could do with some pointers in how to unpick this.
>
>
> *Context *
>
>- Standard is IEC EN 60335-1:2012 (+amendments)
>- Context is an exercise machine (the appliance)
>- Supply is AC mains Class I
>- Appliance has metal handles that are held during normal use. These
>are connected through bearings to the metal frame but are not “reliably
>earthed” (no explicit wired connection)
>
>
>
> *Earthing of metal parts is acceptable *
>
>
> *22.35 For constructions other than those of class III, handles, levers
> and knobs that are held or actuated in normal use shall not become live in
> the event of a failure of basic insulation. If these handles, levers and
> knobs are of metal and if their shafts or fixings are likely to become live
> in the event of a failure of basic insulation, they shall be adequately
> covered by insulating material or their accessible parts shall be separated
> from their shafts or fixings by supplementary insulation.   For stationary
> appliances and cordless appliances, this requirement does not apply to
> handles, levers and knobs, other than those of electrical components,
> provided that they are reliably connected to an earthing terminal or
> earthing contact or separated from live parts by earthed metal. *
>
>- Class I appliance, with metal handles held during use so this
>requirement is applicable
>- Handles are not reliably earthed so we are advising manufacturer to
>make an explicit bond to PE
>- With Basic insulation and Earthing we have our two safeguards
>between live and user = reduced risk of shock
>- No complaints with this clause
>
>
>
> *Earthing of metal parts is not accpetable *Then the next clause seems to
> contradict this:
>
>
> *22.36 For appliances other than those of class III, handles which are
> continuously held in the hand in normal use shall be constructed so that
> when gripped in normal use, the operator's hand is not likely to touch
> metal parts unless they are separated from live parts by double insulation
> or reinforced insulation *
>
>- This clause appears to *not* allow for earthing of the metal handles
>- Instead, only rouble or reinforced insulation are acceptable
>- Thoughts / speculation:
>
> o   Would this clause make more sense if it read “For appliances other
> than those of class I…”? i.e. unearthed
>
> o   Talks about “appliances” (whole product) rather than “constructions”
> (parts of appliance)
>
>
>
> *Conclusion *I’m happy that the approach of reliably earthing the metal
> handles will reduce the electric shock risk in the context of the
> equipment, this approach being consistent with other safety standards I
> know like 62368-1 and 61010-1. I just can’t rationalise this with clause
> 22.36. As I say, I’m sure I’ve misread or misunderstood something so any
> help would be greatly appreciated.
>
> Otherwise, if anyone has a link to an explanatory document or contact for
> someone who could help at standards or committee level again that would
> help.
>
> All the best
> James
>
> James Pawson
> Managing Director & EMC Problem Solver
>
>
> *Office hours: *
>
> *My mornings are reserved for full attention on consultancy, testing, and
> troubleshooting activities for our customers’ projects. I am otherwise
> contactable between 1300h to 1730h from Monday to Friday. For inquiries,
> 

Re: [PSES] Safety: 60335-1 conflicting clauses question - earthing (or not) of handles

[Ken Javor]

I may be missing something but the way I read it they provide you with two
different approaches to reducing the hazard of electric shock. One is
protective earth grounding, and the other is double insulation, or double
electrically isolated. These are mutually exclusive, being two different
approaches to achieving the same goal.

Ken Javor
Phone: (256) 650-5261



From: "Grasso, Charles" 
Reply-To: "Grasso, Charles" 
Date: Wed, 5 Apr 2023 07:41:02 -0600
To: 
Subject: Re: [PSES] Safety: 60335-1 conflicting clauses question - earthing
(or not) of handles

How exactly does one measure "likely" as in likely to touch? Is it a %age?
Of course my question is tongue in cheek...

On Wed, Apr 5, 2023, 4:23 AM James Pawson (U3C)
 wrote:
>  This message originated outside of DISH and was sent by:
> ja...@unit3compliance.co.uk
> 
> 
> Hello experts,
>  
> In running through some safety checks on a customer¹s product I¹ve come across
> what appears to be a conflict between two clauses. This resulted in some head
> scratching! I¹m sure it is my misunderstanding or misreading, but I could do
> with some pointers in how to unpick this.
>  
> Context
> * Standard is IEC EN 60335-1:2012 (+amendments)
> * Context is an exercise machine (the appliance)
> * Supply is AC mains Class I
> * Appliance has metal handles that are held during normal use. These are
> connected through bearings to the metal frame but are not ³reliably earthed²
> (no explicit wired connection)
>  
> Earthing of metal parts is acceptable
> 22.35 For constructions other than those of class III, handles, levers and
> knobs that are held or actuated in normal use shall not become live in the
> event of a failure of basic insulation. If these handles, levers and knobs are
> of metal and if their shafts or fixings are likely to become live in the event
> of a failure of basic insulation, they shall be adequately covered by
> insulating material or their accessible parts shall be separated from their
> shafts or fixings by supplementary insulation.
>  
> For stationary appliances and cordless appliances, this requirement does not
> apply to handles, levers and knobs, other than those of electrical components,
> provided that they are reliably connected to an earthing terminal or earthing
> contact or separated from live parts by earthed metal.
>  
> * Class I appliance, with metal handles held during use so this requirement is
> applicable 
> * Handles are not reliably earthed so we are advising manufacturer to make an
> explicit bond to PE
> * With Basic insulation and Earthing we have our two safeguards between live
> and user = reduced risk of shock
> * No complaints with this clause
>  
> Earthing of metal parts is not accpetable
> Then the next clause seems to contradict this:
>  
> 22.36 For appliances other than those of class III, handles which are
> continuously held in the hand in normal use shall be constructed so that when
> gripped in normal use, the operator's hand is not likely to touch metal parts
> unless they are separated from live parts by double insulation or reinforced
> insulation
>  
> * This clause appears to not allow for earthing of the metal handles
> * Instead, only rouble or reinforced insulation are acceptable
> * Thoughts / speculation:
> o   Would this clause make more sense if it read ³For appliances other than
> those of class IŠ²? i.e. unearthed
> 
> o   Talks about ³appliances² (whole product) rather than ³constructions²
> (parts of appliance)
> 
>  
> Conclusion
> I¹m happy that the approach of reliably earthing the metal handles will reduce
> the electric shock risk in the context of the equipment, this approach being
> consistent with other safety standards I know like 62368-1 and 61010-1. I just
> can¹t rationalise this with clause 22.36. As I say, I¹m sure I¹ve misread or
> misunderstood something so any help would be greatly appreciated.
>  
> Otherwise, if anyone has a link to an explanatory document or contact for
> someone who could help at standards or committee level again that would help.
>  
> All the best
> James
>  
> James Pawson
> Managing Director & EMC Problem Solver
>  
> Office hours:
> My mornings are reserved for full attention on consultancy, testing, and
> troubleshooting activities for our customers¹ projects. I am otherwise
> 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.
>  
> 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

Re: [PSES] Safety: 60335-1 conflicting clauses question - earthing (or not) of handles

[Chas Grasso]

How exactly does one measure "likely" as in likely to touch? Is it a %age?
Of course my question is tongue in cheek...

On Wed, Apr 5, 2023, 4:23 AM James Pawson (U3C) 
wrote:

> * This message originated outside of DISH and was sent by:
> ja...@unit3compliance.co.uk  *
> --
>
> Hello experts,
>
>
>
> In running through some safety checks on a customer’s product I’ve come
> across what appears to be a conflict between two clauses. This resulted in
> some head scratching! I’m sure it is my misunderstanding or misreading, but
> I could do with some pointers in how to unpick this.
>
>
>
> *Context*
>
>- Standard is IEC EN 60335-1:2012 (+amendments)
>- Context is an exercise machine (the appliance)
>- Supply is AC mains Class I
>- Appliance has metal handles that are held during normal use. These
>are connected through bearings to the metal frame but are not “reliably
>earthed” (no explicit wired connection)
>
>
>
> *Earthing of metal parts is acceptable*
>
> *22.35 For constructions other than those of class III, handles, levers
> and knobs that are held or actuated in normal use shall not become live in
> the event of a failure of basic insulation. If these handles, levers and
> knobs are of metal and if their shafts or fixings are likely to become live
> in the event of a failure of basic insulation, they shall be adequately
> covered by insulating material or their accessible parts shall be separated
> from their shafts or fixings by supplementary insulation.*
>
>
>
> *For stationary appliances and cordless appliances, this requirement does
> not apply to handles, levers and knobs, other than those of electrical
> components, provided that they are reliably connected to an earthing
> terminal or earthing contact or separated from live parts by earthed metal.*
>
>
>
>- Class I appliance, with metal handles held during use so this
>requirement is applicable
>- Handles are not reliably earthed so we are advising manufacturer to
>make an explicit bond to PE
>- With Basic insulation and Earthing we have our two safeguards
>between live and user = reduced risk of shock
>- No complaints with this clause
>
>
>
> *Earthing of metal parts is not accpetable*
>
> Then the next clause seems to contradict this:
>
>
>
> *22.36 For appliances other than those of class III, handles which are
> continuously held in the hand in normal use shall be constructed so that
> when gripped in normal use, the operator's hand is not likely to touch
> metal parts unless they are separated from live parts by double insulation
> or reinforced insulation*
>
>
>
>- This clause appears to *not* allow for earthing of the metal handles
>- Instead, only rouble or reinforced insulation are acceptable
>- Thoughts / speculation:
>
> o   Would this clause make more sense if it read “For appliances other
> than those of class I…”? i.e. unearthed
>
> o   Talks about “appliances” (whole product) rather than “constructions”
> (parts of appliance)
>
>
>
> *Conclusion*
>
> I’m happy that the approach of reliably earthing the metal handles will
> reduce the electric shock risk in the context of the equipment, this
> approach being consistent with other safety standards I know like 62368-1
> and 61010-1. I just can’t rationalise this with clause 22.36. As I say, I’m
> sure I’ve misread or misunderstood something so any help would be greatly
> appreciated.
>
>
>
> Otherwise, if anyone has a link to an explanatory document or contact for
> someone who could help at standards or committee level again that would
> help.
>
>
>
> All the best
>
> James
>
>
>
> James Pawson
>
> Managing Director & EMC Problem Solver
>
>
>
> *Office hours:*
>
> *My mornings are reserved for full attention on consultancy, testing, and
> troubleshooting activities for our customers’ projects. I am otherwise
> 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.*
>
>
>
> *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
>
>
> -
> 
>
> 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 
> emc-p...@ieee.org
>
> All emc-pstc postings are archived and searchable on the web at:
> http://www.ieee-pses.org/emc-pstc.html
> 
>
> Website: http://www.ieee-pses.org/
> 
> 

[PSES] Safety: 60335-1 conflicting clauses question - earthing (or not) of handles

[James Pawson (U3C)]

Hello experts,

 

In running through some safety checks on a customer's product I've come
across what appears to be a conflict between two clauses. This resulted in
some head scratching! I'm sure it is my misunderstanding or misreading, but
I could do with some pointers in how to unpick this.

 

Context

*   Standard is IEC EN 60335-1:2012 (+amendments)
*   Context is an exercise machine (the appliance)
*   Supply is AC mains Class I
*   Appliance has metal handles that are held during normal use. These
are connected through bearings to the metal frame but are not "reliably
earthed" (no explicit wired connection)

 

Earthing of metal parts is acceptable

22.35 For constructions other than those of class III, handles, levers and
knobs that are held or actuated in normal use shall not become live in the
event of a failure of basic insulation. If these handles, levers and knobs
are of metal and if their shafts or fixings are likely to become live in the
event of a failure of basic insulation, they shall be adequately covered by
insulating material or their accessible parts shall be separated from their
shafts or fixings by supplementary insulation.

 

For stationary appliances and cordless appliances, this requirement does not
apply to handles, levers and knobs, other than those of electrical
components, provided that they are reliably connected to an earthing
terminal or earthing contact or separated from live parts by earthed metal.

 

*   Class I appliance, with metal handles held during use so this
requirement is applicable
*   Handles are not reliably earthed so we are advising manufacturer to
make an explicit bond to PE
*   With Basic insulation and Earthing we have our two safeguards
between live and user = reduced risk of shock
*   No complaints with this clause

 

Earthing of metal parts is not accpetable

Then the next clause seems to contradict this:

 

22.36 For appliances other than those of class III, handles which are
continuously held in the hand in normal use shall be constructed so that
when gripped in normal use, the operator's hand is not likely to touch metal
parts unless they are separated from live parts by double insulation or
reinforced insulation

 

*   This clause appears to not allow for earthing of the metal handles
*   Instead, only rouble or reinforced insulation are acceptable
*   Thoughts / speculation:

o   Would this clause make more sense if it read "For appliances other than
those of class I."? i.e. unearthed

o   Talks about "appliances" (whole product) rather than "constructions"
(parts of appliance)

 

Conclusion

I'm happy that the approach of reliably earthing the metal handles will
reduce the electric shock risk in the context of the equipment, this
approach being consistent with other safety standards I know like 62368-1
and 61010-1. I just can't rationalise this with clause 22.36. As I say, I'm
sure I've misread or misunderstood something so any help would be greatly
appreciated.

 

Otherwise, if anyone has a link to an explanatory document or contact for
someone who could help at standards or committee level again that would
help.

 

All the best

James

 

James Pawson

Managing Director & EMC Problem Solver

 

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