Re: [PSES] SV: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

[Gert Gremmen]

This is clearly marked in column (5) of the list of harmonised standards

"Date of cessation of presumption of conformity of superseded standard"

even if it is not listed in Column (2)

With the remark that EN 60950-1:2006 should not be applied for new 
presumptions of conformity.



Gert Gremmen
--
Independent Expert on CE marking
Harmonised Standards (HAS-) Consultant @ European Commission for RED and EMC
EMC Consultant
Electrical Safety Consultant


On 8-9-2018 10:14, Amund Westin wrote:


Thanks for this clarification, Loerzer.

I think we will use EN62368-1 now anyway, since 2020-12-20 is just 
around the corner.


BR Amund

*Fra:*loerzer_mob...@globalnorm.de 
*Sendt:* 8. september 2018 09:45
*Til:* 'Amund Westin' ; 
EMC-PSTC@LISTSERV.IEEE.ORG

*Emne:* AW: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

Hi Amund,

that is a „long story“ (caused by the so-called James Elliott Case 
C-613/14 and the Global Garden Case T-474/15). One consequence is the 
changed publication strategy of harmonized standards in the OJEU of 
theCommission (ref.: GROW/B3/AV/dn(2015)4821974). Annex III of this 
document describes under no. 9 for the LVD the following:


“c) All rows still giving references (in column (2)) of withdrawn and 
superseded standards MUST BE REMOVED from the list. Superseded 
standards and related “dates of cessation” are given in (4) and (5) 
columns only.”


The same situation is given for RED and EMCD.

Therefore the superseded standard EN 60950-1 and the amendments GIVES 
presumption of conformity until 2020-12-20 (my birthday…).


*Von:*Amund Westin <mailto:am...@westin-emission.no>>

*Gesendet:* Samstag, 8. September 2018 09:12
*An:* EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>
*Betreff:* [PSES] EN60950-1 not listed anymore as LVD harmonized standard

From June 15, 2018

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52018XC0615(04) 
<https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52018XC0615%2804%29>


What’s the reason? EN 62368-1 in not mandatory before 20.12.2020, so 
we should still be able to use EN60950-1:2006.


BR

Amund

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--
Independent Expert on CE marking
Harmonised Standards (HAS-) Consultant @ European Commission for RED and EMC
EMC Consultant
Electrical Safety Consultant


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[PSES] AW: [PSES] SV: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

[Michael Loerzer]

Have a nice day (without standards..).

 

Michael

 

Von: Amund Westin  
Gesendet: Samstag, 8. September 2018 10:14
An: EMC-PSTC@LISTSERV.IEEE.ORG
Betreff: [PSES] SV: [PSES] EN60950-1 not listed anymore as LVD harmonized
standard

 

Thanks for this clarification, Loerzer.

I think we will use EN62368-1 now anyway, since 2020-12-20 is just around
the corner.

 

BR Amund

 

Fra: loerzer_mob...@globalnorm.de <mailto:loerzer_mob...@globalnorm.de>
mailto:loerzer_mob...@globalnorm.de> > 
Sendt: 8. september 2018 09:45
Til: 'Amund Westin' mailto:am...@westin-emission.no> >; EMC-PSTC@LISTSERV.IEEE.ORG
<mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Emne: AW: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

 

Hi Amund,

 

that is a "long story" (caused by the so-called James Elliott Case C-613/14
and the Global Garden Case T-474/15). One consequence is the changed
publication strategy of harmonized standards in the OJEU of theCommission
(ref.: GROW/B3/AV/dn(2015)4821974). Annex III of this document describes
under no. 9 for the LVD the following:

 

"c) All rows still giving references (in column (2)) of withdrawn and
superseded standards MUST BE REMOVED from the list. Superseded standards and
related "dates of cessation" are given in (4) and (5) columns only."

 

The same situation is given for RED and EMCD.

 

Therefore the superseded standard EN 60950-1 and the amendments GIVES
presumption of conformity until 2020-12-20 (my birthday.).

 

 

 



 

Von: Amund Westin mailto:am...@westin-emission.no> > 
Gesendet: Samstag, 8. September 2018 09:12
An: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Betreff: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

 

>From June 15, 2018

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52018XC0615(04)

What's the reason?  EN 62368-1 in not mandatory before 20.12.2020, so we
should still be able to use EN60950-1:2006.

BR

Amund

-


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[PSES] SV: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

[Amund Westin]

Thanks for this clarification, Loerzer.

I think we will use EN62368-1 now anyway, since 2020-12-20 is just around
the corner.

 

BR Amund

 

Fra: loerzer_mob...@globalnorm.de  
Sendt: 8. september 2018 09:45
Til: 'Amund Westin' ; EMC-PSTC@LISTSERV.IEEE.ORG
Emne: AW: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

 

Hi Amund,

 

that is a "long story" (caused by the so-called James Elliott Case C-613/14
and the Global Garden Case T-474/15). One consequence is the changed
publication strategy of harmonized standards in the OJEU of theCommission
(ref.: GROW/B3/AV/dn(2015)4821974). Annex III of this document describes
under no. 9 for the LVD the following:

 

"c) All rows still giving references (in column (2)) of withdrawn and
superseded standards MUST BE REMOVED from the list. Superseded standards and
related "dates of cessation" are given in (4) and (5) columns only."

 

The same situation is given for RED and EMCD.

 

Therefore the superseded standard EN 60950-1 and the amendments GIVES
presumption of conformity until 2020-12-20 (my birthday.).

 

 

 



 

Von: Amund Westin mailto:am...@westin-emission.no> > 
Gesendet: Samstag, 8. September 2018 09:12
An: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Betreff: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

 

>From June 15, 2018

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52018XC0615(04)

What's the reason?  EN 62368-1 in not mandatory before 20.12.2020, so we
should still be able to use EN60950-1:2006.

BR

Amund

-


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discussion list. To post a message to the list, send your e-mail to
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[PSES] AW: [PSES] AW: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

[Michael Loerzer]

Sorry, I forgot my name as sender.

 

Dipl.-Ing. (FH) Michael Loerzer

Managing Director
Regulatory Affairs Specialist

 

Chairman Product Conformity Topic Group of the German Committee of Standards
Users in DIN (ANP-TGP)

Member of the IEEE Product Safety Engineering Society (PSES)

Member of the Radio Equipment Compliance Association (REDCA)

Chairman of the working group "Product Compliance" of the Network Compliance

 

 

Globalnorm GmbH

Kurfuerstenstr. 112

10787 Berlin, Germany

 

Phone +49 30 3229027-51

Cell +49 170 3229027

Fax +49 30 3229027-59

Mail <mailto:michael.loer...@globalnorm.de>
michael.loer...@globalnorm.de

 

 <http://www.globalnorm.de/> > globalnorm.de

 <http://www.globalnorm.de/en/services/newsletter.html> > Subscribe to the
GLOBALNORM Product Compliance Newsletter now.

 

Globalnorm GmbH

Headquarter: Kurfuerstenstr. 112, 10787 Berlin, Germany

Managing Director: Dipl.-Ing. Michael Loerzer

Registry court: Berlin-Charlottenburg HRB 105204 B, VAT-ID-Nummer:
DE251654448

 

 

 

Von: Michael Loerzer  
Gesendet: Samstag, 8. September 2018 09:45
An: EMC-PSTC@LISTSERV.IEEE.ORG
Betreff: [PSES] AW: [PSES] EN60950-1 not listed anymore as LVD harmonized
standard

 

Hi Amund,

 

that is a "long story" (caused by the so-called James Elliott Case C-613/14
and the Global Garden Case T-474/15). One consequence is the changed
publication strategy of harmonized standards in the OJEU of theCommission
(ref.: GROW/B3/AV/dn(2015)4821974). Annex III of this document describes
under no. 9 for the LVD the following:

 

"c) All rows still giving references (in column (2)) of withdrawn and
superseded standards MUST BE REMOVED from the list. Superseded standards and
related "dates of cessation" are given in (4) and (5) columns only."

 

The same situation is given for RED and EMCD.

 

Therefore the superseded standard EN 60950-1 and the amendments GIVES
presumption of conformity until 2020-12-20 (my birthday.).

 

 

 



 

Von: Amund Westin mailto:am...@westin-emission.no> > 
Gesendet: Samstag, 8. September 2018 09:12
An: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Betreff: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

 

>From June 15, 2018

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52018XC0615(04)

What's the reason?  EN 62368-1 in not mandatory before 20.12.2020, so we
should still be able to use EN60950-1:2006.

BR

Amund

-


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
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-


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Attachments are not permitted but the IEEE PSES Online Communities site at
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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://

[PSES] AW: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

[Michael Loerzer]

Hi Amund,

 

that is a "long story" (caused by the so-called James Elliott Case C-613/14
and the Global Garden Case T-474/15). One consequence is the changed
publication strategy of harmonized standards in the OJEU of theCommission
(ref.: GROW/B3/AV/dn(2015)4821974). Annex III of this document describes
under no. 9 for the LVD the following:

 

"c) All rows still giving references (in column (2)) of withdrawn and
superseded standards MUST BE REMOVED from the list. Superseded standards and
related "dates of cessation" are given in (4) and (5) columns only."

 

The same situation is given for RED and EMCD.

 

Therefore the superseded standard EN 60950-1 and the amendments GIVES
presumption of conformity until 2020-12-20 (my birthday.).

 

 

 



 

Von: Amund Westin  
Gesendet: Samstag, 8. September 2018 09:12
An: EMC-PSTC@LISTSERV.IEEE.ORG
Betreff: [PSES] EN60950-1 not listed anymore as LVD harmonized standard

 

>From June 15, 2018

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52018XC0615(04)

What's the reason?  EN 62368-1 in not mandatory before 20.12.2020, so we
should still be able to use EN60950-1:2006.

BR

Amund

-


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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Attachments are not permitted but the IEEE PSES Online Communities site at
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http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

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Scott Douglas 
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For policy questions, send mail to:
Jim Bacher:  
David Heald: 

[PSES] EN60950-1 not listed anymore as LVD harmonized standard

[Amund Westin]

>From June 15, 2018

https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:52018XC0615(04)

What's the reason?  EN 62368-1 in not mandatory before 20.12.2020, so we
should still be able to use EN60950-1:2006.

BR

Amund


-

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 


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Attachments are not permitted but the IEEE PSES Online Communities site at 
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formats), large files, etc.

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Re: [PSES] EN60950-1 dates and amendments

[John Allen]

About 20 yrs ago, I had exactly the problem that Rich outlines in paras 2 & 3, 
but in a somewhat different context, when I took on a job in the defence 
industry which appeared to require 60950 knowledge but then I found out (which 
the company did not really “get” for quite a few months/years thereafter!) that 
the real target requirement was for Hazard (severity/probability)-based safety 
cases for the UK MoD. 

 

Took me a few years to get reasonably comfortable with the whole concept and 
its implications and intricacies – but that stood me in good stead in a number 
of the jobs that followed, and right up to the very last contract job which 
finished last year. In that case I had, again, to educate that part of the 
company into the whole process of risk assessment for 61010-1 evaluations as my 
predecessor had declared it to be “Not Applicable” because 1) he was an EMC 
engineer (J), & 2) he had no idea of what it involved and so, somehow, 
persuaded the management that it was “N/A” - whereas it was absolutely 
necessary because of the inherent issues in the designs of many products!.

 

John E Allen

W. London, UK

 

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: 24 December 2016 00:18
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EN60950-1 dates and amendments

 

 

Hi Vincent:

 

ECMA has published a comparison (differences) between 60950-1 and 62368-1, 1st 
edition:

 

https://www.ecma-international.org/publications/files/ECMA-TR/ECMA%20TR-106.pdf

 

“Difficult to pass” depends on familiarity with 60950.  Those familiar and 
experienced with 60950 will find 62368 very difficult.  In my opinion, those 
who are new to product safety probably will find 62368 easier to understand.   

 

There are very few hardware differences between the two standards.  The 
approach in 62368 is to separate the requirements (safeguards) according to 
“hazard” whereas 60950 has the requirements for different “hazards” mixed up so 
that someone who is applying the standard doesn’t know what the requirements 
protect against.   

 

Best wishes for the holiday season,

Rich

 

 

From: Vincent Lee [mailto:08e6c8d35910-dmarc-requ...@ieee.org] 
Sent: Friday, December 23, 2016 3:09 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EN60950-1 dates and amendments

 

Hi all,

 

May I know what are the major differences between IEC 60950-1 and IEC 62368-1 
(2nd ed) ?

 

Which is more difficult to pass in product safety for IT equipment ?

 

Hope to hear from you soon. 

 

Thank You & Happy Holiday.

 

Regards, Vincent

 

-


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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.

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Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 
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This message is from the IEEE Product Safety Engineering Society emc-pstc 
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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 
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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

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Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

Re: [PSES] EN60950-1 dates and amendments

[Pete Perkins]

Vincent et al,  

 

Thanx to Rich Nute for chiming in here.  Rich is the originator 
and promoter of Hazard Based Safety Engineering the principles of which are 
incorporated into 62368-1.  

 

Altho the transition may be difficult for some, the new  HBStd 
provides a better platform for providing safe products as the technology 
changes.  However, It is fair to point out that since the standard is 
continuing to be clarified it is felt by many of those providing input to the 
requirements that products developed under 60950 should also be acceptable 
under 62368 under most circumstances.  

 

So I agree with some of the other commenters (who are both on 
this standards committee and work for companies that are working to use the new 
standard for their products) that other companies which have not started to 
learn the new standard and determine how it will affect their products is a 
step behind the curve at this point.  Safety & regulatory staff need to get the 
needed starter training to quickly implement the evaluation of product designs 
to the new standard and point out weaknesses to the design teams so that 
corrective action can be taken on these new designs to keep them from running 
into issues during the inevitable upgrade certification process which is fast 
approaching.  

 

In addition to the private training seminars which have been 
available for some time the IEEE PSES symposium have had discussions and papers 
on many of the internal issues on an ongoing basis.  

 

A good company strategy should proceed on several fronts simultaneously 
feedback – in addition to the needed training a flagship product should be 
submitted to a 62368 certification evaluation to get feedback on issues needing 
resolution. 

 

Good luck in moving ahead in the transition to 62368.  

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

 <mailto:p.perk...@ieee.org> p.perk...@ieee.org

 

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Friday, December 23, 2016 4:18 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EN60950-1 dates and amendments

 

 

Hi Vincent:

 

ECMA has published a comparison (differences) between 60950-1 and 62368-1, 1st 
edition:

 

https://www.ecma-international.org/publications/files/ECMA-TR/ECMA%20TR-106.pdf

 

“Difficult to pass” depends on familiarity with 60950.  Those familiar and 
experienced with 60950 will find 62368 very difficult.  In my opinion, those 
who are new to product safety probably will find 62368 easier to understand.   

 

There are very few hardware differences between the two standards.  The 
approach in 62368 is to separate the requirements (safeguards) according to 
“hazard” whereas 60950 has the requirements for different “hazards” mixed up so 
that someone who is applying the standard doesn’t know what the requirements 
protect against.   

 

Best wishes for the holiday season,

Rich

 

 

From: Vincent Lee [mailto:08e6c8d35910-dmarc-requ...@ieee.org] 
Sent: Friday, December 23, 2016 3:09 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: Re: [PSES] EN60950-1 dates and amendments

 

Hi all,

 

May I know what are the major differences between IEC 60950-1 and IEC 62368-1 
(2nd ed) ?

 

Which is more difficult to pass in product safety for IT equipment ?

 

Hope to hear from you soon. 

 

Thank You & Happy Holiday.

 

Regards, Vincent

 

-


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: 
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) 
<http://www.ieee-pses.org/list.html> 
List rules: http://www.ieee-pses.org/listrules.html 

For help, send mail to the list administrators:
Scott Douglas mailto:sdoug...@ieee.org> >
Mike Cantwell mailto:mcantw...@ieee.org> > 

For policy questions, send mail to:
Jim Bacher mailto:j.bac...@ieee.org> >
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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 permitt

Re: [PSES] EN60950-1 dates and amendments

[John Woodgate]

Roughly speaking, everything is different. 62368-1 uses the 'hazard-based' 
principle to determine what should be specified  and how compliance is to be 
determined. 
 
In some, but by no means all, cases, this new approach results in a similar or 
near-identical compliant product,, but that is arrived at by a very different 
route. You really have little choice but to obtain both 62489-1 and its 
supporting document 62489-2 and learn them. It would be good to take in an 
extended training course as well.
 
A further complication is that the standard is still not stable – a third 
edition is in process.
 
With best wishes DESIGN IT IN! OOO – Own Opinions Only
 <http://www.jmwa.demon.co.uk/> www.jmwa.demon.co.uk J M Woodgate and 
Associates Rayleigh England
 
Sylvae in aeternum manent.
 
From: Vincent Lee [mailto:08e6c8d35910-dmarc-requ...@ieee.org] 
Sent: Friday, December 23, 2016 11:09 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EN60950-1 dates and amendments
 
Hi all,
 
May I know what are the major differences between IEC 60950-1 and IEC 62368-1 
(2nd ed) ?
 
Which is more difficult to pass in product safety for IT equipment ?
 
Hope to hear from you soon. 
 
Thank You & Happy Holiday.
 
Regards, Vincent
 
  _  

From: Ted Eckert <07cf6ebeab9d-dmarc-requ...@ieee.org 
<mailto:07cf6ebeab9d-dmarc-requ...@ieee.org> >
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>  
Sent: Friday, December 9, 2016 12:26 AM
Subject: Re: [PSES] EN60950-1 dates and amendments
 
The European Commission has a web page covering the NLF LVD.
http://ec.europa.eu/growth/sectors/electrical-engineering/lvd-directive_en
 
There is a link to the standards 
<https://ec.europa.eu/growth/single-market/european-standards/harmonised-standards/low-voltage_en>
  near the bottom. Search for “60950-1” to see the amendments currently 
applied. Search for “62368-1” to see the date of withdrawal of EN 60950-1.
 
Underwriters Laboratories maintains a web page covering the transition dates at 
the following link.
http://industries.ul.com/blog/effective-date-information
 
The European Union and North America have a different approach to the 
transition to IEC 62368-1. 
 
On 20 June, 2019, any IT or A/V product placed on the market for which the 
manufacturer declares conformity through compliance with the standards must 
comply with EN 62368-1 regardless of when it was first placed on the market. A 
manufacturer would need to declare all of their IT and A/V products to EN 
62368-1. 
 
On 20 June, 2019, Underwriters Laboratories will no longer test or certify 
products to UL 60950-1 and products will need to be tested to UL 62368-1. 
However, products certified to UL 60950-1 prior to that date may continue to be 
sold without retesting or recertification unless such equipment undergoes 
“significant” modification where it will be up to UL to determine whether any 
modification is significant enough to warrant testing to the new standard.
 
Best regards,
Ted Eckert
Microsoft Corporation
 
The opinions expressed are my own and do not necessarily reflect those of my 
employer.
 
From: McBurney, Ian [mailto:ian.mcbur...@allen-heath.com] 
Sent: Thursday, December 8, 2016 6:57 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] EN60950-1 dates and amendments
 
Dear colleagues.
 
With the change to the European Union LVD and the requirements regarding 
declaring compliance, what version of EN 60950-1and its amendments are 
acceptable and is there an expiry date?
Does the UL version have similar expiry dates?
 
Many thanks in advance.
 
Ian McBurney
Design & Compliance Engineer.
 
Allen & Heath Ltd.
Kernick Industrial Estate,
Penryn, Cornwall. TR10 9LU. UK
T: 01326 372070
E: ian.mcbur...@allen-heath.com <mailto:ian.mcbur...@allen-heath.com> 
 
 
Allen & Heath Ltd is a registered business in England and Wales, Company 
number: 4163451. Any views expressed in this email are those of the individual 
and not necessarily those of the company. 
-

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: 
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) 
<http://www.ieee-pses.org/list.html> 
List rules: http://www.ieee-pses.org/listrules.html 
For help, send mail to the list administrators:
Scott Douglas mailto:sdoug...@ieee.org> >
Mike Cantwell mailto:mcantw...@ieee.org> 

Re: [PSES] EN60950-1 dates and amendments

[Richard Nute]

 

Hi Vincent:

 

ECMA has published a comparison (differences) between 60950-1 and 62368-1, 1st 
edition:

 

https://www.ecma-international.org/publications/files/ECMA-TR/ECMA%20TR-106.pdf

 

“Difficult to pass” depends on familiarity with 60950.  Those familiar and 
experienced with 60950 will find 62368 very difficult.  In my opinion, those 
who are new to product safety probably will find 62368 easier to understand.   

 

There are very few hardware differences between the two standards.  The 
approach in 62368 is to separate the requirements (safeguards) according to 
“hazard” whereas 60950 has the requirements for different “hazards” mixed up so 
that someone who is applying the standard doesn’t know what the requirements 
protect against.   

 

Best wishes for the holiday season,

Rich

 

 

From: Vincent Lee [mailto:08e6c8d35910-dmarc-requ...@ieee.org] 
Sent: Friday, December 23, 2016 3:09 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EN60950-1 dates and amendments

 

Hi all,

 

May I know what are the major differences between IEC 60950-1 and IEC 62368-1 
(2nd ed) ?

 

Which is more difficult to pass in product safety for IT equipment ?

 

Hope to hear from you soon. 

 

Thank You & Happy Holiday.

 

Regards, Vincent

 


-

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:
Scott Douglas 
Mike Cantwell 

For policy questions, send mail to:
Jim Bacher:  
David Heald: 

Re: [PSES] EN60950-1 dates and amendments

[Joe Randolph]

Hi Vincent:

 

IEC 60950-1 and IEC 62368-1 are completely different standards that have 
different structure, different terminology, and different approaches for 
evaluating compliance.  The main thing they have in common is that they both 
cover ITE.  IEC 60950-1 will eventually be phased out, but at the present time 
either standard can be used for ITE.

 

Many people who work with safety standards feel that IEC 62368-1 
“hazards-based” philosophy represents a more flexible and appropriate approach 
to the earlier “prescriptive” approach used in IEC 60950-1.  I think the main 
advantage to working with IEC 60950-1 is for people who are already familiar 
with it from previous projects.  If you have no familiarity with either 
standard, you may as well start now with IEC 32368-1.  

 

Check with you test lab, though, because some test labs remain more familiar 
with IEC 60950-1, and are likely to have less difficulty applying it than IEC 
62368-1.

 

 

Joe Randolph

Telecom Design Consultant

Randolph Telecom, Inc.

781-721-2848 (USA)

 <mailto:j...@randolph-telecom.com> j...@randolph-telecom.com

 <http://www.randolph-telecom.com> http://www.randolph-telecom.com

 

From: Vincent Lee [mailto:08e6c8d35910-dmarc-requ...@ieee.org] 
Sent: Friday, December 23, 2016 6:09 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] EN60950-1 dates and amendments

 

Hi all,

 

May I know what are the major differences between IEC 60950-1 and IEC 62368-1 
(2nd ed) ?

 

Which is more difficult to pass in product safety for IT equipment ?

 

Hope to hear from you soon. 

 

Thank You & Happy Holiday.

 

Regards, Vincent

 

  _  

From: Ted Eckert <07cf6ebeab9d-dmarc-requ...@ieee.org 
<mailto:07cf6ebeab9d-dmarc-requ...@ieee.org> >
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG>  
Sent: Friday, December 9, 2016 12:26 AM
Subject: Re: [PSES] EN60950-1 dates and amendments

 

The European Commission has a web page covering the NLF LVD.

http://ec.europa.eu/growth/sectors/electrical-engineering/lvd-directive_en

 

There is a link to the standards 
<https://ec.europa.eu/growth/single-market/european-standards/harmonised-standards/low-voltage_en>
  near the bottom. Search for “60950-1” to see the amendments currently 
applied. Search for “62368-1” to see the date of withdrawal of EN 60950-1.

 

Underwriters Laboratories maintains a web page covering the transition dates at 
the following link.

http://industries.ul.com/blog/effective-date-information

 

The European Union and North America have a different approach to the 
transition to IEC 62368-1. 

 

On 20 June, 2019, any IT or A/V product placed on the market for which the 
manufacturer declares conformity through compliance with the standards must 
comply with EN 62368-1 regardless of when it was first placed on the market. A 
manufacturer would need to declare all of their IT and A/V products to EN 
62368-1. 

 

On 20 June, 2019, Underwriters Laboratories will no longer test or certify 
products to UL 60950-1 and products will need to be tested to UL 62368-1. 
However, products certified to UL 60950-1 prior to that date may continue to be 
sold without retesting or recertification unless such equipment undergoes 
“significant” modification where it will be up to UL to determine whether any 
modification is significant enough to warrant testing to the new standard.

 

Best regards,

Ted Eckert

Microsoft Corporation

 

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

 

From: McBurney, Ian [mailto:ian.mcbur...@allen-heath.com] 
Sent: Thursday, December 8, 2016 6:57 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG <mailto:EMC-PSTC@LISTSERV.IEEE.ORG> 
Subject: [PSES] EN60950-1 dates and amendments

 

Dear colleagues.

 

With the change to the European Union LVD and the requirements regarding 
declaring compliance, what version of EN 60950-1and its amendments are 
acceptable and is there an expiry date?

Does the UL version have similar expiry dates?

 

Many thanks in advance.

 

Ian McBurney

Design & Compliance Engineer.

 

Allen & Heath Ltd.

Kernick Industrial Estate,

Penryn, Cornwall. TR10 9LU. UK

T: 01326 372070

E: ian.mcbur...@allen-heath.com <mailto:ian.mcbur...@allen-heath.com> 

 

 

Allen & Heath Ltd is a registered business in England and Wales, Company 
number: 4163451. Any views expressed in this email are those of the individual 
and not necessarily those of the company. 

-


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: 
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-c

Re: [PSES] EN60950-1 dates and amendments

[Vincent Lee]

Hi all,
May I know what are the major differences between IEC 60950-1 and IEC 62368-1 
(2nd ed) ?
Which is more difficult to pass in product safety for IT equipment ?
Hope to hear from you soon. 
Thank You & Happy Holiday.
Regards, Vincent

  From: Ted Eckert <07cf6ebeab9d-dmarc-requ...@ieee.org>
 To: EMC-PSTC@LISTSERV.IEEE.ORG 
 Sent: Friday, December 9, 2016 12:26 AM
 Subject: Re: [PSES] EN60950-1 dates and amendments
   
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6 3 2 4;} _filtered #yiv7704880803 {font-family:Calibri;panose-1:2 15 5 2 2 2 4 
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span.yiv7704880803EmailStyle18 {color:windowtext;}#yiv7704880803 
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{margin:1.0in 1.0in 1.0in 1.0in;}#yiv7704880803 div.yiv7704880803WordSection1 
{}#yiv7704880803 The European Commission has a web page covering the NLF LVD. 
http://ec.europa.eu/growth/sectors/electrical-engineering/lvd-directive_en    
There is a link to the standards near the bottom. Search for “60950-1” to see 
the amendments currently applied. Search for “62368-1” to see the date of 
withdrawal of EN 60950-1.    Underwriters Laboratories maintains a web page 
covering the transition dates at the following link. 
http://industries.ul.com/blog/effective-date-information    The European Union 
and North America have a different approach to the transition to IEC 62368-1.   
 On 20 June, 2019, any IT or A/V product placed on the market for which the 
manufacturer declares conformity through compliance with the standards must 
comply with EN 62368-1 regardless of when it was first placed on the market. A 
manufacturer would need to declare all of their IT and A/V products to EN 
62368-1.    On 20 June, 2019, Underwriters Laboratories will no longer test or 
certify products to UL 60950-1 and products will need to be tested to UL 
62368-1. However, products certified to UL 60950-1 prior to that date may 
continue to be sold without retesting or recertification unless such equipment 
undergoes “significant” modification where it will be up to UL to determine 
whether any modification is significant enough to warrant testing to the new 
standard.    Best regards, Ted Eckert Microsoft Corporation    The opinions 
expressed are my own and do not necessarily reflect those of my employer.    
From: McBurney, Ian [mailto:ian.mcbur...@allen-heath.com]
Sent: Thursday, December 8, 2016 6:57 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] EN60950-1 dates and amendments    Dear colleagues.    With the 
change to the European Union LVD and the requirements regarding declaring 
compliance, what version of EN 60950-1and its amendments are acceptable and is 
there an expiry date? Does the UL version have similar expiry dates?    Many 
thanks in advance.    Ian McBurney Design & Compliance Engineer.    Allen & 
Heath Ltd. Kernick Industrial Estate, Penryn, Cornwall. TR10 9LU. UK T: 01326 
372070 E: ian.mcbur...@allen-heath.com       Allen & Heath Ltd is a registered 
business in England and Wales, Company number: 4163451. Any views expressed in 
this email are those of the individual and not necessarily those of the 
company.  -
 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:
Scott Douglas 
Mike Cantwell   For policy questions, send mail to:
Jim Bacher 
David Heald   -

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e

Re: [PSES] EN60950-1 dates and amendments

[Ted Eckert]

The European Commission has a web page covering the NLF LVD.
http://ec.europa.eu/growth/sectors/electrical-engineering/lvd-directive_en

There is a link to the 
standards<https://ec.europa.eu/growth/single-market/european-standards/harmonised-standards/low-voltage_en>
 near the bottom. Search for "60950-1" to see the amendments currently applied. 
Search for "62368-1" to see the date of withdrawal of EN 60950-1.

Underwriters Laboratories maintains a web page covering the transition dates at 
the following link.
http://industries.ul.com/blog/effective-date-information

The European Union and North America have a different approach to the 
transition to IEC 62368-1.

On 20 June, 2019, any IT or A/V product placed on the market for which the 
manufacturer declares conformity through compliance with the standards must 
comply with EN 62368-1 regardless of when it was first placed on the market. A 
manufacturer would need to declare all of their IT and A/V products to EN 
62368-1.

On 20 June, 2019, Underwriters Laboratories will no longer test or certify 
products to UL 60950-1 and products will need to be tested to UL 62368-1. 
However, products certified to UL 60950-1 prior to that date may continue to be 
sold without retesting or recertification unless such equipment undergoes 
"significant" modification where it will be up to UL to determine whether any 
modification is significant enough to warrant testing to the new standard.

Best regards,
Ted Eckert
Microsoft Corporation

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

From: McBurney, Ian [mailto:ian.mcbur...@allen-heath.com]
Sent: Thursday, December 8, 2016 6:57 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] EN60950-1 dates and amendments

Dear colleagues.

With the change to the European Union LVD and the requirements regarding 
declaring compliance, what version of EN 60950-1and its amendments are 
acceptable and is there an expiry date?
Does the UL version have similar expiry dates?

Many thanks in advance.

Ian McBurney
Design & Compliance Engineer.

Allen & Heath Ltd.
Kernick Industrial Estate,
Penryn, Cornwall. TR10 9LU. UK
T: 01326 372070
E: ian.mcbur...@allen-heath.com<mailto:ian.mcbur...@allen-heath.com>


Allen & Heath Ltd is a registered business in England and Wales, Company 
number: 4163451. Any views expressed in this email are those of the individual 
and not necessarily those of the company.
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[PSES] EN60950-1 dates and amendments

[McBurney, Ian]

Dear colleagues.

With the change to the European Union LVD and the requirements regarding 
declaring compliance, what version of EN 60950-1and its amendments are 
acceptable and is there an expiry date?
Does the UL version have similar expiry dates?

Many thanks in advance.

Ian McBurney
Design & Compliance Engineer.

Allen & Heath Ltd.
Kernick Industrial Estate,
Penryn, Cornwall. TR10 9LU. UK
T: 01326 372070
E: ian.mcbur...@allen-heath.com


Allen & Heath Ltd is a registered business in England and Wales, Company 
number: 4163451. Any views expressed in this email are those of the individual 
and not necessarily those of the company.

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[PSES] SV: [PSES] EN60950-1 .... A11:2009 scope

[Amund Westin]

Couldn't wait, so I had to buy it ... :)

#Amund



-Opprinnelig melding-
Fra: Amund Westin [mailto:am...@westin-emission.no] 
Sendt: 13. september 2012 09:46
Til: EMC-PSTC@LISTSERV.IEEE.ORG
Emne: [PSES] EN60950-1  A11:2009 scope

What is the scope of A11:2009?


Thanks.

Best regards
Amund

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[PSES] EN60950-1 .... A11:2009 scope

[Amund Westin]

What is the scope of A11:2009?


Thanks.

Best regards
Amund

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EN60950-1 and R&TTE directive TCF

[emc-p...@ieee.org]

Hi Guys  (R&TTE and LVD experts),

We  have understanding that EN/IEC60950-1 2005 with most recent amendments, 
that sec 1.3Z1 excessive sound pressure level compliance does not require 
testing per EN50332-1/2 based on the TC108 conclusion 

The meeting discussed above mentioned documents regarding sound pressure with 
the following results:
• references to EN 50332-1 and -2 in EN 60065 and EN 60950-1 (EN 60065␣note to 
clause 3.1 , EN 60950-1␣note to 1.3.Z1) A reference in a note is not normative. 
So, there is no obligation to use those standards. Conclusion: Compliance with 
EN 60065 or EN 60950-1 does not require compliance with EN 50332-1 or -2.

Clause 1.3.Z1 of this standard which is harmonized under the R&TTE Directive as 
well as under the Low Voltage Directive has the following requirement towards 
portable audio equipment:

 
The apparatus shall be so designed and constructed as to present no danger when 
used for its intended purpose, either in normal operating conditions or under 
fault conditions, particularly
providing protection against exposure to excessive sound pressures from 
headphones or earphones.

Now R&TTE directive compliance using TCF, insists on evidence to comply "with 
excessive sound pressure "



In the absence of defined "excessive sound pressure level" in the standard 
1.3Z1 , How one can demonstrate the evidence... Again 1.3Z1is a Note and Note 
is not considered as a requirement.


I would like to get the opinions of some NBs on this If possible and what is 
the kind of evidence is expected from manufacturer?




Thanks, 


Sudhakar 
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Re: [PSES] 2nd Edition Safety Implementation in Europe (EN60950-1:2006+A11:2009)

[emc-p...@ieee.org]

In message , dated Mon, 6 
Sep 2010, John  Cotman  writes:

>There is surely a more basic point to consider, too?

I'm sure there is a hierarchy of more basic points, but there is only so 
much that it is sensible to mention in a reply, otherwise it is liable 
to confuse the enquirer.
>
>Compliance with EN60950 (at any issue of the standard) is not a legal 
>requirement within the EU.  The legal requirement is compliance with 
>the Essential Health and Safety Requirements of any relevant 
>Directive(s) that apply to the product.

Agreed.
>
>Whilst using a harmonized standard is a common route of demonstrating 
>this EHSR compliance, (and it may often be a commercial contract 
>condition), it is not mandatory so far as the law is concerned.

Agreed.

> It would not be possible for an enforcement body within the EU to 
>bring an action merely on the basis that an "out of date" standard had 
>been applied to a product.

I do not agree; the 'docopocoss' quite clearly says 'date of cessation 
of presumption of conformity of the superseded standard'. So citing an 
out-of-date standard does not demonstrate conformity. I agree that it is 
only a 'formal offence' if the Essential Requirements are still 
satisfied, but it would be difficult in many cases to show that if the 
product did not conform to the new standard in a non-trivial way.
-- 
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
If at first you don't succeed, delegate.
But I support unbloated email http://www.asciiribbon.org/

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RE: [PSES] 2nd Edition Safety Implementation in Europe (EN60950-1:2006+A11:2009)

[emc-p...@ieee.org]

There is surely a more basic point to consider, too?

Compliance with EN60950 (at any issue of the standard) is not a legal
requirement within the EU.  The legal requirement is compliance with the
Essential Health and Safety Requirements of any relevant Directive(s) that
apply to the product.

Whilst using a harmonized standard is a common route of demonstrating this
EHSR compliance, (and it may often be a commercial contract condition), it
is not mandatory so far as the law is concerned.  It would not be possible
for an enforcement body within the EU to bring an action merely on the basis
that an "out of date" standard had been applied to a product.

Regards,

John Cotman

Conformance Ltd. - Product safety, approvals and CE-marking consultants.
Registered in England, Company No. 3478646

Old Methodist Chapel,
Great Hucklow,
BUXTON,
SK17 8RG,
UK.
Tel. +44 1298 873800
Fax. +44 1298 873801
www.conformance.co.uk

-Original Message-
From: John Woodgate [mailto:j...@jmwa.demon.co.uk] 
Sent: 04 September 2010 08:18
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] 2nd Edition Safety Implementation in Europe
(EN60950-1:2006+A11:2009)

In message <4c815ed8.5000...@oracle.com>, dated Fri, 3 Sep 2010, Monrad 
Monsen  writes:

>Do you interpret the European Union rules for implementing the new 
>EN60950-1:2006+A11:2009 (2nd Edition) safety standard on products the 
>same way that I do? 

No. Your message is far too long and complicated to address your points 
in context.

You have not taken 'placed on the market' into account. Products not 
complying with the new standard must be placed on the market, i.e. 
shipped by the manufacturer or, for imported products, by the importer 
in the EU, into the distribution chain before 1 December, but need not 
be taken into service by that date. Nominally, such products should be 
cleared from the distribution chin within about a year, but this is 
usually not policed and enforced. It does not apply in the rare case 
where the standard itself has been found to be seriously defective.

Your point 3 about servicing is correct.

You wrote:

  Others are only concerned about ensuring that only 2nd Edition 
compliant products are imported into Europe starting 1 December 2010. 

They are correct.

However, I am having difficulty finding manufacturers that are 
attempting to ensure that only 2nd Edition safety compliant products 
arrive at the ultimate customer's site and are installed ("put into 
service") on 1 December or later.

This is NOT necessary (and is impossible for the manufacturer to 
control!), as you have not taken 'placed on the market' into account, 
even though you cited Section 2.3.1 (page 18). Taking into service comes 
after placing on the market.
-- 
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
If at first you don't succeed, delegate.
But I support unbloated email http://www.asciiribbon.org/

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Re: 2nd Edition Safety Implementation in Europe (EN60950-1:2006+A11:2009)

[emc-p...@ieee.org]

In message <4c815ed8.5000...@oracle.com>, dated Fri, 3 Sep 2010, Monrad 
Monsen  writes:

>Do you interpret the European Union rules for implementing the new 
>EN60950-1:2006+A11:2009 (2nd Edition) safety standard on products the 
>same way that I do? 

No. Your message is far too long and complicated to address your points 
in context.

You have not taken 'placed on the market' into account. Products not 
complying with the new standard must be placed on the market, i.e. 
shipped by the manufacturer or, for imported products, by the importer 
in the EU, into the distribution chain before 1 December, but need not 
be taken into service by that date. Nominally, such products should be 
cleared from the distribution chin within about a year, but this is 
usually not policed and enforced. It does not apply in the rare case 
where the standard itself has been found to be seriously defective.

Your point 3 about servicing is correct.

You wrote:

  Others are only concerned about ensuring that only 2nd Edition 
compliant products are imported into Europe starting 1 December 2010. 

They are correct.

However, I am having difficulty finding manufacturers that are 
attempting to ensure that only 2nd Edition safety compliant products 
arrive at the ultimate customer's site and are installed ("put into 
service") on 1 December or later.

This is NOT necessary (and is impossible for the manufacturer to 
control!), as you have not taken 'placed on the market' into account, 
even though you cited Section 2.3.1 (page 18). Taking into service comes 
after placing on the market.
-- 
OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
If at first you don't succeed, delegate.
But I support unbloated email http://www.asciiribbon.org/

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2nd Edition Safety Implementation in Europe (EN60950-1:2006+A11:2009)

[emc-p...@ieee.org]

Do you interpret the European Union rules for implementing the new
EN60950-1:2006+A11:2009 (2nd Edition) safety standard on products the same way
that I do?  

EN60950-1:2006+A11:2009 (2nd Edition safety standard) becomes mandatory for
Information Technology Equipment (computers, etc.) on 1 December 2010
according to the "Official Journal of the European Union" 2010/C 71/02 on page
C71/66.  The only document that I have found that explains the implementation
process for standards updates is the European Commission's "Guide to the
Implementation of Directives Based on the New Approach and the Global
Approach" published in year 2000.  Based on this document, I believe the
implementation rules are as follows:
  1. Each individual serial number product must comply with the 
 2nd Edition safety standard if that individual product is 
 first put into service within Europe on 1 December 2010 or 
 later.  

  2. Individual serial number products complying only with 
 1st Edition safety (not 2nd Edition) would have to be 
 installed at the customer site and put into service by 
 30 November 2010.  

  3. Once the individual serial number product has been put 
 into service within Europe, then the product should be 
 maintained (repaired) in a manner that either keeps the 
 same safety compliance level or upgrades the product to 
 the latest edition of the safety standards.  In other 
 words, additional 1st Edition compliant repair or 
 replacement parts may be shipped into Europe to maintain 
 1st Edition safety compliant products already in use 
 within Europe

To achieve the above, that would mean that manufacturers would have to build
2nd Edition safety compliant product well in advance of the 1 December date to
ensure that the products have time to be shipped through customs and delivered
to the customer so the customer can install the product prior to 1 December. 
If a manufacturer sells services to have trained experts install the product
for the customer, that appointment to install the product would have to be set
for a date prior to 1 December for a product that only complies with the 1st
Edition safety standard.  

Do you agree with my interpretation described above?

If I am correct on the European Union rules, then many manufacturers are
failing to work to implement these rules.  Some are only ensuring that the
factory changes over to building 2nd Edition safety compliant products by 1
December 2010.  Others are only concerned about ensuring that only 2nd Edition
compliant products are imported into Europe starting 1 December 2010. 
However, I am having difficulty finding manufacturers that are attempting to
ensure that only 2nd Edition safety compliant products arrive at the ultimate
customer's site and are installed ("put into service") on 1 December or later.

SUPPORT BACKGROUND (FOR THOSE THAT HAVE NOT LOOKED AT THIS ISSUE)
The European Commission's "Guide to the Implementation of Directives Based on
the New Approach and the Global Approach" is available online at:
http://ec.europa.eu/enterprise/policies
single-market-goods/files/blue-guide/guidepublic_en.pdf 

Section 2.3.1 (page 18) states the following:



"Accordingly, the new products manufactured in the Community and all 
products
imported from third countries -- whether new or used -- must meet the
provisions of the applicable directives when made available for the first time
on the Community market."  

"Moreover, the concept of placing on the market refers to each 
individual
product, not to a type of product, and whether it was manufactured as an
individual unit or in series."


Section 2.3.2 (page 19) states the following:



* "Putting into service takes place at the moment of first use within 
the
Community by the end user."

* "Products must comply with the provisions of the applicable New 
Approach
directives and other Community legislation when they are put into service."



Based on the above quotes from section 2.3, the product must meet the current
directives and the current harmonized standards at the time the individual
serial number product is actually first put into service at the customer site.
 It does not matter that products of the same model number and build were
already sold within the Community prior to 1 December 2010, but the focus is
on the "individual product" and when it was "put into service".

Section 2.1 (page 16) states the following:



* "Products which have been repaired (for example following a defect),
without changing the original performance, purpose or type, are not to be
considered as new products according to the New Approach directives."

* "This applies even if the product has been temporarily exported to a 
third
country

RE: Need help with EN60950 for power supply

[emc-p...@ieee.org]

I do not think such a source exists.

 

In general:

Products need to be ce-marked according to the  regulations valid on: 

“date of putting on the market”  OR, 

“date of putting into service” , if (1)  is not applicable.

 

“Parts” that have an intrinsic function to the end user

(and bad luck: a power supply is explicitly mentioned in the guide to the
LVD/EMC)

are treated as apparatuses and thus need to be ce marked using the current
version of the standard (from the list

of harmonized standards), if they were not put on the EU market on an earlier
date.

That is so for all apparatuses. If the standard changes, production of the
apparatus and approval should be updated.

(to sell  current stock, a substantial amount of time is allowed , in which
old and new standards are both valid)

 

It depends on your warehouse and the status of it, to determine 

 if the part in it has been actually been “put on the Union market” .

If you are  the manufacturer, I’d say : No, it has not been put on the
market yet

so you need to comply with the new standards. 

If you are distributor, I’d say yes, these have been sold to a third party,
so “put on the market”.

The place of the warehouse (in or out the Union) will also influence that.

 

In a normal production and sales scenario the transition time will resolve any
conflicts.

 

In a repair scenario, old edition parts has been kept on stock on purpose:

 

The product to be repaired was approved using

the 1st edition , will not be compliant anymore using the power supply

approved to the 2nd edition (as it must be another part). In this approach you
could

service the apparatus exclusively with edition 1 parts, and edition 2 parts
would

annihilate the very  ce-marking of the apparatus being serviced.

That is the argument to be used here.

As in-use equipment approval need not be updated to a newer standard

I’d say this is a valid approach.

 

 

I think there is no real problem here, but you need to make

clear that you are importing and selling replacement parts , exclusively meant
for repair,

 and not “old stock”  that should have been updated.

In case of questions be prepared to argue why, or even better, supply

the “repair chain” with appropriate documents with each shipment.

 

 

And finally , a ce marking under the LVD a part need not

be approved using a safety standard at all. One may draw up a technical
construction file

proving it’s safety with an arbitrary collection of calculations and tests
and

use that as a basis for approval. The TCF may voluntarily be supported by

a statement from a notified body.

The word “arbitrary” means of course only that no reference to a standard
edition

need to be given, and the collection of test may include updated and

not updated clauses from both standards. But that may be an expensive route.

 

Hope this is clear, and that I did not forget anything.

 

Gert Gremmen

Ce-test, qualified testing bv

 

 

Van: emc-p...@ieee.org [mailto:emc-p...@ieee.org] Namens emcp...@aol.com
Verzonden: donderdag 8 april 2010 19:18
Aan: emc-p...@ieee.org
Onderwerp: Need help with EN60950 for power supply

 

Hello Group,

 

What is the effect of the 2nd Edition of EN60950 on replacement parts for
systems which are no longer in production?

 

Scenario A:

A system is certified to the 1st Edition only and installed in an EU country. 
This particular system has a failure and needs a part replaced such as a power
supply. The replacement parts are only qualified to the 1st edition also and
are stored in warehouses, (in the EU or outside the EU).  Are we allowed to
ship and install these replacements?

 

Is there a way for some one to get something little more solid then just
opinion?. Maybe some official (I have not idea who or what) agency or gov
response from EU. Or if there is any document regarding this type of topic in
EU that he/you or I can reference.

 

Regards,

Tim Pierce

 

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Need help with EN60950 for power supply

[emc-p...@ieee.org]

Hello Group,

 

What is the effect of the 2nd Edition of EN60950 on replacement parts for
systems which are no longer in production?

 

Scenario A:

A system is certified to the 1st Edition only and installed in an EU country. 
This particular system has a failure and needs a part replaced such as a power
supply. The replacement parts are only qualified to the 1st edition also and
are stored in warehouses, (in the EU or outside the EU).  Are we allowed to
ship and install these replacements?

 

Is there a way for some one to get something little more solid then just
opinion?. Maybe some official (I have not idea who or what) agency or gov
response from EU. Or if there is any document regarding this type of topic in
EU that he/you or I can reference.

 

Regards,

Tim Pierce

 

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Re: FW: EN60950-1:2001 Clause 6.2.2.2 , Test 6.2.1 c and FCC Part 68 4.3

[emc-p...@ieee.org]

On 11/20/2006, I wrote:



1000 volt impulse test of 6.2.2.2


When I meant to say "1000 volt electric strength test of 6.2.2.2."




Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com  

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Re: FW: EN60950-1:2001 Clause 6.2.2.2 , Test 6.2.1 c and FCC Part 68 4.3

[emc-p...@ieee.org]

On 11/20/2006, Kevin Harris wrote:



Could SPARK GAPS (designed as a part of the pcb layout), be removed
during the Steady-state test? 



Hi Kevin:

I think that within the context of clause 6.2.2 of EN 60950-1, you could
define a spark gap in your board layout as a "surge suppressor" and test it
accordingly.  This would require separating the spark gap from the rest of the
circuit so that each could be tested separately.

However, I think you will find that it is very difficult to pursue this
approach while complying with other requirements in EN 60950-1 and with other
goals you may have for good performance in the field.

I gather that you want to use a spark gap that will break down for the 1000
volt impulse test of 6.2.2.2.  This means that the spacing will likely be in
the range of 0.2 mm.  So, you will violate the default spacing requirements in
clause 2.3.2 and will have to work through that clause as well.  One way to do
that is to use a permanent ground on the equipment.  Without further study I
can't rule out other ways to satisfy clause 2.3.2, but without a permanent
ground you will likely have some convincing to do with your safety test lab. 
Perhaps this is why you are asking about the definition of a "component."

Another thing to keep in mind is that spark gaps formed with copper traces on
a circuit board are very unreliable.  The actual breakdown threshold will vary
over a wide range, and the copper contacts are only useful for low energy
surges such as static discharges.  Typical lightning transients will usually
melt back the electrodes and carbonize the gap area after only one or two
surges.

I realize that spark gaps formed in the board layout are seemingly attractive
because of their low cost, but they perform poorly for lightning surges.  If
you decide to use a spark gap that breaks down at less than 1000 VRMS, you
will have the additional challenges of complying with clauses 2.3.2, 6.1.2,
and 6.2.  

I know that some people use gas tubes or thyristors in precisely the same
locations that you are apparently proposing for your spark gap, and that these
components are more readily viewed as removable surge suppression devices.  I
have seen such designs gain approval even when the system has no permanent
ground connection.  While I believe this approach in ungrounded systems is
technically allowable under EN 60950-1, I do not like to use it.

So, if you can first persuade your test lab that it is okay to use gas tubes
in the locations you propose, and then you persuade them that your spark gaps
are simply an alternative suppression "component," you *might* be able to go
down this path.  However, the for the reasons stated above, I think spark gaps
in the board layout do not perform well, and I also prefer to avoid surge
suppressors connected to ground in systems that do not have a permanent ground
connection.




Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com  

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FW: EN60950-1:2001 Clause 6.2.2.2 , Test 6.2.1 c and FCC Part 68 4.3

[emc-p...@ieee.org]

 Posted for a colleague

Kevin Harris


Dear Colleagues,

Within the subject Clause it is specified that: "...for 6.2.1 c it is
permitted to remove surge suppressors, provided that..."

My questions are: 

1. Could SPARK GAPS (designed as a part of the pcb layout), be removed
during the Steady-state test? [cut and never pasted...(:-)]
(considering that it is a type test only-sacrificed board); 

2. Could a SPARK GAP be DEFINED (designed as a part of the pcb layout)
as a COMPONENT?

3. Which IEC, ISO publication offers the DEFINITION for COMPONENT?

Please accept in advance my many thanks for all of your comments! Have a
great week!

Respectfully yours,
Constantin

Constantin Bolintineanu P.Eng.
Digital Security Controls (DSC),
A Division of TYCO SAFETY PRODUCTS CANADA Ltd.
3301 LANGSTAFF Road, L4K 4L2
CONCORD, ONTARIO, CANADA
e-mail: cbolintine...@tycoint.com
Tel: 905 760 3000 ext 2568
Fax: 905 760 3020

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RE: EN60950-1 Table 5B error?

[emc-p...@ieee.org]

Thanks David and Don.  This makes sense now.

Jim Eichner, P.Eng. 
Compliance Engineering Manager
Xantrex Technology Inc. 
phone: (604) 422-2546 
fax: (604) 420-1591 
e-mail: jim.eich...@xantrex.com 
web: www.xantrex.com 
Confidentiality Notice: This email message, including any attachments,
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From: emc-p...@ieee.org  On Behalf Of David Gelfand
Sent: Wednesday, June 14, 2006 4:59 AM
To: emc-p...@ieee.org
Subject: RE: EN60950-1 Table 5B error?

Jim,

I believe the table is ok.  Table 2G note 1 points to clause 5.3.4,
requirements for functional insulation.  If you don't meet clearance and
creepage distance requirements for functional insulation, you can choose
500V electric strength test as alternate option.  Electric strength
requirements do not apply to components bridging functional isolation.  

Regards,

David.

David Gelfand, P.E.
Product Integrity Engineer
Mitec Telecom Inc
9000 Trans-Canada Highway
Pointe-Claire QC
Canada H9R 5Z8
514 694 9000 x2262



From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Jim
Eichner
Sent: 13 juin 2006 18:57
To: emc-p...@ieee.org
Subject: EN60950-1 Table 5B error?

Referring to the 2nd last column ("between independent secondary
circuits", working voltage U< 42.4Vpk), why would Functional insulation
require a 500V test but Basic/Supplemental/Reinforced have no test?  Is
this table wrong?

For components (optocoupler, SMT transformer) crossing a Functional
isolation boundary between an SELV circuit and another SELV circuit (an
ethernet circuit in this case), do I need to specify electric strength
requirements?  

Thanks,

Jim Eichner, P.Eng. 
Compliance Engineering Manager
Xantrex Technology Inc. 
e-mail: jim.eich...@xantrex.com
web: www.xantrex.com
Any opinions expressed are those of my invisible friend.
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RE: EN60950-1 Table 5B error?

[emc-p...@ieee.org]

Jim,

The table is not wrong.  The working voltages in that column are
non-hazardous, so basic, supplementary and reinforced insulation do not
apply.  The application for that column would be the use of 5.3.4 (b) for
evaluating SELV or ELV functional insulation.

Regards,

Don Gies, N.C.E
Senior Product Compliance Engineer
Lucent Technologies - Global Product Compliance Laboratory
Holmdel, NJ 07733 USA


From: Jim Eichner [mailto:jim.eich...@xantrex.com] 
Sent: Tuesday, June 13, 2006 6:57 PM
To: EMC-PSTC@listserv.ieee.org
Subject: EN60950-1 Table 5B error?

Referring to the 2nd last column ("between independent secondary
circuits", working voltage U< 42.4Vpk), why would Functional insulation
require a 500V test but Basic/Supplemental/Reinforced have no test?  Is
this table wrong?

For components (optocoupler, SMT transformer) crossing a Functional
isolation boundary between an SELV circuit and another SELV circuit (an
ethernet circuit in this case), do I need to specify electric strength
requirements?  

Thanks,

Jim Eichner, P.Eng. 
Compliance Engineering Manager
Xantrex Technology Inc. 
e-mail: jim.eich...@xantrex.com 
web: www.xantrex.com 
Any opinions expressed are those of my invisible friend.
Confidentiality Notice: This email message, including any attachments,
is for the sole use of the intended recipient(s) and may contain
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RE: EN60950-1 Table 5B error?

[emc-p...@ieee.org]

Jim,

I believe the table is ok.  Table 2G note 1 points to clause 5.3.4,
requirements for functional insulation.  If you don't meet clearance and
creepage distance requirements for functional insulation, you can choose
500V electric strength test as alternate option.  Electric strength
requirements do not apply to components bridging functional isolation.  

Regards,

David.

David Gelfand, P.E.
Product Integrity Engineer
Mitec Telecom Inc
9000 Trans-Canada Highway
Pointe-Claire QC 
Canada H9R 5Z8
514 694 9000 x2262



From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Jim
Eichner
Sent: 13 juin 2006 18:57
To: emc-p...@ieee.org
Subject: EN60950-1 Table 5B error?

Referring to the 2nd last column ("between independent secondary
circuits", working voltage U< 42.4Vpk), why would Functional insulation
require a 500V test but Basic/Supplemental/Reinforced have no test?  Is
this table wrong?

For components (optocoupler, SMT transformer) crossing a Functional
isolation boundary between an SELV circuit and another SELV circuit (an
ethernet circuit in this case), do I need to specify electric strength
requirements?  

Thanks,

Jim Eichner, P.Eng. 
Compliance Engineering Manager
Xantrex Technology Inc. 
e-mail: jim.eich...@xantrex.com
web: www.xantrex.com
Any opinions expressed are those of my invisible friend.
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is for the sole use of the intended recipient(s) and may contain
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EN60950-1 Table 5B error?

[emc-p...@ieee.org]

Referring to the 2nd last column ("between independent secondary
circuits", working voltage U< 42.4Vpk), why would Functional insulation
require a 500V test but Basic/Supplemental/Reinforced have no test?  Is
this table wrong?

For components (optocoupler, SMT transformer) crossing a Functional
isolation boundary between an SELV circuit and another SELV circuit (an
ethernet circuit in this case), do I need to specify electric strength
requirements?  

Thanks,

Jim Eichner, P.Eng. 
Compliance Engineering Manager
Xantrex Technology Inc. 
e-mail: jim.eich...@xantrex.com 
web: www.xantrex.com 
Any opinions expressed are those of my invisible friend.
Confidentiality Notice: This email message, including any attachments,
is for the sole use of the intended recipient(s) and may contain
confidential and privileged information. Any unauthorized review, use,
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RE: Insulation coordination with respect to EN60950

[emc-p...@ieee.org]

 
Vic,

I have a pdf of "The physical fundamentals of low-voltage co-ordination"
by K. Stimper of VDE.  Contact me off-line and I can forward you a copy.

Regards,

David.

David Gelfand, P.E.
Product Integrity Engineer
Mitec Telecom Inc
9000 Trans-Canada Highway
Pointe-Claire QC H9R 5Z8
Canada
514 694 9000 x2262





From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Gibling,
Vic
Sent: Friday, March 17, 2006 9:15 AM
To: emc-p...@ieee.org
Subject: Insulation coordination with respect to EN60950

Hello,

I am trying to understand some of the reasoning/philosophy behind the
values derived from EN60950 with respect to
insulation/creepage/clearance/electrical strength.

I started by attempting to read IEC 60664 but feel there must be a more
user friendly introduction available.

I would appreciate any guidance on this subject.

Thank you

Vic

Vagabond Compliance Engineer

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Insulation coordination with respect to EN60950

[emc-p...@ieee.org]

Hello,

I am trying to understand some of the reasoning/philosophy behind the values
derived from EN60950 with respect to
insulation/creepage/clearance/electrical strength.

I started by attempting to read IEC 60664 but feel there must be a more user
friendly introduction available.

I would appreciate any guidance on this subject.

Thank you

Vic

Vagabond Compliance Engineer

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VDE 0100 vs. EN60950

[owner-emc-p...@listserv.ieee.org]

Dear Group,

Does anyone have any high level info on the differences between the two
standards, looking at the basic info I've been able to find it appears that
VDE0100 is related to wiring and safety for field safety personnel.

Does anyone have any further information please ?

Many thanks

Carl

Carl Richards,
Regulatory Compliance Manager,
Aspect Communications
E-mail carl.richa...@aspect.com
Tel +44 (0)208 589 1461
Fax +44 (0)870 460 1950


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Re: EN60950 2nd edition expiring

[owner-emc-p...@listserv.ieee.org]

> Can you advise me if products made this year under the 2nd edition can still
be sold in
Europe in 2005?

Gary,

The date of cessation of presumption of conformity of the 2nd edition is
1/1/05, so presumption
of conformity can not be provided by this standard and the products can not be
put on the
market after Dec. 31, 2004. But there is an alternative path: asses your
product to determine
if you can provide evidence of conformity with the essential requirements of
the LVD (see the
LVD for details).

Regards,

John Radomski
Principal Engineer
Schneider Automation


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SV: EN60950 2nd edition expiring

[owner-emc-p...@listserv.ieee.org]

>From 01.01.2005, you have at use EN60950:2000 or newer version of the
standard.
You can not put products into the EU market after 01.01.2005, which only
fulfills EN60950:1992 ("2nd ed").

#Amund


> -Opprinnelig melding-
> Fra: owner-emc-p...@listserv.ieee.org
> [mailto:owner-emc-p...@listserv.ieee.org]Pa vegne av Tornquist, Gary
> (San Diego Safety)
> Sendt: 24. november 2004 01:41
> Til: emc-p...@ieee.org
> Emne: EN60950 2nd edition expiring
>
>
> Hello people,
> I understadn that EN60960 2nd is no longer valid after the end of this
> year.  Can you advise me if products made this year under the 2nd
> edition can still be sold in Europe in 2005?
>
> Thanks,
> Gary Tornquist
>
> 
> This message is from the IEEE Product Safety Engineering Society
> emc-pstc discussion list.Website:  http://www.ieee-pses.org/
>
> To post a message to the list, send your e-mail to emc-p...@ieee.org
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>
> All emc-pstc postings are archived and searchable on the web at:
>
> http://www.ieeecommunities.org/emc-pstc


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EN60950 2nd edition expiring

[owner-emc-p...@listserv.ieee.org]

Hello people,
I understadn that EN60960 2nd is no longer valid after the end of this
year.  Can you advise me if products made this year under the 2nd
edition can still be sold in Europe in 2005?

Thanks,
Gary Tornquist


This message is from the IEEE Product Safety Engineering Society
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RE: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium http://www.emc2004.org/
-- 
Doug,
 
UL 50 does not apply if the voltage within the outdoor enclosure is limited to
21 V. Anything over 21 V needs an NRTL Listed or specially evaluated NEMA type
enclosure with a rating depending on the environement in which the product is
subjected (ice protected for Alaska, dust protected for Arizona, etc.). The
guidelines as written today with 21 V limits comes from the NEC.
 
 
 
Regards, Peter

Doug Massey  wrote:

http://www.ieee-pses.org/symposium
http://www.emc2004.org/


Eric & Neil,

TC108 is working on IEC 60950-22, ITE Installed Outdoors, which may
hopefully put some parameters on a topic that is at present somewhat
subjective. The standard is currently in its 2nd committee draft.

In the meantime, you may want to review UL's Guideline for ITE installed
outdoors at http://www.ul.com/ite/OutdoorITEGuideline.PDF, which, as I
understand it, discusses much of the rationale that will be seen in the -22
standard, including installation category, transient protection, etc., in
addition to pollution degree.

Specifically, page 19 of this document discusses PD in relation to ingress
protection - although it does not give a specific set of rules correlating
IP rating to PD.

In! general, if you can show that an enclosure prevents the interior from
being subject to conductive pollution, or to dry non-conductive pollution
that could become conductive during periods of expected condensation, then
the evaluator can assume PD2.

In my estimation, this means that a minimum IP rating of IP54 would be
required to safely assume PD2 on the interior of an enclosure intended for
outdoor use - if the enclosure may likely be subject to hose-down, such as
mounted on the side of a residence, then IP55 would be a minimum rating - in
this particular case, where the homeowner may use a pressure washer, IP56 is
more appropriate. If the unit is to mounted near to the ground, or below
ground level, then IP57 is appropriate.

As of today, this is a subjective call - I'm not sure how much detail will
be given on this topic in the -22 standard - but I would hazard to guess
that any effort to establish a firm set of rules for a broad spec! trum of
products will result in criteria that does not allow much room to easily
apply sound engineering judgment - when you try to make a set of rules that
covers everything, the rules tend to be very strict.

A related topic that I would like to see resolved is the US national
deviation that requires manufacturers of outdoor ITE to comply with UL50
environmental protection criteria for the US and Canada, and does not allow
a cross-reference to IP ratings - this dual criteria typically doubles the
cost of enclosure testing for manufacturers of outdoor ITE, with little
objective justification.

Doug Massey, NCE



From: owner-emc-p...@listserv.ieee.org
[mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Barker, Neil
Sent: Monday, June 07, 2004 5:20 AM
To: 'intert...@safety.demon.co.uk'; emc-p...@majordomo.ieee.org
Subject: RE: Pollution Degrees EN60950 - are others struggling too !

http://www.ieee-pses.org/symposium
http://www.emc2004.org/


Eric,

I don't believe that you can correlate IP rating and Pollution Degree.
While Ingress Protection can provide some assurance of a specific pollution
degree, it can be perfectly acceptable for equipment with an IP rating of
only say IP20 to be assesses for Pollution Degree 2 if the typical usage and
the operating instructions indicate that it is suitable for use only in
specific environments such as offices. You cannot test for a specific
pollution degree, it is simply a condition that must be considered when
performing a safety assessment.

By the way, an outdoor enclosure can meet pollution degree 2. We manufacture
products that are intended to be mounted on the outside of buildings or
vehicles. The enclosure has an environmental seal and is vented through a
dessicant breather, so the interior rem! ains clean and dry.

Best regards,

Neil R. Barker C.Eng. MIEE MIEEE MSEE
Manager
Compliance Engineering
e2v technologies ltd
106 Waterhouse Lane
Chelmsford
Essex
CM1 2QU
UK

Tel: +44 (0)1245 453616
Fax: +44 (0)1245 453410
e-mail: neil.bar...@e2vtechnologies.com
Web: http://www.e2vtechnologies.com



From: intert...@safety.demon.co.uk [mailto:intert...@safety.demon.co.uk]
Sent: 01 June 2004 19:51
To: emc-p...@majordomo.ieee.org
Subject: Pollution Degrees EN60950 - are others struggling too !


http://www.ieee-pses.org/symposium
http://www.emc2004.org/


Only two replies to this one last week -
thank you guys - good supportive information.

Can I entice any further responses ?

I have IT equipment certified to EN60950 - Pollution Degree 2.
The designer swears blind that his out-door cabinet can m! eet the
requirements of Pollution Degree 2 - IT IS VERY DOUBTFUL.

Do any environmental test labs in the UK test to

RE: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Eric & Neil,

TC108 is working on IEC 60950-22, ITE Installed Outdoors, which may
hopefully put some parameters on a topic that is at present somewhat
subjective. The standard is currently in its 2nd committee draft.

In the meantime, you may want to review UL's Guideline for ITE installed
outdoors at http://www.ul.com/ite/OutdoorITEGuideline.PDF, which, as I
understand it, discusses much of the rationale that will be seen in the -22
standard, including installation category, transient protection, etc., in
addition to pollution degree.

Specifically, page 19 of this document discusses PD in relation to ingress
protection - although it does not give a specific set of rules correlating
IP rating to PD.

In general, if you can show that an enclosure prevents the interior from
being subject to conductive pollution, or to dry non-conductive pollution
that could become conductive during periods of expected condensation, then
the evaluator can assume PD2.

In my estimation, this means that a minimum IP rating of IP54 would be
required to safely assume PD2 on the interior of an enclosure intended for
outdoor use - if the enclosure may likely be subject to hose-down, such as
mounted on the side of a residence, then IP55 would be a minimum rating - in
this particular case, where the homeowner may use a pressure washer, IP56 is
more appropriate. If the unit is to mounted near to the ground, or below
ground level, then IP57 is appropriate.

As of today, this is a subjective call - I'm not sure how much detail will
be given on this topic in the -22 standard - but I would hazard to guess
that any effort to establish a firm set of rules for a broad spectrum of
products will result in criteria that does not allow much room to easily
apply sound engineering judgment - when you try to make a set of rules that
covers everything, the rules tend to be very strict.

A related topic that I would like to see resolved is the US national
deviation that requires manufacturers of outdoor ITE to comply with UL50
environmental protection criteria for the US and Canada, and does not allow
a cross-reference to IP ratings - this dual criteria typically doubles the
cost of enclosure testing for manufacturers of outdoor ITE, with little
objective justification.

Doug Massey, NCE



From: owner-emc-p...@listserv.ieee.org
[mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Barker, Neil
Sent: Monday, June 07, 2004 5:20 AM
To: 'intert...@safety.demon.co.uk'; emc-p...@majordomo.ieee.org
Subject: RE: Pollution Degrees EN60950 - are others struggling too !

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Eric,

I don't believe that you can correlate IP rating and Pollution Degree.
While Ingress Protection can provide some assurance of a specific pollution
degree, it can be perfectly acceptable for equipment with an IP rating of
only say IP20 to be assesses for Pollution Degree 2 if the typical usage and
the operating instructions indicate that it is suitable for use only in
specific environments such as offices. You cannot test for a specific
pollution degree, it is simply a condition that must be considered when
performing a safety assessment.

By the way, an outdoor enclosure can meet pollution degree 2. We manufacture
products that are intended to be mounted on the outside of buildings or
vehicles. The enclosure has an environmental seal and is vented through a
dessicant breather, so the interior remains clean and dry.

Best regards,

Neil R. Barker C.Eng. MIEE MIEEE MSEE
Manager
Compliance Engineering
e2v technologies ltd
106 Waterhouse Lane
Chelmsford
Essex
CM1 2QU
UK

Tel: +44 (0)1245 453616
Fax: +44 (0)1245 453410
e-mail: neil.bar...@e2vtechnologies.com
Web: http://www.e2vtechnologies.com



From: intert...@safety.demon.co.uk [mailto:intert...@safety.demon.co.uk]
Sent: 01 June 2004 19:51
To: emc-p...@majordomo.ieee.org
Subject: Pollution Degrees EN60950 - are others struggling too !


http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Only two replies to this one last week -
thank you guys - good supportive information.

Can I entice any further responses ?

I have IT equipment certified to EN60950 - Pollution Degree 2.
The designer swears blind that his out-door cabinet can meet the
requirements of Pollution Degree 2 - IT IS VERY DOUBTFUL.

Do any environmental test labs in the UK test to
EN60950 - Pollution Degree 2 ?

I believe they only test IP ratings - that is why I need to correlate
Pollution Degree 2 to an IP rating.

While we are at it :
Would anyone venture to correlate Pollution Degree 1 & 3
to IP ratings ?

Eric
ericm...@intertest.co.uk IEng, IIE, SEE, IIRSM
INTERTest Systems UK
the trading name of the test laboratory
of E M Consulting Ltd
Safety - Consultancy, evaluation and Int Certification



This message is from the IEEE Product Safety Engineering Society
emc-pstc discuss

RE: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Eric,

I don't believe that you can correlate IP rating and Pollution Degree.
While Ingress Protection can provide some assurance of a specific pollution
degree, it can be perfectly acceptable for equipment with an IP rating of
only say IP20 to be assesses for Pollution Degree 2 if the typical usage and
the operating instructions indicate that it is suitable for use only in
specific environments such as offices. You cannot test for a specific
pollution degree, it is simply a condition that must be considered when
performing a safety assessment.

By the way, an outdoor enclosure can meet pollution degree 2. We manufacture
products that are intended to be mounted on the outside of buildings or
vehicles. The enclosure has an environmental seal and is vented through a
dessicant breather, so the interior remains clean and dry.

Best regards,

Neil R. Barker C.Eng. MIEE MIEEE MSEE
Manager
Compliance Engineering
e2v technologies ltd
106 Waterhouse Lane
Chelmsford
Essex
CM1 2QU
UK

Tel: +44 (0)1245 453616
Fax: +44 (0)1245 453410
e-mail: neil.bar...@e2vtechnologies.com
Web: http://www.e2vtechnologies.com



From: intert...@safety.demon.co.uk [mailto:intert...@safety.demon.co.uk]
Sent: 01 June 2004 19:51
To: emc-p...@majordomo.ieee.org
Subject: Pollution Degrees EN60950 - are others struggling too !


http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Only two replies to this one last week -
thank you guys - good supportive information.

Can I entice any further responses ?

I have IT equipment certified to EN60950 - Pollution Degree 2.
The designer swears blind that his out-door cabinet can meet the
requirements of Pollution Degree 2 - IT IS VERY DOUBTFUL.

Do any environmental test labs in the UK test to
EN60950 - Pollution Degree 2 ?

I believe they only test IP ratings - that is why I need to correlate
Pollution Degree 2 to an IP rating.

While we are at it :
Would anyone venture to correlate Pollution Degree 1 & 3
to IP ratings ?

Eric
ericm...@intertest.co.uk IEng, IIE, SEE, IIRSM
INTERTest Systems UK
the trading name of the test laboratory
of E M Consulting Ltd
Safety - Consultancy, evaluation and Int Certification



This message is from the IEEE Product Safety Engineering Society
emc-pstc discussion list.

IEEE PSES Main Website:  http://www.ieee-pses.org/

To post a message send your e-mail to emc-p...@ieee.org

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RE: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


I have a 1 page summary of the IP codes/IP tests that I would be happy to
send anyone who is interested - send me an e-mail off-line if you would like
me to send you a copy. In my opinion, an IP5X could be supported as meeting
Pollution Degree II and IP6X could be supported as Pollution Degree I.

Regards,
Bill Bisenius
E.D.& D.
bi...@productsafet.com



From: intert...@safety.demon.co.uk [mailto:intert...@safety.demon.co.uk]
Sent: Tuesday, June 01, 2004 2:51 PM
To: emc-p...@majordomo.ieee.org
Subject: Pollution Degrees EN60950 - are others struggling too !


http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Only two replies to this one last week -
thank you guys - good supportive information.

Can I entice any further responses ?

I have IT equipment certified to EN60950 - Pollution Degree 2. The designer
swears blind that his out-door cabinet can meet the requirements of
Pollution Degree 2 - IT IS VERY DOUBTFUL.

Do any environmental test labs in the UK test to
EN60950 - Pollution Degree 2 ?

I believe they only test IP ratings - that is why I need to correlate
Pollution Degree 2 to an IP rating.

While we are at it :
Would anyone venture to correlate Pollution Degree 1 & 3
to IP ratings ?

Eric
ericm...@intertest.co.uk IEng, IIE, SEE, IIRSM
INTERTest Systems UK
the trading name of the test laboratory
of E M Consulting Ltd
Safety - Consultancy, evaluation and Int Certification



This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list.

IEEE PSES Main Website:  http://www.ieee-pses.org/

To post a message send your e-mail to emc-p...@ieee.org

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 Jim Bacher: j.bac...@ieee.org

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This message is from the IEEE Product Safety Engineering Society
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RE: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

This is a multi-part message in MIME format.
http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Ralph,

I couldn't agree more.

Call me different, but after reading Dr. Stimper's book, I found IEC 664
and now IEC 60664-X much more understandable and at times enjoyable.

Best regards,

-doug

Douglas E. Powell, Staff Engineer
Corporate Compliance Dept.
Advanced Energy Industries, Inc.
Fort Collins, CO 80525 USA





From: owner-emc-p...@listserv.ieee.org
[mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of Ralph McDiarmid
Sent: Friday, June 04, 2004 9:44 AM
To: emc-pstc@LISTSERV.IEEE.ORG
Subject: RE: Pollution Degrees EN60950 - are others struggling too !


http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


This document is the most interesting and informative one the topic I
have seen.  An excellent background on the topic and a nice change from
reading standards and directives.

Thanks to Mr. Nute for making it available and to Prof. Stimper for
scanning it to a pdf.

Ralph McDiarmid, AScT
Compliance Engineering Group
Xantrex Technology Inc.


> -Original Message-
> From: Rich Nute [mailto:ri...@sdd.hp.com]
> Sent: June 2, 2004 12:40 PM
> To: j...@jmwa.demon.co.uk
> Cc: doug.pow...@aei.com; intert...@safety.demon.co.uk;
> emc-pstc@LISTSERV.IEEE.ORG
> Subject: Re: Pollution Degrees EN60950 - are others struggling too !
>
>
> http://www.ieee-pses.org/symposium
>   http://www.emc2004.org/
> --
>
> >An excellent reading resource is: "The physical fundamentals of
> >low-voltage insulation co-ordination" / Klaus Stimper - Berlin;
> >Offenbach: vde-verlag. 1991.  This book is not longer available in
> >English and I contacted Mr. Stimper about this a couple
> years ago.  If
> >you can find a copy, this book explains much of the
> background to IEC
> >664 and IEC 664A.  I refer to it quite often.  If there is enough
> >interest, possibly VDE-Verlag can be convinced to publish a
> new English
> >version.
>
> Prof. Stimper was kind enough to scan the English
> version for me.
>
> The copy is comprised of two pdf files, one is 3.5+ MB,
> the other is 4.8+ MB.  In my correspondence with Prof. Stimper, he
> mentions that the English version is slightly different than the
> German version.  John Woodgate provides good advice.  :-)
>
> If you want a copy, please send e-mail.  (The material
> does not bear a copyright mark.)
>
>
> Best regards,
> Rich
>
> ---
>
> This message is from the IEEE Product Safety Engineering Society
> emc-pstc discussion list.
>
> IEEE PSES Main Website:  http://www.ieee-pses.org/
>
> To post a message send your e-mail to emc-p...@ieee.org
>
> Instructions for use of the list server:
>
http://listserv.ieee.org/listserv/request/user-guide.html

List rules: http://www.ieee-pses.org/listrules.html

For help, send mail to the list administrators:

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 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:

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This message is from the IEEE Product Safety Engineering Society
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 Jim Bacher: j.bac...@ieee.org

All emc-pstc postings are archived and searchable on the web at:

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This message is from the IEEE Product Safety Engineering Society
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IEEE PSES Main Website:  http://www.ieee-pses.org/

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All emc-pstc postings are archived and searchable on th

RE: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


This document is the most interesting and informative one the topic I have
seen.  An excellent background on the topic and a nice change from reading
standards and directives.

Thanks to Mr. Nute for making it available and to Prof. Stimper for scanning
it to a pdf.

Ralph McDiarmid, AScT
Compliance Engineering Group
Xantrex Technology Inc.


> -Original Message-
> From: Rich Nute [mailto:ri...@sdd.hp.com]
> Sent: June 2, 2004 12:40 PM
> To: j...@jmwa.demon.co.uk
> Cc: doug.pow...@aei.com; intert...@safety.demon.co.uk;
> emc-pstc@LISTSERV.IEEE.ORG
> Subject: Re: Pollution Degrees EN60950 - are others struggling too !
>
>
> http://www.ieee-pses.org/symposium
>   http://www.emc2004.org/
> --
>
> >An excellent reading resource is: "The physical fundamentals of
> >low-voltage insulation co-ordination" / Klaus Stimper - Berlin;
> >Offenbach: vde-verlag. 1991.  This book is not longer available in
> >English and I contacted Mr. Stimper about this a couple
> years ago.  If
> >you can find a copy, this book explains much of the
> background to IEC
> >664 and IEC 664A.  I refer to it quite often.  If there is enough
> >interest, possibly VDE-Verlag can be convinced to publish a
> new English
> >version.
>
> Prof. Stimper was kind enough to scan the English
> version for me.
>
> The copy is comprised of two pdf files, one is 3.5+ MB,
> the other is 4.8+ MB.  In my correspondence with Prof.
> Stimper, he mentions that the English version is slightly
> different than the German version.  John Woodgate provides
> good advice.  :-)
>
> If you want a copy, please send e-mail.  (The material
> does not bear a copyright mark.)
>
>
> Best regards,
> Rich
>
> ---
>
> This message is from the IEEE Product Safety Engineering
> Society emc-pstc discussion list.
>
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Re: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


POWELL, DOUG  wrote (in <970A8FE5DB2BE64EB6EAB84087
dcc1c8042...@bssexc01.aei.com>) about 'Pollution Degrees EN60950 - are
others struggling too !', on Wed, 2 Jun 2004:
>An excellent reading resource is: "The physical fundamentals of
>low-voltage insulation co-ordination" / Klaus Stimper - Berlin;
>Offenbach: vde-verlag. 1991.  This book is not longer available in
>English and I contacted Mr. Stimper about this a couple years ago.  If
>you can find a copy, this book explains much of the background to IEC
>664 and IEC 664A.  I refer to it quite often.  If there is enough
>interest, possibly VDE-Verlag can be convinced to publish a new English
>version.

Learn to read German instead: it's much more useful in the long term.
(;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk



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RE: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

This is a multi-part message in MIME format.
http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Eric,

I agree that Pollution Degree (PD) and Ingress Protection (IP) appear to
be very similar.  However, it is my understanding that these two are not
the same.  IP is protection from ingress of contaminants in the
macro-environment and PD is a micro-environment parameter for
calculation of dimensioning for insulation.  Certainly IP is able to
influence PD, for example, humidity influences conductivity of pollution
but it is not strictly pollution by itself.

I believe it is possible to claim PD2 or better for outdoor enclosures,
under certain conditions.  Ultimately, all buildings with electrical
equipment installed are enclosures of one sort or another and we
routinely see buildings achieve PD2 or even PD1 in a PD4 environment.  I
would think a gasketed enclosure with no negative pressure differential
would work fine.  In addition,  I don't believe it is necessary to
hermetically seal the enclosure.

Directly correlating PD to IP class or NEMA enclosures is another
problem.  Although it seems reasonable, I'm not sure that I would know
how to begin.  Whereas IP has a progressive numerical relationship from
one level to the next, PD describes different types of pollution at each
level (e.g. conductive vs. non-conductive).  Eventually, it is the
manufacturer of the product who declares the PD of the environment and
the IP of the product.  This, in turn, drives the choice of insulating
materials, dimensioning of spacings  and the possible need for coatings
on PWBs.

I should mention that I once had an experience where I thought I had a
sealed enclosure and successfully reduced PD3 down to PD2.  What I
forgot was the pressure differential from interior to exterior of the
enclosure.  The equipment had an open cable conduit routed to another
part of the factory.  The facility main heating system actually caused a
small pressure differential from one end of the building to another and
the conduit behaved much like an air supply, a dirty air supply.  I
ended up with quite a bit of pollution inside the enclosure.

An excellent reading resource is: "The physical fundamentals of
low-voltage insulation co-ordination" / Klaus Stimper - Berlin;
Offenbach: vde-verlag. 1991.  This book is not longer available in
English and I contacted Mr. Stimper about this a couple years ago.  If
you can find a copy, this book explains much of the background to IEC
664 and IEC 664A.  I refer to it quite often.  If there is enough
interest, possibly VDE-Verlag can be convinced to publish a new English
version.

Regards,

-doug


Douglas E. Powell, Staff Engineer
Corporate Compliance Dept.
Advanced Energy Industries, Inc.
Fort Collins, CO 80525 USA







From: owner-emc-p...@listserv.ieee.org
[mailto:owner-emc-p...@listserv.ieee.org] On Behalf Of
intert...@safety.demon.co.uk
Sent: Tuesday, June 01, 2004 12:51 PM
To: emc-p...@majordomo.ieee.org
Subject: Pollution Degrees EN60950 - are others struggling too !


http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Only two replies to this one last week -
thank you guys - good supportive information.

Can I entice any further responses ?

I have IT equipment certified to EN60950 - Pollution Degree 2. The
designer swears blind that his out-door cabinet can meet the
requirements of Pollution Degree 2 - IT IS VERY DOUBTFUL.

Do any environmental test labs in the UK test to
EN60950 - Pollution Degree 2 ?

I believe they only test IP ratings - that is why I need to correlate
Pollution Degree 2 to an IP rating.

While we are at it :
Would anyone venture to correlate Pollution Degree 1 & 3
to IP ratings ?

Eric
ericm...@intertest.co.uk IEng, IIE, SEE, IIRSM
INTERTest Systems UK
the trading name of the test laboratory
of E M Consulting Ltd
Safety - Consultancy, evaluation and Int Certification



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Lis

Re: Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


intert...@safety.demon.co.uk wrote (in <40BCDE06.1535.53BCAF@localhost>)
about 'Pollution Degrees EN60950 - are others struggling too !', on Tue,
1 Jun 2004:
>I have IT equipment certified to EN60950 - Pollution Degree 2.
>The designer swears blind that his out-door cabinet can meet the
>requirements of Pollution Degree 2 - IT IS VERY DOUBTFUL.


Pollution degrees are neither defined in IEC/EN 60950-1 or referenced to
a standard in which they are defined. This should be remedied; a
reference to one of TC109's standards is probably called for
>
>Do any environmental test labs in the UK test to
>EN60950 - Pollution Degree 2 ?
>
>I believe they only test IP ratings - that is why I need to correlate
>Pollution Degree 2 to an IP rating.
>
>While we are at it :
>Would anyone venture to correlate Pollution Degree 1 & 3
>to IP ratings ?

Degree 1 might be achieved inside an IP67 box filled with dry air or
inert gas. Degree 3 involves condensation, so it could occur anywhere
that normal air is present.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk



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Pollution Degrees EN60950 - are others struggling too !

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Only two replies to this one last week -
thank you guys - good supportive information.

Can I entice any further responses ?

I have IT equipment certified to EN60950 - Pollution Degree 2.
The designer swears blind that his out-door cabinet can meet the
requirements of Pollution Degree 2 - IT IS VERY DOUBTFUL.

Do any environmental test labs in the UK test to
EN60950 - Pollution Degree 2 ?

I believe they only test IP ratings - that is why I need to correlate
Pollution Degree 2 to an IP rating.

While we are at it :
Would anyone venture to correlate Pollution Degree 1 & 3
to IP ratings ?

Eric
ericm...@intertest.co.uk IEng, IIE, SEE, IIRSM
INTERTest Systems UK
the trading name of the test laboratory
of E M Consulting Ltd
Safety - Consultancy, evaluation and Int Certification



This message is from the IEEE Product Safety Engineering Society
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RE: Pollution degrees EN60950

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium http://www.emc2004.org/
-- 

I have a few minutes until my test unit ends with a glorious death... 

Source: Conformity Magazine 
The majority of internal 
office use equipment is given the 
classification of pollution degree 2. 
This is characterized as an area in 
which only non-conductive pollution 
normally occurs. Occasionally a 
temporary conductivity caused by 
condensation can be expected. 
Unless outdoor equipment is designed 
with a filtering system that limits the 
pollutants to that of level 2, the 
pollution degree 3 classification is 
assumed. Pollution degree 3 denotes 
an internal environment that is subject 
to conductive pollution or to dry, nonconductive 
pollution that could 
become conductive due to 
condensation. The increased 
likelihood of conductive debris 
bridging the insulation gap translates 
into a requirement for increased 
clearance and creepage distances. 

Source: DIN VDE 0110 part 1, page 4 
Only non-conductive pollution occurs. Occasional temporary conducting as a
result of condensation. 

Most Important Sources: IEC 60664, Insulation Coordination for Equipment
within Low-Voltage Systems; and IEC 60529, degrees of Protection Provided by
Enclosures

"IP XY" 
X - protection against ingress of solid objects 
Y - protection against ingress of water 

IMO, the first "characteristic numeral" should be at least "5", because this
is the the lowest level indicated by 60529 that dust penetration quantity will
not "impair safety". BUT, in a hostile enviroment, "6" would probably be
required to maintain PD2. Also, this would allow conformance to 60950-1,
clause 2.10.7 for application of PD1 for all enviroments; and where the
distances for Table 2L "go away".

luck, 
Brian 



(if you do not have 60529, look at www.
ubersuhner.com/mozilla/products/hs-p-rf/hs-p-rf-info/hs-p-rf-info-ip and
www.lighting4sport.com/iprating.htm

-Original Message- 
From: EMC-PSTC [ mailto:emc-p...@hypercom.com] 
Sent: Friday, May 28, 2004 7:18 AM 
To: emc-p...@ieee.org 
Subject: Pollution degrees EN60950 

Hi. 

Here's an easy one for Friday. 

What is the current interpretation on "Pollution Degree 2" 
when compared to the IP** table. 

I'm struggling with a borderline case and need to end my week 
happy ! 

Eric 

--- 

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RE: Pollution degrees EN60950

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Eric,

While Pollution Degrees and IP ratings cannot be directly correlated, I
would suggest that Pollution Degree 2 could apply up to and including IP54,
but obviously depends on the intended use environment. Above IP54 you may be
able to claim Pollution Degree 1, providing there is no breathing of the
enclosure.

Best regards,

Neil R. Barker C.Eng. MIEE MIEEE MSEE
Manager
Compliance Engineering
e2v technologies ltd
106 Waterhouse Lane
Chelmsford
Essex
CM1 2QU
UK

Tel: +44 (0)1245 453616
Fax: +44 (0)1245 453410
e-mail: neil.bar...@e2vtechnologies.com
Web: http://www.e2vtechnologies.com


Hi.

Here's an easy one for Friday.

What is the current interpretation on "Pollution Degree 2"
when compared to the IP** table.

I'm struggling with a borderline case and need to end my week
happy !

Eric
ericm...@intertest.co.uk IEng, IIE, SEE, IIRSM
INTERTest Systems UK
the trading name of the test laboratory
of E M Consulting Ltd
Safety - Consultancy, evaluation and Int Certification



This message is from the IEEE Product Safety Engineering Society
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Pollution degrees EN60950

[owner-emc-p...@listserv.ieee.org]

http://www.ieee-pses.org/symposium
  http://www.emc2004.org/




  ericm...@napit.in
  fo   To:  
emc-p...@majordomo.ieee.org
   cc:
  05/28/2004 06:23 Subject:  Pollution degrees
EN60950
  AM






http://www.ieee-pses.org/symposium
  http://www.emc2004.org/


Hi.

Here's an easy one for Friday.

What is the current interpretation on "Pollution Degree 2"
when compared to the IP** table.

I'm struggling with a borderline case and need to end my week
happy !

Eric
ericm...@intertest.co.uk IEng, IIE, SEE, IIRSM
INTERTest Systems UK
the trading name of the test laboratory
of E M Consulting Ltd
Safety - Consultancy, evaluation and Int Certification



This message is from the IEEE Product Safety Engineering Society
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Re: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Here is a link to one vendor's IEC 309 type plugs and sockets. Scroll 
down toward the bottom for photos.

http://www.schneider-electric.co.th/product/powerplug.htm

Scott Douglas, NCE



Richard Hughes wrote:

>Joe,
>
>You asked...
>
>Joe Randolph wrote:
>
> > Hi Richard:
> >
>
> >
> > I do have one remaining question.  You mention that EN60309 describes
> > pluggable Type B sockets.  I do not have a copy of EN60309.  It is true
> > that the standard AC mains plugs commonly used on home and office ITE
> > products are completely incompatible with the ones defined in EN60309?
> > I would just like to know if there is any opportunity for a manufacturer
> > to argue that the plug on their standard office ITE product is actually
> > intended for a Type B socket.
> >
> > Thanks again for your help with sorting all this out.
> >
>
>REH> IEC/EN 60309 is a standard that covers industrial mains plugs, 
>mains sockets and industrial couplers.  If you ever see one of the plugs 
>or sockets you would understand why it is impossible to fit an ordinary 
>domestic plug (certainly and European or US plug that I'm familiar with) 
>by accident, or even foreseeable misuse, into an IEC/EN 60309 socket. 
>So there is no opportunity for a manufacturer to argue that the domestic 
>plug fitted to the cord of their standard office ICT product is actually 
>intended for a Type B socket
>
>
> >
> > Joe Randolph
> > Telecom Design Consultant
> > Randolph Telecom, Inc.
> > 781-721-2848 (USA)
> > j...@randolph-telecom.com
> > http://www.randolph-telecom.com
> >
> >
>
>
>---
>This message is from the IEEE EMC Society Product Safety
>Technical Committee emc-pstc discussion list.
>
>Visit our web site at:  http://www.ieee-pses.org/
>
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>
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>http://www.ieeecommunities.org/emc-pstc
>
>
>  
>




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RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Joe,

You asked...

Joe Randolph wrote:

 > Hi Richard:
 >

 >
 > I do have one remaining question.  You mention that EN60309 describes
 > pluggable Type B sockets.  I do not have a copy of EN60309.  It is true
 > that the standard AC mains plugs commonly used on home and office ITE
 > products are completely incompatible with the ones defined in EN60309?
 > I would just like to know if there is any opportunity for a manufacturer
 > to argue that the plug on their standard office ITE product is actually
 > intended for a Type B socket.
 >
 > Thanks again for your help with sorting all this out.
 >

REH> IEC/EN 60309 is a standard that covers industrial mains plugs, 
mains sockets and industrial couplers.  If you ever see one of the plugs 
or sockets you would understand why it is impossible to fit an ordinary 
domestic plug (certainly and European or US plug that I'm familiar with) 
by accident, or even foreseeable misuse, into an IEC/EN 60309 socket. 
So there is no opportunity for a manufacturer to argue that the domestic 
plug fitted to the cord of their standard office ICT product is actually 
intended for a Type B socket


 >
 > Joe Randolph
 > Telecom Design Consultant
 > Randolph Telecom, Inc.
 > 781-721-2848 (USA)
 > j...@randolph-telecom.com
 > http://www.randolph-telecom.com
 >
 >



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 Richard Nute:   ri...@ieee.org
 Jim Bacher: j.bac...@ieee.org

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http://www.ieeecommunities.org/emc-pstc

RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Hi Richard:

Thanks for yet another detailed description regarding aspects of this
confusing topic.

My conclusion from all this discussion is that the only practical
difference between the 6.1.2.2 text in the main body of EN 60950-1 and
the text in Annex ZB is that for Finland, Norway, and Sweden, equipment
that uses a permanently connected earthing conductor must be installed
by a service person.  The text in the main body leaves open the
possibility that the protective earthing conductor could be installed by
the user.  I don't know why they couldn't state the difference more
simply.

A related conclusion is that for "typical" office equipment, surge
protectors from tip/ring to ground must have a minimum breakover of 400
volts in Finland, Norway, and Sweden unless the equipment is intended to
be installed by a service person.

I do have one remaining question.  You mention that EN60309 describes
pluggable Type B sockets.  I do not have a copy of EN60309.  It is true
that the standard AC mains plugs commonly used on home and office ITE
products are completely incompatible with the ones defined in EN60309?
I would just like to know if there is any opportunity for a manufacturer
to argue that the plug on their standard office ITE product is actually
intended for a Type B socket.

Thanks again for your help with sorting all this out.
 
 
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com


> -Original Message-
> From: owner-emc-p...@majordomo.ieee.org 
> [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Richard Hughes
> Sent: Friday, January 09, 2004 9:47 AM
> To: Joe Randolph
> Cc: emc-p...@majordomo.ieee.org
> Subject: RE: EN60950-1,TNV to Earth Insulation
> 
> 
> 
> Joe,
> 
> Following fast on the heals of my earlier reply, you can perhaps 
> understand that equipment that is professionally installed is 
> expected 
> to be earthed if required (otherwise the installer could hardly be 
> called 'professional'!).
> 
> Similarly,  it is expected that an industrial socket to EN60309 
> (pluggable Type B) will be installed so that its earth connection is 
> connected to the building's earth.
> 
> Point 3 is for the Central Office of telecoms centres.  
> Again, in such 
> premises it is expected that a 'proper' earth connection will be 
> available.  For equipment powered from station office 
> batteries, this is 
>   generally a sub-set of 1.
> 
> Point 4 is not applicable in Europe, as can be seen by looking at EN 
> 60950-1 clause 6.1.2.2, where you will see that it has been 
> removed as a 
> Common Modification. Basically, it is considered that a label on the 
> equipment telling the user to get the equipment 
> professionally installed 
> does not provide an adequate degree of safety (due to the 
> likelihood of 
> such a notice being disregarded).
> 
> I hope that this is now the end of this topic, but if not I'm 
> more than 
> happy to provide PAID consultation!!!
> 
> Regards,
> 
> Richard Hughes
> www.safetyanswers.ltd.uk
> 
> 
> 
> Joe Randolph wrote:
> 
>  >
>  > In a posting dated 1/8/2004, I wrote:
>  >
>  > > Now I go to Annex ZB and look at the deviations to 
> clause  > > 6.1.2.2 for Finland, Norway, and Sweden.  The 
> exclusions  > > described here are much more restrictive, 
> limited to  > > permanently connected equipment or pluggable 
> equipment type  > > B, used in restricted access locations 
> where equipotential  > > bonding has been applied.  In other 
> words, a telephone  > > central office or *maybe* the main 
> telephone closet in an  > > office building.  Certainly, no 
> stretch of the imagination  > > would have this clause 
> include the typical office environment.  >  >  > Hello All:  
> >  > Okay, I re-read the wording of the Annex ZB deviation to 
> clause 6.1.2.2  > of EN 60950-1, and I think I have developed 
> a partial answer to my own  > question.  I see that I missed 
> the word "and" in one place and perhaps  > misinterpreted the 
> meaning of "and" in a second place.  After reading  > the 
> clause carefully several times, I think it is saying that 
> exclusions  > are available for four separate cases:  >  > 1) 
> Permanently connected equipment.  >  > 2) Pluggable equipment 
> Type B.  >  > 3) Equipment used in a restricted access 
> location that has equipotential  > bonding.  >  > 4) 
> Equipment that has provisions for a permanently connected 
> protective  > earthing conductor and is provided with 
> instructions for installation 

RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

In a message dated 1/9/2004, Richard Hughes writes:

> I hope that I have explained why the insulation is for a Primary
Circuit 
> rather than for a Secondary Circuit (as could be expected because a
TNV 
> Circuit is a Secondary Circuit).


Hi Richard:

Thanks for your detailed description.  As it turns out, I have heard
variations of this rationale before.  In fact, what we now think of as a
"Nordic" requirement used to appear in the UK safety standard BS 6301
back in the 1980s.  A fellow at BT offered a similar (but not identical)
rationale when I inquired about it at the time.  The same requirement
was included in the initial "harmonized" telecom safety standard EN
41003, and at least one edition of that standard actually contained an
explanatory note that summarized the rationale.

However, I think the discussion has drifted from the original question,
which had to do with interpreting what the latest requirements in EN
60950-1 call for.  Under the latest version of Annex ZB there is no need
to debate whether the supplementary insulation should be for a primary
circuit or a secondary circuit, because there is no reference whatsoever
to supplementary insulation.  All that remains is a list of specific
requirements on solid insulation.

There is only one remaining place in the standard where it is necessary
to decide whether the TNV insulation is for a primary circuit or a
secondary circuit.  That occurs in clause 2.3.2 where there is a
reference to basic insulation.  In this case the applicable requirements
are those for a secondary circuit.

As Ron Pickard noted in an earlier posting, the current edition still
leaves room for people to have debates (as they have for years) about
the assigned working voltage for the basic insulation referenced in
clause 2.3.2.  I avoided commenting on this earlier because I did not
want to open another can of worms.  

For what it's worth, the conservative interpretation that I have been
persuaded to use says the working voltage for a generic, unspecified
TNV-3 PSTN line is 120 volts (max TNV) plus the SELV voltage on the
other side of the barrier.  This yields a range of 120 to 180 volts,
depending on the characteristics of the SELV circuit.  So, for
compliance with the basic insulation requirement in clause 2.3.2, we
have a working voltage (subject to debate) and we know that the
applicable tables are those for a secondary circuit (not subject to
debate, as far as I know).



Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com



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RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Joe,

Following fast on the heals of my earlier reply, you can perhaps 
understand that equipment that is professionally installed is expected 
to be earthed if required (otherwise the installer could hardly be 
called 'professional'!).

Similarly,  it is expected that an industrial socket to EN60309 
(pluggable Type B) will be installed so that its earth connection is 
connected to the building's earth.

Point 3 is for the Central Office of telecoms centres.  Again, in such 
premises it is expected that a 'proper' earth connection will be 
available.  For equipment powered from station office batteries, this is 
  generally a sub-set of 1.

Point 4 is not applicable in Europe, as can be seen by looking at EN 
60950-1 clause 6.1.2.2, where you will see that it has been removed as a 
Common Modification. Basically, it is considered that a label on the 
equipment telling the user to get the equipment professionally installed 
does not provide an adequate degree of safety (due to the likelihood of 
such a notice being disregarded).

I hope that this is now the end of this topic, but if not I'm more than 
happy to provide PAID consultation!!!

Regards,

Richard Hughes
www.safetyanswers.ltd.uk



Joe Randolph wrote:

 >
 > In a posting dated 1/8/2004, I wrote:
 >
 > > Now I go to Annex ZB and look at the deviations to clause
 > > 6.1.2.2 for Finland, Norway, and Sweden.  The exclusions
 > > described here are much more restrictive, limited to
 > > permanently connected equipment or pluggable equipment type
 > > B, used in restricted access locations where equipotential
 > > bonding has been applied.  In other words, a telephone
 > > central office or *maybe* the main telephone closet in an
 > > office building.  Certainly, no stretch of the imagination
 > > would have this clause include the typical office environment.
 >
 >
 > Hello All:
 >
 > Okay, I re-read the wording of the Annex ZB deviation to clause 6.1.2.2
 > of EN 60950-1, and I think I have developed a partial answer to my own
 > question.  I see that I missed the word "and" in one place and perhaps
 > misinterpreted the meaning of "and" in a second place.  After reading
 > the clause carefully several times, I think it is saying that exclusions
 > are available for four separate cases:
 >
 > 1) Permanently connected equipment.
 >
 > 2) Pluggable equipment Type B.
 >
 > 3) Equipment used in a restricted access location that has equipotential
 > bonding.
 >
 > 4) Equipment that has provisions for a permanently connected protective
 > earthing conductor and is provided with instructions for installation of
 > that conductor by a service person.
 >
 >
 > In the wording of Annex ZB, note that the "and" between cases 3 and 4
 > could be interpreted to be merging them into a single case, rather than
 > establishing case 4 as a standalone case.
 >
 > So, the liberal interpretation is that case 4 is a viable, standalone
 > option, similar to the 6.1.2.2 text in the main body of the standard
 > except for the specific reference to having a service person install the
 > ground conductor.  Even with the reference to the service person, this
 > case provides enough wiggle room to allow the equipment to be used in a
 > normal office environment.
 >
 > The conservative interpretation merges cases 3 and 4 into a single case
 > and pretty much excludes the normal office environment if the AC mains
 > connector is pluggable Type A.
 >
 > I'm still interested to know what other list members think this means
 > for the case I described in my earlier posting.
 >
 >
 >
 > Joe Randolph
 > Telecom Design Consultant
 > Randolph Telecom, Inc.
 > 781-721-2848 (USA)
 > j...@randolph-telecom.com
 > http://www.randolph-telecom.com
 >
 >
 >
 > ---
 > This message is from the IEEE EMC Society Product Safety
 > Technical Committee emc-pstc discussion list.
 >
 > Visit our web site at:  http://www.ieee-pses.org/
 >
 > To cancel your subscription, send mail to:
 >  majord...@ieee.org
 > with the single line:
 >  unsubscribe emc-pstc
 >
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 >  Ron Pickard:  emc-p...@hypercom.com
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 >  Jim Bacher: j.bac...@ieee.org
 >
 > All emc-pstc postings are archived and searchable on the web at:
 > http://www.ieeecommunities.org/emc-pstc
 >




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RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Joe,

So you want to know more about the Nordic deviations regarding EN 
60950-1, well sit yourself down and get a mug of coffee as I explain the 
reasons behind these deviations…

In Scandinavia (we are told in the IEC by representatives from the 
countries mentioned in the deviations) it is common to find socket 
outlets that have an earth connection that is in fact not connected. 
Now, it has also been discussed that other countries have this situation 
too, but they have chosen not to adopt the same deviations as the 
Scandinavian countries [if you consider that this applies in your 
country and think that something should be done about it, then please 
contact your national committee].

Most equipment only has Basic Insulation between the Primary Circuit and 
Protective Earth and also has Y capacitors connected across this Basic 
Insulation.  Now, you may think that this situation is questionable from 
a safety perspective, but it is referred to as a Class 0 installation. 
In the vicinity of the equipment everything is (supposed to be) earth 
free and so if you were to bridge between a such a part and a part that 
is connected to the mains by Y caps (i.e. anything connected to the 
Protective Earth connection of most ICT equipment) then no current (or 
only a small, depending on the insulation resistance) would flow and so 
you would not get an electric shock.

Now consider a telecommunications system.  It can, and is, touched by 
network engineers far removed from the customer’s premises.  These 
engineers can be earthed and so it is important that they are 
effectively protected from parts that are only separated from the 
Primary Circuit by Basic Insulation.  Following the classic approach, it 
should now be easy to see where the original requirement for 
Supplementary Insulation came from and why this was for a Primary 
Circuit and not a Secondary Circuit.

Given that the ac mains supply has a tolerance of 10% and the peak of 
the ac mains is 1.414 times the rms value, we have a combined 
magnification factor of 1.5554, or 1.6 to be a bit on the safe side.  A 
device, whether it be a gas tube or a semiconductor device, rated 300Vdc 
will break down when the mains is applied to it and so it will not 
protect the network engineer in the situation as described above.  Of 
course, all devices have a tolerance and that is why the standard 
defines the MINIMUM value: it is for the manufacturer to choose a rated 
value and tolerance that will not break down when the mains is applied 
to it.

I hope that I have explained why the insulation is for a Primary Circuit 
rather than for a Secondary Circuit (as could be expected because a TNV 
Circuit is a Secondary Circuit).

Regards,

Richard Hughes

Safety Answers Limited
www.safetyanswers.ltd.uk






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RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Hi Joe,
If you have unbalanced protection only, i.e. a surge protector between tip
and ring, then the conduction voltage for the device can be down as low as
270V, which is dictataed by the functional requirements of the  circuit
rather than safety. For functional reasons, sometimes you have to have a
ground reference on the interface, so you have to usea balanced protection
scheme. If you have balanced protection, ie a surge protector between tip
and ground (T-G) , ring and ground (R-G), and tip to ring(T-R), AND you
don't have a permanently connected protective earth, then the T-G, and R-G
surge devices have to be 1.6 times the rated voltage, i.e. for 240V rated
the conduction voltage must be 400V. Obviously the T-R device does not have
to meet that requirement. As a bonus it turned out that the 400V devices
were the same price as the 300V devices. (Note: the surge protectors I am
talking about are semiconductor type, not gas discharge).

Regards

Doug



  

  "Joe Randolph"  

  , 
  com>  
 
   
  Sent by: cc:

  owner-emc-pstc@majordo   Subject:  RE: EN60950-1,TNV
to Earth Insulation 
  mo.ieee.org 

  

  

  01/09/04 01:50 AM   

  Please respond to "Joe  

  Randolph"   

  

  





In a message dated 1/8/2004, Peter Merguerian writes:

> There should be no problem to find min. 400 V surge protectors - they are
readily available

> I am sure that the fax, modems, PBXs out there which have been certified
are mounted with
> surge protectors with a breakover voltage of 1.6 Vrated of the equipment.


Hi Peter:

Actually, in the cases I referenced, the protection devices were in the
range of 300 volts.  This seems to be fairly common.  I think the typical
reason is that the designers were simply not aware of the 1.6x requirement,
so they chose breakdown voltages based on the maximum ringing voltage.

I know it is easy to get gas tubes with minimum breakdowns of over 400
volts, but semiconductor devices such as sidactors are not typically
available with such high voltage ratings.  I have seen several designs that
used a 3-terminal sidactor with a minimum breakdown in the range of 270
volts.

In my own designs, I avoid putting protection devices from TNV-3 to ground
unless it is absolutely necessary, such as on a FXS-type feed circuit that
must supply ground referenced DC feed and ringing.  For the typical
FXO-type interfaces used in terminal devices like modems and fax machines,
I only put breakdown devices across tip/ring, and then I rely on a good
isolation barrier for protection from surges between tip/ring and ground.

The reason for my original posting was simply that I am curious about all
the products I have seen that had sub-400 volt protection devices from
tip/ring to ground and also had no provisions for a permanent earth
connection.  Either these designs are slipping through the safety approval
process by mistake, or I am misinterpreting clause 6.1.2.1.

It sounds as though you would agree that any such designs must have slipped
through the safety approval process by mistake.


Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com






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Technical Committee emc-pstc discussion list.

Visit our web site at:  http://www.ieee-pses.or

RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

In a message dated 1/8/2004, Peter Merguerian writes: 
 
> There should be no problem to find min. 400 V surge protectors - they are
readily available 
 
> I am sure that the fax, modems, PBXs out there which have been certified are
mounted with 
> surge protectors with a breakover voltage of 1.6 Vrated of the equipment. 
 
 
Hi Peter:
 
Actually, in the cases I referenced, the protection devices were in the range
of 300 volts.  This seems to be fairly common.  I think the typical reason is
that the designers were simply not aware of the 1.6x requirement, so they
chose breakdown voltages based on the maximum ringing voltage.
 
I know it is easy to get gas tubes with minimum breakdowns of over 400 volts,
but semiconductor devices such as sidactors are not typically available with
such high voltage ratings.  I have seen several designs that used a 3-terminal
sidactor with a minimum breakdown in the range of 270 volts.
 
In my own designs, I avoid putting protection devices from TNV-3 to ground
unless it is absolutely necessary, such as on a FXS-type feed circuit that
must supply ground referenced DC feed and ringing.  For the typical FXO-type
interfaces used in terminal devices like modems and fax machines, I only put
breakdown devices across tip/ring, and then I rely on a good isolation barrier
for protection from surges between tip/ring and ground.
 
The reason for my original posting was simply that I am curious about all the
products I have seen that had sub-400 volt protection devices from tip/ring to
ground and also had no provisions for a permanent earth connection.  Either
these designs are slipping through the safety approval process by mistake, or
I am misinterpreting clause 6.1.2.1.
 
It sounds as though you would agree that any such designs must have slipped
through the safety approval process by mistake.
 
 
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com

RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Joe,
 
There should be no problem to find min. 400 V surge protectors - they are
readily available. I recently had this problem with a manufacturer of an
office appliance and they were able to find a similar surge protector rated
for the higher breakover voltage. 
 
If you need to locate a source for min. 400 V breakover surge protectors,
please let me know. 
 
I am sure that the fax, modems, PBXs out there which have been certified are
mounted with surge protectors with a breakover voltage of 1.6 Vrated of the
equipment. 
 
 
Best Regards,
 
Peter

Joe Randolph  wrote:


Hello All:

While we are on the subject of TNV-to-earth insulation, I would like to
pose a related question regarding clause 6.1.2.1 in EN 60950-1 and the
deviations in Annex ZB for Finland, Sweden, and Norway. This question
relates to the requirement that "surge suppressors that bridge the
insulation shall have a minimum breakover voltage of 1.6 times the rated
voltage.". 

Suppose I have a piece of office equipment that is powered from the AC
mains and has a rated voltage of 250 VRMS. The equipment also has a
connection to a TNV-3 phone line. It uses a 3-wire AC mains plug that
includes an earth ground. 

Inside the equipment, the surge protection on the TNV-3 phone line
includes two 300 volt surge protectors, connected from tip to ground and
>from ring to ground (there is a third surge protector connected across
tip! and ring, but that is incidental to the question at hand). I have
seen this type of construction many times, and I believe it is widely
used in the industry.

Now, if I evaluate this construction for compliance with clause 6.1.2.1,
I quickly conclude that the two surge protectors connected tip-to-ground
and ring-to-ground must have a minimum breakover voltage of no less than
(1.6)x(250) = 400 volts. 

Okay, this looks like a problem, but the exclusions in clause 6.1.2.2
leave some wiggle room. This particular piece of office equipment is
not permanently connected, nor is it installed by a service person.
However, it is possible to equip it with provisions for a permanent
earthing conductor and then provide instructions for the installation of
that conductor. Never mind how many users will actually read the
instructions

Now I go to Annex ZB and look at the deviations to clause 6.1.2.2 for
Finland, Norway, and Sweden. The exclusions described here are much
more restrictive, limited to permanently connected equipment or
pluggable equipment type B, used in restricted access locations where
equipotential bonding has been applied. In other words, a telephone
central office or *maybe* the main telephone closet in an office
building. Certainly, no stretch of the imagination would have this
clause include the typical office environment.

So, does this equipment fail to comply with EN 60950-1 for use in
Finland, Norway, and Sweden? It appears to me that it fails to comply,
but I can tell you there is a lot of product out there that meets this
description. Think modems, fax machines, and small PBXs.

I would like to hear what others in the group think. Am I missing
something here?


Thanks,

Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com



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RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

In a posting dated 1/8/2004, I wrote:

> Now I go to Annex ZB and look at the deviations to clause 
> 6.1.2.2 for Finland, Norway, and Sweden.  The exclusions 
> described here are much more restrictive, limited to 
> permanently connected equipment or pluggable equipment type 
> B, used in restricted access locations where equipotential 
> bonding has been applied.  In other words, a telephone 
> central office or *maybe* the main telephone closet in an 
> office building.  Certainly, no stretch of the imagination 
> would have this clause include the typical office environment.


Hello All:

Okay, I re-read the wording of the Annex ZB deviation to clause 6.1.2.2
of EN 60950-1, and I think I have developed a partial answer to my own
question.  I see that I missed the word "and" in one place and perhaps
misinterpreted the meaning of "and" in a second place.  After reading
the clause carefully several times, I think it is saying that exclusions
are available for four separate cases:

1) Permanently connected equipment.

2) Pluggable equipment Type B.

3) Equipment used in a restricted access location that has equipotential
bonding.

4) Equipment that has provisions for a permanently connected protective
earthing conductor and is provided with instructions for installation of
that conductor by a service person.


In the wording of Annex ZB, note that the "and" between cases 3 and 4
could be interpreted to be merging them into a single case, rather than
establishing case 4 as a standalone case.

So, the liberal interpretation is that case 4 is a viable, standalone
option, similar to the 6.1.2.2 text in the main body of the standard
except for the specific reference to having a service person install the
ground conductor.  Even with the reference to the service person, this
case provides enough wiggle room to allow the equipment to be used in a
normal office environment.

The conservative interpretation merges cases 3 and 4 into a single case
and pretty much excludes the normal office environment if the AC mains
connector is pluggable Type A.

I'm still interested to know what other list members think this means
for the case I described in my earlier posting.


 
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com




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RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Hello All:

While we are on the subject of TNV-to-earth insulation, I would like to
pose a related question regarding clause 6.1.2.1 in EN 60950-1 and the
deviations in Annex ZB for Finland, Sweden, and Norway.  This question
relates to the requirement that "surge suppressors that bridge the
insulation shall have a minimum breakover voltage of 1.6 times the rated
voltage.".  

Suppose I have a piece of office equipment that is powered from the AC
mains and has a rated voltage of 250 VRMS.  The equipment also has a
connection to a TNV-3 phone line.  It uses a 3-wire AC mains plug that
includes an earth ground.  

Inside the equipment, the surge protection on the TNV-3 phone line
includes two 300 volt surge protectors, connected from tip to ground and
>from ring to ground (there is a third surge protector connected across
tip and ring, but that is incidental to the question at hand).  I have
seen this type of construction many times, and I believe it is widely
used in the industry.

Now, if I evaluate this construction for compliance with clause 6.1.2.1,
I quickly conclude that the two surge protectors connected tip-to-ground
and ring-to-ground must have a minimum breakover voltage of no less than
(1.6)x(250) = 400 volts.  

Okay, this looks like a problem, but the exclusions in clause 6.1.2.2
leave some wiggle room.  This particular piece of office equipment is
not permanently connected, nor is it installed by a service person.
However, it is possible to equip it with provisions for a permanent
earthing conductor and then provide instructions for the installation of
that conductor.  Never mind how many users will actually read the
instructions

Now I go to Annex ZB and look at the deviations to clause 6.1.2.2 for
Finland, Norway, and Sweden.  The exclusions described here are much
more restrictive, limited to permanently connected equipment or
pluggable equipment type B, used in restricted access locations where
equipotential bonding has been applied.  In other words, a telephone
central office or *maybe* the main telephone closet in an office
building.  Certainly, no stretch of the imagination would have this
clause include the typical office environment.

So, does this equipment fail to comply with EN 60950-1 for use in
Finland, Norway, and Sweden?  It appears to me that it fails to comply,
but I can tell you there is a lot of product out there that meets this
description.  Think modems, fax machines, and small PBXs.

I would like to hear what others in the group think.  Am I missing
something here?


Thanks,

Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com



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RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Richard,

>REH> It is my belief that the dielectric withstand test is that required
>for basic insulation for a PRIMARY circuit, not a SECONDARY circuit -
>although I agree the requirement is not as clear as it could be.
>REH> If you look at   Annex ZB it tells you to "add the following text
>between the first and second paragraph", part of the text being "each of
>which shall pass the electric strength test below" and the second para
>has the text "insulation shall have a minimum d.c. sparkover voltage of
>1,6 times the RATED VOLTAGE or 1,6 times the upper voltage of the RATED
>VOLTAGE RANGE of the equipment"

The "1.6 x RATED VOLTAGE" requirement goes back to at least IEC950:1991
(6.3.3.1) where basic
insulation was required and I presume for a secondary circuit as it doesn't
specifically state that.
The primary circuit requirement came from Annex ZB (6.2.1.2), which was
specifically stated,
therefore leading one to believe that it would a secondary circuit normally.
Unfortunately, it is
not stated in EN60950-1 one way or the other, so I believe that it will be
left to interpretation
(and many a heated argument, I suspect). Actually, if a primary circuit is
applied, then this change
in the standard is all a matter of semantics (a rose by any other name is
still a rose). So,
treating it as a primary circuit, technically nothing changes from earlier
standards (its just
described differently). But, if its treated as a secondary circuit, creepages
and clearances will
likely be reduced.

But, is it for a secondary circuit or a primary circuit? That is the question.
I would say that its
a secondary circuit, but that's only my opinion, or interpretation.

>REH> The dielectric strength requirements have been increased by a
>factor of 1.6x.

Yes, according to Annex ZB (6.1.2.1), this 1.6x (2400Vac or 3394Vdc)
dielectric test applies only to
solid insulation of semiconductor components. Thinking about it, this new 1.6x
dielectric test
requirement may force some semiconductor bridging component sourcing changes
for manufacturers.

OK, its clear (well, sort of). Basic insulation is now required, but with
supplementary insulation
features (basimentary insulation, if you will :->), given Annex ZB (6.1.2.1)
of EN60950-1.

Comments?

Best regards,

Ron Pickard
rpick...@hypercom.com


  

  richhug...@aol.co   

  mTo:  
j...@randolph-telecom.com  
   
   cc:  
rpick...@hypercom.com, emc-p...@majordomo.ieee.org        
   
  01/08/2004 02:21 Subject:  RE: EN60950-1,TNV to
Earth Insulation 
  PM  

  

  



Ron,

Joe Randolph wrote:

 > Hi Ron:
 >
 > In my interpretation of EN 60950-1, the insulation requirement is the
 > one contained in the main body of the text, UNLESS it is modified in
 > Annex ZB.  In that case, the modifications called out in Annex ZB also
 > apply.

REH> Pretty much, except more precisely the requirements of Annex ZB
replace any conflicting requirements in the body of the standard in
Finland, Norway and Sweden (in this particular case).

 >
 > So, there has in fact been a relaxation of the traditional Nordic
 > requirement for supplementary insulation.  The revised Annex ZB retains
 > only the solid insulation aspects of supplementary insulation.  The
 > creepage, clearance, and electric strength requirements are now the ones
 > in the main body of the document, namely, basic insulation for a
 > secondary circuit.

REH> It is my belief that the dielectric withstand test is that required
for basic insulation for a PRIMARY circuit, not a SECONDARY circuit -
although I agree the requirement is not as clear as it could be.
REH> If you look at   Annex ZB it tells you to "add the following text
between the first and second paragraph", part of the text being "each of
which shall pass the electric strength test below" and the second para
has the text "insulation shall have a minimum d.c. sparkover voltage of
1,6 times the 

RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

In a messaged date 1/8/2004, Richard Hughes writes:

> It is my belief that the dielectric withstand test is that required 
> for basic insulation for a PRIMARY circuit, not a SECONDARY circuit - 
> although I agree the requirement is not as clear as it could be.
> If you look at   Annex ZB it tells you to "add the following text 
> between the first and second paragraph", part of the text being "each
of 
> which shall pass the electric strength test below" and the second para

> has the text "insulation shall have a minimum d.c. sparkover voltage
of 
> 1,6 times the RATED VOLTAGE or 1,6 times the upper voltage of the
RATED 
> VOLTAGE RANGE of the equipment"

> The dielectric strength requirements have been increased by a 
> factor of 1.6x.



Hi Richard:

It appears that we are in agreement on most points except the one
excerpted above.  I think the problem is that the wording in Annex ZB is
very poor and can be interpreted different ways.  

I interpret the Annex ZB reference to "the electric strength test below"
to be pointing to the values listed in the main body text of clause
6.1.2.1, namely, a test voltage of 1500 VRMS for installations where the
AC mains voltages exceeds 130 VRMS and a test voltage of 1000 VRMS
elsewhere.  I do not think that ordinary solid insulation has to be
tested to 1.6 times 1500 VRMS.

After laying out the requirement for ordinary solid insulation, Annex ZB
goes on to describe three special cases where alternate requirements can
be applied to the solid insulation:

1) A "semiconductor component" such as an opto isolator
2) A Y2 cap
3) A Y3 cap

The reference to a test of 1.6 times 1500 VRMS is for the first of these
special cases, "semiconductor components."

Just to make things more confusing, the main body text in clause 6.1.2.1
uses the same factor of 1.6 in a different context.  The statement that
surge suppressors must have a minimum sparkover of 1.6 times the RATED
VOLTAGE is referring to the nominal AC mains voltage, not the test
voltage for electric strength.  The RATED VOLTAGE is defined in clause
1.2.1.1 and would likely be about 250 VRMS for a product used in
Finland, Norway, or Sweden that is powered from the AC mains.

The other topic where we may not completely agree is the question of
whether the applicable requirement is for a primary circuit or a
secondary circuit.  I would argue that for the purposes of clause
6.1.2.1 this question is now moot, since there is no longer any
reference in clause 6.1.2.1 to a requirement where one first needs to
determine whether the circuit is a primary circuit or a secondary
circuit.

The place where this distinction still needs to be considered is the
basic insulation requirement in clause 2.3.2.  In this case the barrier
is between (SELV or TNV-1 or accessible parts) and (TNV-2 or TNV-3).  A
TNV circuit is considered to be a secondary circuit, so Table 2K applies
instead of Table 2H.

 
 
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com


> -Original Message-
> From: owner-emc-p...@majordomo.ieee.org 
> [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Richard Hughes
> Sent: Thursday, January 08, 2004 4:22 PM
> To: j...@randolph-telecom.com
> Cc: 'Ron Pickard'; emc-p...@majordomo.ieee.org
> Subject: RE: EN60950-1,TNV to Earth Insulation
> 
> 
> 
> Ron,
> 
> 
> 
> Joe Randolph wrote:
> 
>  > Hi Ron:
>  >
>  > In my interpretation of EN 60950-1, the insulation 
> requirement is the  > one contained in the main body of the 
> text, UNLESS it is modified in  > Annex ZB.  In that case, 
> the modifications called out in Annex ZB also  > apply.
> 
> REH> Pretty much, except more precisely the requirements of Annex ZB
> replace any conflicting requirements in the body of the standard in 
> Finland, Norway and Sweden (in this particular case).
> 
>  >
>  > So, there has in fact been a relaxation of the traditional 
> Nordic  > requirement for supplementary insulation.  The 
> revised Annex ZB retains  > only the solid insulation aspects 
> of supplementary insulation.  The  > creepage, clearance, and 
> electric strength requirements are now the ones  > in the 
> main body of the document, namely, basic insulation for a  > 
> secondary circuit.
> 
> REH> It is my belief that the dielectric withstand test is 
> that required
> for basic insulation for a PRIMARY circuit, not a SECONDARY circuit - 
> although I agree the requirement is not as clear as it could be.
> REH> If you look at   Annex ZB it tells you to "add the 
> following text 
> between the first and second paragraph", part of the text 
> being "each of 
> which sh

RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Ron,



Joe Randolph wrote:

 > Hi Ron:
 >
 > In my interpretation of EN 60950-1, the insulation requirement is the
 > one contained in the main body of the text, UNLESS it is modified in
 > Annex ZB.  In that case, the modifications called out in Annex ZB also
 > apply.

REH> Pretty much, except more precisely the requirements of Annex ZB 
replace any conflicting requirements in the body of the standard in 
Finland, Norway and Sweden (in this particular case).

 >
 > So, there has in fact been a relaxation of the traditional Nordic
 > requirement for supplementary insulation.  The revised Annex ZB retains
 > only the solid insulation aspects of supplementary insulation.  The
 > creepage, clearance, and electric strength requirements are now the ones
 > in the main body of the document, namely, basic insulation for a
 > secondary circuit.

REH> It is my belief that the dielectric withstand test is that required 
for basic insulation for a PRIMARY circuit, not a SECONDARY circuit - 
although I agree the requirement is not as clear as it could be.
REH> If you look at   Annex ZB it tells you to "add the following text 
between the first and second paragraph", part of the text being "each of 
which shall pass the electric strength test below" and the second para 
has the text "insulation shall have a minimum d.c. sparkover voltage of 
1,6 times the RATED VOLTAGE or 1,6 times the upper voltage of the RATED 
VOLTAGE RANGE of the equipment"
REH> That the requirement is for a PRIMARY circuit is also logical, 
given  the origional requirement for SUPLIMENTARY insulation for a 
PRIMARY circuit and an understanding of the Nordic concerns.


 >
 > Note that while this might lead you to conclude that the electric
 > strength requirement has been relaxed from the 1500 VRMS of
 > supplementary insulation, the 1500 VRMS requirement now appears in
 > clause 6.1.2.1 for cases where the AC mains voltage exceeds 130 VRMS.
 > This change (an increase from the previous requirement of 1000 VRMS)
 > took place when the 3rd edition of EN 60950 was issued in the year 2000.
 > That same edition was the first time the reference to supplementary
 > insulation disappeared from Annex ZB.
 >
 > You ask whether the solid insulation requirements in Annex ZB apply to
 > printed wiring boards.  In my interpretation they certainly do.  In
 > earlier versions of Annex ZB that explicitly called out supplementary
 > insulation, there was always the option of using the various printed
 > circuit board construction methods that now appear in clause 2.10.5.3 of
 > EN 60950-1 (these options have appeared in earlier editions in different
 > clauses).  Now that Annex ZB makes no explicit reference to
 > supplementary insulation, some people might argue that the options
 > described in clause 2.10.5.3 can not be used.  I think these options can
 > still be used, but doing so might require some additional justification
 > to show that the result complies with the "2 thin layers" option in
 > Annex ZB.
 >
REH> Yes, the solid insulation requirements would apply to most pcbs 
with the proviso's mentioned by Joe.

 > In summary, the net effect of the changes for Finland, Norway, and
 > Sweden is that the creepage and clearance requirements have been
 > relaxed, but the requirements for solid insulation and electric strength
 > remain the same as they were when the requirement called out
 > supplementary insulation.

REH> The dielectric strength requirements have been increased by a 
factor of 1.6x.

 >
 > By the way, I have formed the impression that the reason for the
 > difference between the IEC version and the EU version is that there have
 > been ongoing efforts to get the Nordic countries to drop their
 > insistence on supplementary insulation and harmonize their requirement
 > with the rest of the EU (and in fact, the rest of the countries
 > worldwide that base their requirements on IEC 60950).  I think the
 > difference that we see is the result of a compromise that was worked out
 > between the time that the IEC version was completed and the time that
 > the EU version was published.
 >
REH> True
 >
 >
 > Joe Randolph
 > Telecom Design Consultant
 > Randolph Telecom, Inc.
 > 781-721-2848 (USA)
 > j...@randolph-telecom.com
 > http://www.randolph-telecom.com
 >
 >
 > > -Original Message-----
 > > From: owner-emc-p...@majordomo.ieee.org
 > > [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Ron Pickard
 > > Sent: Wednesday, January 07, 2004 4:38 PM
 > > To: richhug...@aol.com
 > > Cc: emc-p...@majordomo.ieee.org
 > > Subject: Re: EN60950-1,TNV to Earth Insulation
 > >
 > >
 > >
 > >
 > > Hi Richard,
 > >
 > >

RE: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Hi Ron:

In my interpretation of EN 60950-1, the insulation requirement is the
one contained in the main body of the text, UNLESS it is modified in
Annex ZB.  In that case, the modifications called out in Annex ZB also
apply.

So, there has in fact been a relaxation of the traditional Nordic
requirement for supplementary insulation.  The revised Annex ZB retains
only the solid insulation aspects of supplementary insulation.  The
creepage, clearance, and electric strength requirements are now the ones
in the main body of the document, namely, basic insulation for a
secondary circuit.

Note that while this might lead you to conclude that the electric
strength requirement has been relaxed from the 1500 VRMS of
supplementary insulation, the 1500 VRMS requirement now appears in
clause 6.1.2.1 for cases where the AC mains voltage exceeds 130 VRMS.
This change (an increase from the previous requirement of 1000 VRMS)
took place when the 3rd edition of EN 60950 was issued in the year 2000.
That same edition was the first time the reference to supplementary
insulation disappeared from Annex ZB.

You ask whether the solid insulation requirements in Annex ZB apply to
printed wiring boards.  In my interpretation they certainly do.  In
earlier versions of Annex ZB that explicitly called out supplementary
insulation, there was always the option of using the various printed
circuit board construction methods that now appear in clause 2.10.5.3 of
EN 60950-1 (these options have appeared in earlier editions in different
clauses).  Now that Annex ZB makes no explicit reference to
supplementary insulation, some people might argue that the options
described in clause 2.10.5.3 can not be used.  I think these options can
still be used, but doing so might require some additional justification
to show that the result complies with the "2 thin layers" option in
Annex ZB.

In summary, the net effect of the changes for Finland, Norway, and
Sweden is that the creepage and clearance requirements have been
relaxed, but the requirements for solid insulation and electric strength
remain the same as they were when the requirement called out
supplementary insulation.

By the way, I have formed the impression that the reason for the
difference between the IEC version and the EU version is that there have
been ongoing efforts to get the Nordic countries to drop their
insistence on supplementary insulation and harmonize their requirement
with the rest of the EU (and in fact, the rest of the countries
worldwide that base their requirements on IEC 60950).  I think the
difference that we see is the result of a compromise that was worked out
between the time that the IEC version was completed and the time that
the EU version was published.

 
 
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848 (USA)
j...@randolph-telecom.com
http://www.randolph-telecom.com


> -Original Message-
> From: owner-emc-p...@majordomo.ieee.org 
> [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Ron Pickard
> Sent: Wednesday, January 07, 2004 4:38 PM
> To: richhug...@aol.com
> Cc: emc-p...@majordomo.ieee.org
> Subject: Re: EN60950-1,TNV to Earth Insulation
> 
> 
> 
> 
> Hi Richard,
> 
> Thanks for your detailed response. However, Annex ZB 
> (6.1.2.1) only pertains to insulation that is solid or forms 
> part of a semiconductor component, to Y2 capacitors and to Y3 
> capacitors with conditions. Is the reference to solid 
> insulation meant to include printed wiring boards? If not, 
> then basic insulation for a secondary circuit is all that's 
> required now. So, basically (please excuse the pun), the only 
> missing part of the TNV-SELV insulation equation would be the 
> working voltage across the barrier. Is this a fair assessment?
> 
> Best regards,
> 
> Ron Pickard
> rpick...@hypercom.com
> 
> 
>   
>   
>
>   richhug...@aol.co   
>   
>
>   mTo:   
> rpick...@hypercom.com 
> 
>cc:   
> emc-p...@majordomo.ieee.org   
> 
>   01/07/2004 01

Re: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Hi Richard,

Thanks for your detailed response. However, Annex ZB (6.1.2.1) only pertains
to insulation that is
solid or forms part of a semiconductor component, to Y2 capacitors and to Y3
capacitors with
conditions. Is the reference to solid insulation meant to include printed
wiring boards? If not,
then basic insulation for a secondary circuit is all that's required now. So,
basically (please
excuse the pun), the only missing part of the TNV-SELV insulation equation
would be the working
voltage across the barrier. Is this a fair assessment?

Best regards,

Ron Pickard
rpick...@hypercom.com


  

  richhug...@aol.co   

  mTo:   rpick...@hypercom.com

   cc:  
emc-p...@majordomo.ieee.org   
   
  01/07/2004 01:34 Subject:  Re: EN60950-1,TNV to
Earth Insulation 
  PM  

  

  




Ron,

When you look at "in some countries" notes in IEC standards you will see
that they have all disappeared when it comes to CENELEC standards
(unless the publishing organisation hasn't done its job correctly).
The reason for this is because European deviations are relocated to
Annex ZB or Annex ZC and all non-European deviations are just stripped
out all together.

Annex ZB contain what is known as "Special National Conditions".  As the
term implies, they are applicable in some countries only (i.e. not
across the whole of Europe - such things are called "Common
Modifications") and they result from characteristic (e.g. the local
environment) or practice (commonly building wiring regulations /
national electric codes) that cannot be changed even over a long
period.  Look here and this is where you will find the deviations for
Finland, Norway and Sweden that relate to clause 6.1.2.1.


Annex ZC contain what is known as "A-deviations".  Typically these stem
>from national laws.  You will see that there is a Note that states that
  "it is the view of the Commission of the European Communities ... that
compliance with A-deviations is no longer mandatory and that the free
movement of products complying with such a standard should not be
restricted except under the safeguard procedure provided for in the
relevant Directive". Of course, if a company chooses to ignore these
deviations and is prosecuted for failure to comply with some national
law or other, the opinion of the European Commission may be moot.

But what of Annex ZA?  That is just a list of standards that have been
Normatively referred to (they must be met, where they are specifically
called up) where the references to international publications have been
replaced by their relevant European counterparts.

Now to your specific question...

Is supplementary insulation for a primary circuit still required in
order to comply with clause 6.1.2.1?

Short Answer, NO.

Detailed Answer, See Annex ZB (Page 252 if you have BS EN 60950-1).

Best regards,

Richard Hughes

Safety Answers Ltd
www.safetyanswers.ltd.uk





Ron Pickard wrote:

 >
 > To all those knowledgeable with the 60950 series of safety standards,
 >
 > I've just been able to receive my copy of EN60950-1 (I've had IEC
 > 60950-1 for some time now). Upon
 > leafing thru EN60950-1, I noticed something missing that was in notes
 > 1 & 2 of clause 6.1.2.1 of
 > IEC60950 3rd Ed. That being, the requirement for supplementary
 > insulation for a primary circuit for
 > Norway and Sweden from TNV to earth. And looking into IEC60950-1, the
 > note in clause 6.1.2.1 states
 > "In Finland, Norway and Sweden, there are additional requirements for
 > the insulation."
 > Unfortunately, I've looked in clauses 2.3, 2.9, 2.10 and 6.1, but
 > cannot find these additional
 > requirements (even the CB Bulletin appears to provide only solid
 > insulation requirements for
 > 6.1.2.1). And to make this matter a bit more obtuse, both notes in
 > clause 6.1.2.1 has been deleted
 > from EN60950-1 according to Annex NA.
 >
 > So I h

Re: EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

Ron,

When you look at "in some countries" notes in IEC standards you will see 
that they have all disappeared when it comes to CENELEC standards 
(unless the publishing organisation hasn't done its job correctly). 
The reason for this is because European deviations are relocated to 
Annex ZB or Annex ZC and all non-European deviations are just stripped 
out all together.

Annex ZB contain what is known as "Special National Conditions".  As the 
term implies, they are applicable in some countries only (i.e. not 
across the whole of Europe - such things are called "Common 
Modifications") and they result from characteristic (e.g. the local 
environment) or practice (commonly building wiring regulations / 
national electric codes) that cannot be changed even over a long
period.  Look here and this is where you will find the deviations for 
Finland, Norway and Sweden that relate to clause 6.1.2.1.


Annex ZC contain what is known as "A-deviations".  Typically these stem 
>from national laws.  You will see that there is a Note that states that 
  "it is the view of the Commission of the European Communities ... that 
compliance with A-deviations is no longer mandatory and that the free 
movement of products complying with such a standard should not be 
restricted except under the safeguard procedure provided for in the 
relevant Directive". Of course, if a company chooses to ignore these 
deviations and is prosecuted for failure to comply with some national 
law or other, the opinion of the European Commission may be moot.

But what of Annex ZA?  That is just a list of standards that have been 
Normatively referred to (they must be met, where they are specifically 
called up) where the references to international publications have been 
replaced by their relevant European counterparts.

Now to your specific question...

Is supplementary insulation for a primary circuit still required in 
order to comply with clause 6.1.2.1?

Short Answer, NO.

Detailed Answer, See Annex ZB (Page 252 if you have BS EN 60950-1).

Best regards,

Richard Hughes

Safety Answers Ltd
www.safetyanswers.ltd.uk





Ron Pickard wrote:

 >
 > To all those knowledgeable with the 60950 series of safety standards,
 >
 > I've just been able to receive my copy of EN60950-1 (I've had IEC
 > 60950-1 for some time now). Upon
 > leafing thru EN60950-1, I noticed something missing that was in notes
 > 1 & 2 of clause 6.1.2.1 of
 > IEC60950 3rd Ed. That being, the requirement for supplementary
 > insulation for a primary circuit for
 > Norway and Sweden from TNV to earth. And looking into IEC60950-1, the
 > note in clause 6.1.2.1 states
 > "In Finland, Norway and Sweden, there are additional requirements for
 > the insulation."
 > Unfortunately, I've looked in clauses 2.3, 2.9, 2.10 and 6.1, but
 > cannot find these additional
 > requirements (even the CB Bulletin appears to provide only solid
 > insulation requirements for
 > 6.1.2.1). And to make this matter a bit more obtuse, both notes in
 > clause 6.1.2.1 has been deleted
 > from EN60950-1 according to Annex NA.
 >
 > So I have to ask, is supplementary insulation for a primary
 > circuit still required here? If so,
 > where is the requirement actually stated? Or, is supplementary
 > insulation for a secondary circuit,
 > or even basic insulation, now acceptable for Norway and Sweden?
 >
 > Or, have I overlooked something? I'm trying get thru the cobwebs back
 > to daylight and I'm hoping
 > that you will help me and maybe others with the same question(s).
 >
 > I look forward to your replies. Please advise.
 >
 > Best regards,
 >
 > Ron Pickard
 > rpick...@hypercom.com
 >
 >
 >
 >
 > ---
 > This message is from the IEEE EMC Society Product Safety
 > Technical Committee emc-pstc discussion list.
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Fo

EN60950-1,TNV to Earth Insulation

[owner-emc-p...@majordomo.ieee.org]

To all those knowledgeable with the 60950 series of safety standards,

I've just been able to receive my copy of EN60950-1 (I've had IEC 60950-1 for
some time now). Upon
leafing thru EN60950-1, I noticed something missing that was in notes 1 & 2 of
clause 6.1.2.1 of
IEC60950 3rd Ed. That being, the requirement for supplementary insulation for
a primary circuit for
Norway and Sweden from TNV to earth. And looking into IEC60950-1, the note in
clause 6.1.2.1 states
"In Finland, Norway and Sweden, there are additional requirements for the
insulation."
Unfortunately, I've looked in clauses 2.3, 2.9, 2.10 and 6.1, but cannot find
these additional
requirements (even the CB Bulletin appears to provide only solid insulation
requirements for
6.1.2.1). And to make this matter a bit more obtuse, both notes in clause
6.1.2.1 has been deleted
>from EN60950-1 according to Annex NA.

So I have to ask, is supplementary insulation for a primary circuit still
required here? If so,
where is the requirement actually stated? Or, is supplementary insulation for
a secondary circuit,
or even basic insulation, now acceptable for Norway and Sweden?

Or, have I overlooked something? I'm trying get thru the cobwebs back to
daylight and I'm hoping
that you will help me and maybe others with the same question(s).

I look forward to your replies. Please advise.

Best regards,

Ron Pickard
rpick...@hypercom.com





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Re: Last day of manufacture EN60950: A4, A11

[richhug...@aol.com]

Ilan,

The "date of cessation" as given in the Official Journal of the European
Communities is not the last date for modifications but the last date on which
a statement of compliance to a particular version of a standard offers a
presumption of compliance with the safety objectives of the LVD (and the
essential requirements of the R&TTED, where applicable).

If a manufacturer wishes to base their compliance with the LVD or R&TTED on
the fact that they comply with a certain version of a Harmonised Standard
(EN60950 +A1 +A2 +A3 + A4 + A11 in your case) then the "date of cessation"
effectively becomes last date of manufacture.  

Beyond the "date of cessation" the manufacturer either has to declare
compliance with the safety objectives [essential requirements: R&TTED]
directly or they will have had to have had their product evaluated against a
more recent version of the standard: they will also have had to update their
Declaration of Conformity and Technical File accordingly.

Regards,

Richard Hughes

Safety Answers Ltd.

Re: Last day of manufacture EN60950: A4, A11

[John Woodgate]

I read in !emc-pstc that Ilan Cohen  wrote (in
<2D1037012914D4118DB8204C4F4F502045FE06@ITLLTD01>) about 'Last day of
manufacture EN60950: A4, A11' on Sun, 27 Jul 2003:
>Can anyone point me to the specified last day of manufacture for 
>products tested under EN60950: A4 and A11. (In the official Journal you 
>may find the date of 1/08/03 as the last date for modifications, but the 
>last date for manufacture is not listed) 
>
>I will be very thankful if any one actually points to the official 
>document that specifies the date.

The DOCOPOCOSS for a specific standard is given (normally) in the next
edition, in this case that is EN 60950:2000. The 'dow' given there is
2005-01-01, and the Commission has not, AFAIK, notified a different
DOCOPOCOSS.

BUT, there is also EN60950-1:2002, which can be used now and in which
the 'dow' of EN 60950:2000 is given as 2006-07-01. You may find it
advantageous to use this standard rather than the 2000 edition.

DOCOPOCOSS - date of cessation of presumption of compliance of the
superseded standard.
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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Last day of manufacture EN60950: A4, A11

[Ilan Cohen]

Can anyone point me to the specified last day of manufacture for products
tested under EN60950: A4 and A11.
(In the official Journal you may find the date of 1/08/03 as the last date
for modifications, but the last date for manufacture is not listed)

I will be very thankful if any one actually points to the official document
that specifies the date.

Thanks



Ilan Cohen
Technical Director, Safety & Telecom Divisions
I.T.L (PRODUCT TESTING) Ltd.
26 Hacharoshet St, POB 211, Or Yehuda, Israel.
Tel 972-3-5339022, Fax 972-3-5339019
ico...@itl.co.il, website: http://www.itl.co.il 



I-SPEC: The best place on the internet to learn about safety !!
http://www.i-spec.com/
(I-Spec is provided free of charge as a service by ITL to the compliance
community) 





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RE: reinforced insulation - EN60950

[Peter L. Tarver]

Alexandru -

You have received several good answers.  I would add the
following.

To Rich Nute's descriptor of "active devices," add,
"nonlinear devices," to those types of components not
acceptable for use in place of insulation.  This would
expand the scope to include gas tube and other voltage surge
suppressors, fuses and the like.

Keep in mind that Double Insulation can be achieved by two
separate pieces (or collections) of insulation.  For
instance, one transformer provides Basic Insulation and
another Supplementary Insulation.  Since you claim to have
ELV, there is the presumption that you have at least Basic
Insulation from Primary and Hazardous Voltage circuits.
Addition of a second bit of Basic Insulation gets you close
to your goal, but not quite.  If you can demonstrate that
either or both of the two bits of Basic Insulation also
comply with the additional requirements for Supplementary
Insulation, then you've achieved your goal, since Double
Insulation is equivalent to Reinforced Insulation.

If you wish to take transients into account for reduction of
Clearance Distances, you may refer to §2.10.3 and Annex G.
This doesn't work for Creepage Distances.


Regards,

Peter L. Tarver, PE
Product Safety Manager
Sanmina-SCI Homologation Services
San Jose, CA
peter.tar...@sanmina-sci.com


> -Original Message-
> From: Alexandru Guidea
> Sent: Tuesday, May 06, 2003 9:47 AM
>
> Dear colleagues,
>
> As part of a PCB design required to be compliant
> with EN60950, we want to
> use the configuration described below, to be able
> to relax the traces
> separation. The circuit intended to become SELV
> is accessible to the
> operator.
>
> Questions:
> 1. Is the combination of Basic Insulation +
> Fuse&Transorb(15V) equivalent to
> Reinforced Insulation?
> 2. Does the transorb have to comply with a
> specific EN safety standard (like
> one applicable to Y caps)?
>
> Thanks,
>
> Alexandru Guidea
>
> CAE Inc.
> Canada
>
> Basic
>  Insulation
> |
> |
> ELV||---FUSE--SELV (??)
> |  T
> |  R
>A
>N
>S
>O
>R
>B
> |
> |
>   GND (EARTH)



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Re: reinforced insulation - EN60950

[douglas_beckw...@mitel.com]

Alexandru,
The short answer is no, the circuit would not provide the equivalent of
reinforced insulation. However, have a look at 2.2.4  (60950-2000)-
Connection of SELV circuits to other circuits. You can connect SELV
circuits to other circuits provided, that under single fault conditions
(i.e. the transzorb, or fuse shorted out) you do not exceed the SELV
limits, and you have a minimum of basic insulation between SELV circuits
and the primary circuit (including the neutral).

Regards

Doug


  
  
Alexandru Guidea  
  
 To:
"'emc-p...@majordomo.ieee.org'"
Sent by: cc:  
  
owner-emc-pstc@majordom  Subject: reinforced
insulation - EN60950
o.ieee.org
  
  
  
  
  
05/06/03 12:46 PM 
  
Please respond to 
  
Alexandru Guidea  
  
  
  
  
  





Dear colleagues,

As part of a PCB design required to be compliant with EN60950, we want to
use the configuration described below, to be able to relax the traces
separation. The circuit intended to become SELV is accessible to the
operator.

Questions:
1. Is the combination of Basic Insulation + Fuse&Transorb(15V) equivalent
to
Reinforced Insulation?
2. Does the transorb have to comply with a specific EN safety standard
(like
one applicable to Y caps)?

Thanks,

Alexandru Guidea

CAE Inc.
Canada





Basic
 Insulation
|
|
ELV||---FUSE--SELV (??)
|  T
|  R
   A
   N
   S
   O
   R
   B
|
|
  GND (EARTH)





This message is from the IEEE EMC Society Product Safety
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Re: reinforced insulation - EN60950

[Rich Nute]

Hi Alexandru:


>   1. Is the combination of Basic Insulation + Fuse&Transorb(15V) equivalent
to
>   Reinforced Insulation?

No.

The scheme of protection against electric shock relies on
passive devices, not active devices.

As a general rule, active devices, e.g., transorb, are not 
allowed as equivalent to one element of a two-safeguard 
scheme, i.e., basic insulation and supplementary insulation.

For example, a GFCI/RCCB/ELCB could not be used as a 
substitute for supplementary insulation because it is an
active device.

Active schemes are permitted where additional enviromental
conditions may exist that could bypass either or both Basic 
Insulation and Supplementary Insulation (or Reinforced 
Insulation).  For example, GFCI/RCCB/ELCB is required for 
environments might be wet, where that wetness could bypass
the insulation.

Another general rule is that deliberate operation of a fuse
is not permitted.  (I do not have the rationale for this
rule.)

(Your characterization of "Basic Insulation + Fuse & Transorb"
as equivalent to "Reinforced Insulation" is incorrect.  
Reinforced Insulation is defined as a single, robust insulation 
equivalent to Double Insulation.  The fact that your scheme
includes Basic Insulation as an element means that the system
cannot be Reinforced Insulation.  A better characterization 
would be equivalent to Double Insulation.)

>   2. Does the transorb have to comply with a specific EN safety standard
(like
>   one applicable to Y caps)?

Yes, if one exists.

In the situation you describe, the transorb must be able to
dissipate the full mains voltage and current, where the 
current is the circuit prospective current, for the maximum
duration of the fuse, and still be operative for the next
such event.  

Additionally, the transorb would need to dissipate the mains
current at a current just below the fuse operating point, and 
do so indefinitely.  

And, there would be additional requirements.


Best regards,
Rich







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Listserver delays -- Re: reinforced insulation - EN60950

[Rich Nute]

>   Strange behavior of the list-server. Although I got some out-of-office
>   replies, neither I or my fellows in the office (members of the list) have
>   received the message posted 24 h ago. I'll try again...

We are still experiencing delivery problems from
the listserver.  The IEEE gurus are at work trying
to solve the problem.  We thought it had been 
solved last week, but we're still experiencing
difficulties.

Basically, the difficulties show up as very late
delivery (and occasional duplicate delivery) to the 
subscribers near the end of the list (which includes
me).  Very late can mean DAYS late.

Normal time for delivery to the full subscriber list
is 3-4 hours.  Messages are sent in sequence to the
subscriber address list, where long-time subscribers
near the head of the list get their messages first,
and so forth through the address list.

At the moment, it appears that subscribers near the
head of the list have normal service.  However,
subscribers near the end of the list (~700 and above,
which would be those who subscribed in the past year
or so) are experiencing significant delays, more than 
24 hours.

If the subscribers near the head of the list set their
mailer with an Out Of Office message, then that message
is sent immediately to the person posting the message.
For posters near the end of the list, the OOO message 
will be received BEFORE the listserver message.  (Indeed, 
this is the case even when the listserver is operating 
normally.)

Please bear with us while we solve the problem.

If you have further questions or comments, please send
them directly to me or any of the administrators at 
the bottom of this message.


Best regards,
Rich


Richard Nute
IEEE emc-pstc Listserver Administrator
ri...@ieee.org








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RE: reinforced insulation - EN60950

[richwo...@tycoint.com]

Alex, consult section 2.3.5 of EN 60950:1992 which specifies the conditions
under which SELV can be connected to other circuits including ELV.

Richard Woods
Sensormatic Electronics
Tyco International



From: Alexandru Guidea [mailto:gui...@cae.com]
Sent: Tuesday, May 06, 2003 6:47 PM
To: 'emc-p...@majordomo.ieee.org'
Subject: reinforced insulation - EN60950



Dear colleagues,

As part of a PCB design required to be compliant with EN60950, we want to
use the configuration described below, to be able to relax the traces
separation. The circuit intended to become SELV is accessible to the
operator.

Questions:
1. Is the combination of Basic Insulation + Fuse&Transorb(15V) equivalent to
Reinforced Insulation?
2. Does the transorb have to comply with a specific EN safety standard (like
one applicable to Y caps)?

Thanks,

Alexandru Guidea

CAE Inc.
Canada





Basic
 Insulation
|
|
ELV||---FUSE--SELV (??)
|  T
|  R
   A
   N
   S
   O
   R
   B
|
|
  GND (EARTH)





This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.

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RE: reinforced insulation - EN60950

[Ilan Cohen]

Alex

1) This configuration will not be acceptable for reinforced insulation. But
(depends on the application) you may have other ways to bypass the need for
reinforced insulation. 

2) The transorb is not going to be any good for you since it does not solve
your lack of insulation problem


Ilan Cohen
Technical Director, Safety & Telecom Divisions
I.T.L (PRODUCT TESTING) Ltd.
26 Hacharoshet St, POB 211, Or Yehuda, Israel.
Tel 972-3-5339022, Fax 972-3-5339019
ico...@itl.co.il, website: http://www.itl.co.il 





From: Alexandru Guidea [mailto:gui...@cae.com]
Sent: Tuesday, May 06, 2003 6:47 PM
To: 'emc-p...@majordomo.ieee.org'
Subject: reinforced insulation - EN60950



Dear colleagues,

As part of a PCB design required to be compliant with EN60950, we want to
use the configuration described below, to be able to relax the traces
separation. The circuit intended to become SELV is accessible to the
operator.

Questions:
1. Is the combination of Basic Insulation + Fuse&Transorb(15V) equivalent to
Reinforced Insulation?
2. Does the transorb have to comply with a specific EN safety standard (like
one applicable to Y caps)?

Thanks,

Alexandru Guidea

CAE Inc.
Canada





Basic
 Insulation
|
|
ELV||---FUSE--SELV (??)
|  T
|  R
   A
   N
   S
   O
   R
   B
|
|
  GND (EARTH)





This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.

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reinforced insulation - EN60950

[Alexandru Guidea]

Dear colleagues,

As part of a PCB design required to be compliant with EN60950, we want to
use the configuration described below, to be able to relax the traces
separation. The circuit intended to become SELV is accessible to the
operator.

Questions:
1. Is the combination of Basic Insulation + Fuse&Transorb(15V) equivalent to
Reinforced Insulation?
2. Does the transorb have to comply with a specific EN safety standard (like
one applicable to Y caps)?

Thanks,

Alexandru Guidea

CAE Inc.
Canada





Basic
 Insulation
|
|
ELV||---FUSE--SELV (??)
|  T
|  R
   A
   N
   S
   O
   R
   B
|
|
  GND (EARTH)





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reinforced insulation - EN60950

[Alexandru Guidea]

Strange behavior of the list-server. Although I got some out-of-office
replies, neither I or my fellows in the office (members of the list) have
received the message posted 24 h ago. I'll try again...



Dear colleagues,

As part of a PCB design required to be compliant with EN60950, we want to
use the configuration described below, to be able to relax the traces
separation. The circuit intended to become SELV is accessible to the
operator.

Questions:
1. Is the combination of Basic Insulation + Fuse&Transorb(15V) equivalent to
Reinforced Insulation?
2. Does the transorb have to comply with a specific EN safety standard (like
one applicable to Y caps)?

Thanks,

Alexandru Guidea

CAE Inc.
Canada





Basic
 Insulation
|
|
ELV||---FUSE--SELV (??)
|  T
|  R
   A
   N
   S
   O
   R
   B
|
|
  GND (EARTH)





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RE: EN60950-1 - Time Scale??

[Kevin Richardson]

Peter,
 
For Australia & New Zealand 
AS/NZS 60950-1 has completed the public comment period.  There a couple of
comments which need to be resolved but hopefully these will not hold it up too
much.
As such, with any luck it should be published within a few months.
 

Best regards, 
Kevin Richardson 

Stanimore Pty Limited 
Compliance Advice & Solutions for Technology 
(Legislation/Regulations/Standards/Australian Agent Services) 
Ph:   02-4329-4070   (Int'l: +61-2-4329-4070) 
Fax:  02-4328-5639   (Int'l: +61-2-4328-5639) 
Mobile:  04-1224-1620   (Int'l: +61-4-1224-1620) 
Email:kevin.richard...@ieee.org 

This material (this message and the information contained in all attachments
to this message) is confidential and/or privileged information and is intended
only for the addressee/s named above. Any unauthorised dissemination, copying,
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please notify Stanimore Pty Limited and destroy all copies (electronic and
hardcopy) of this message and all attachments immediately.


From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of peter merguerian
Sent: Friday, 7 February 2003 5:09 AM
To: emc-p...@majordomo.ieee.org
Subject: EN60950-1 - Time Scale??



Group,

EN60950-1 appears in the OJ and there is a CB TRF issued by Fimko to this
standard. 

Is it wise to obtain a CB Test Report and Certificate to this standard when
most countries, including the US and Canada, have not adopted their versions
of the standard?

What is going on around the world to adopt the IEC 60950-1 standard?

 

Peter




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Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[peter merguerian]

Dear Friends,

Thanks very much to the input regarding CB Tripping During Fault Testing.
There were many thoughts on the subject and I am sure that next time the wall
CB trips during fault tests at your third part certification laboratory, you
have something to talk about - make sure they do not charge you for the
discussion time!

Peter




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RE: EN60950-1 - Time Scale??

[Richard Hughes]

Peter, 

 

To answer your question directly, I would say that it is the choice of the
manufacture, based on their market (international or just European) and
product lifetime to make their decisions.

 

For instance, the OJEC in relation to the LVD states that the third amendment
to EN 60950 has a date of cessation of 1/7/2006: therefore, if a manufacturer
is today placing a product on the European market that has a product life that
extends beyond 1/7/2006 then they may well consider it useful to adopt EN
60950-1 now.  However, if the manufacturer's product only has a market life of
a couple of years and they want to make maximum use of the IECEE CB Scheme to
gain multiple approvals across the world then they may decide that one of the
earlier variants of IEC 60950 would be a better way to go.

 

In fact, I would like to ask a completely different but related question. 
Given that Europe ratified EN 60950-1 in December 2001, why has it taken so
long for other countries to adopt IEC 60950-1 as their own national standard? 
Particularly so for those countries whose native language is English or French
and so the task of translation should be minimal.

 

While on the subject of what's going on around the world to adopt IEC 60950-1,
perhaps you have some information regarding the situation in Israel?

 

Regards,

 

Richard Hughes


From: peter merguerian [mailto:pmerguerian2...@yahoo.com]
Sent: 06 February 2003 18:09
To: emc-p...@majordomo.ieee.org
Subject: EN60950-1 - Time Scale??



Group,

EN60950-1 appears in the OJ and there is a CB TRF issued by Fimko to this
standard. 

Is it wise to obtain a CB Test Report and Certificate to this standard when
most countries, including the US and Canada, have not adopted their versions
of the standard?

What is going on around the world to adopt the IEC 60950-1 standard?

Peter




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Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Rich Nute]

Hi Peter:


My comments were based on the proposed requirement to
test the PE path with the circuit prospective current
transient, e.g. 200 amps from a 10,000-amp source for 
the period of time required to operate the overcurrent 
device  -- say less than a second or so.

(The 200 amps is a function of the contact resistances 
and the wire resistances, independent of the fault; 
the duration is a function of the overcurrent device.
200 amps is a reasonable number for plug-and-socket
cord-connected products.)

In order to get this maximum current, the fault must
be near zero ohms for the duration of the current
transient.  

To achieve near-zero ohms, the fault must be a large-
area fault.  A small-area fault is likely to fuse
open due to the current density and resistance at the
contact.

(I had the unfortunate experience that such a test by
a cert house used a small-area contact at a point where
no basic insulation fault could occur; the PWB PE path
was destroyed.  We repeated the test at a large-area
contact where basic insulation could fault, and the
PWB PE path passed.)

>   What if the over current device operates, the earthing path
>   is compromised by the fault, but not destroyed?  

I believe this is the objective of the proposal -- to
test the PE path with the circuit prospective current.
I would expect the compliance criterion to be no damage 
to the PE path.

>   What if the fault is of nonnear-zero impedance, the earthing
>   path is damaged, but not opened, and resetting of the
>   breaker does occur, but at some point the breaker holds due
>   to the relatively high impedance?

This scenario moves from withstanding the circuit 
prospective current to withstanding the steady-state
current just below the operating point of the over-
current device.  

I suggest that this is the objective of the existing 
requirement to test at twice the overcurrent device
rating or 25 amps, whichever is less.

>   a relatively complex earthing path, I have prepared a
>   separate e-mail that includes some construction details and
>   empirical data for a product in my lab.  To be sent soon.

I appreciate you sharing this data.


Best regards,
Rich






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EN60950-1 - Time Scale??

[peter merguerian]

Group,

EN60950-1 appears in the OJ and there is a CB TRF issued by Fimko to this
standard. 

Is it wise to obtain a CB Test Report and Certificate to this standard when
most countries, including the US and Canada, have not adopted their versions
of the standard?

What is going on around the world to adopt the IEC 60950-1 standard?

 

Peter




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RE: EN60950 protective conductor test

[boconn...@t-yuden.com]

Sir 

Based on *anecdotal* experience, use of PWB trace for P.E. is common only in
SMPSs that have no chassis or surrounding frame. For example, my employer,
mostly for the reasons published in this thread, does not use a PWB-only P.E
on any (AC/DC converter) SMPS. While my employer offers some frame-less DC/DC
converters that do have a "de-facto" PW-based P.E., none are intended for the
TNV enviroment.

And, AFAIK, all Class 1 SMPS should have a chassis-based P.E. 

R/S, 
Brian 

-Original Message- 
From: John Woodgate 

I read in !emc-pstc that Rich Nute  wrote (in 
<200302051810.kaa05...@epgc264.sdd.hp.com>) about 'EN60950 protective 
conductor test' on Wed, 5 Feb 2003: 

>In my experience, PWB PE circuits are common, 
>and most difficult to obviate. 

So says our SMPS expert on the national committee. Well, chacun à son 
gout: I'll do my best to avoid them entirely. 
-- 
Regards, John Woodgate 

RE: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Peter L. Tarver]

This thread has been largely theoretical.  Let's look at
some empirical test results for a product I just completed
testing.

The product has a redundant power configuration and nearly
identical current paths for each of two power supplies,
though one has about 2 in. longer traces on one side of one
of the boards involved.  There is no supplementary
overcurrent protection between the appliance inlets and the
input connections of the power supplies.

The earthing path involves the following:

filtered appliance inlet -->
quick-disconnect on filter -->
~1.5 in. No. 18 AWG terminated in a ring lug -->
earthing stackup on a PEM stud of ring lug (from filter),
KEPS nut, ring lug for downstream earthing, KEPS nut -->
~15 in. No. 18 AWG to a header style, soldered through-hole
interconnect -->
traces -->
soldered through-hole interconnect (for hot swappable power
supply) -->
soldered through-hole interconnect -->
traces -->
soldered through-hole to a header style, interconnect -->
~9 in. No. 18 AWG -->
soldered through-hole to a header style, interconnect on the
power supply -->
internal power supply magic -->
large, open-frame heatsink on power supply

This testing was first performed in situ and as intended in
normal use.  I believe this test configuration should be
used for the purposes of safety certification.

In each of the following cases, the earthing impedance test
current was maintained for 2 minutes.  These tests were
performed "precompliance."

I first tested the shortest path.

before faulting test current: 20.0 A
after faulting test current: 20.4 A

before faulting: 0.008 Ohm (a 0.016 V drop across the path)
after faulting: 0.006 Ohm (a 0.012 V drop across the path)

Surprising to have a lower impedance final result.  So much
so, I assumed I must have done something incorrectly,
reflowed a bad solder joint, initiated metal migration ...
something, either during the fault test, the earthing
impedance test or both.

Based on the product's construction, I knew that some
incidental current paths contributed to the very low
earthing impedance.  I then removed the assemblies of
interest from the main chassis and retested on the other of
the two circuits, so that only the current path of specific
interest was involved.  I left the main protective earthing
connection intact on the chassis.  Testing the longest path,

before faulting test current: 20.5 A
after faulting test current: 20.4 A

before faulting: 0.038 Ohm (a 0.77 V drop across the path)
after faulting: 0.037 Ohm (a 0.75 V drop across the path)

Still compliant at a ~20 A current value and still an
apparent *reduction* in the impedance of the earthing path.
This is not coincidence and double checking my test methods
along the way told me there were no errors.

I performed a third test on the same sample, longest path,
still outside the enclosure.

before faulting test current: 20.4 A
after faulting test current: 30.2 A

before faulting: 0.036 Ohm (a 0.74 V drop across the path)
after faulting: 0.041 Ohm (a 1.24 V drop across the path)


The above testing was repeated in situ on a new test sample.
The earthing impedance test, before and after, was set to 40
A.  The results were very similar to those for the first in
situ test, with almost identical calculated impedances, and
the earthing path withstood the 40 A current very nicely.

It should be noted that I performed the fault on a 120V, 20
A branch circuit.  The product will be rated for 240 V and
CSA 22.2 No. 0.4 requires the test be performed on a circuit
with the voltage at the highest rating marked on the
product, but I only have 20 A circuits on 120V circuits; my
208 V circuits, which I can boost to 240V, are all 30 A.


Regards,

Peter L. Tarver, PE
Product Safety Manager
Sanmina-SCI Homologation Services
San Jose, CA
peter.tar...@sanmina-sci.com





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RE: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Peter L. Tarver]

> From: Rich Nute
> Sent: Wednesday, February 05, 2003 12:20 PM
>
> Hi Peter:

Hi, Rich.

> This test implies a near 0-ohm fault to the
> PE, where the PE circuit includes a PE trace
> on the PWB.

That's a reasonable assumption and is convenient for the
purposes of testing.  It is unlikely to be the only fault
case, but that's irrelevant to compliance with the standard
and should be considered internally, to the level of pain
tolerable by any particular company.

> If there is a zero-ohm fault, an over-current
> device, somewhere, will operate.  (Indeed, this
> is the function of the PE circuit!)  A zero-ohm
> fault implies a large-area contact with a fair
> amount of contact pressure for at least the
> period of time to operate the overcurrent device.
>
> Consequently, the product must be removed from
> service and repaired before being returned to
> service.

What if the over current device operates, the earthing path
is compromised by the fault, but not destroyed?  Let us not
forget that there are many who will reset a circuit breaker
ad infinitum, to failure, reimposing a fault repeatedly.  (I
spoke this afternoon to a coworker who is also landlord.
One tenant consistently overloaded a branch circuit and
reset the circuit breaker repeatedly, until it failed to
close.)

Each resetting of the circuit imposes a similar fault, with
a progressively weaker earthing circuit.  Let us assume that
at some point short of circuit breaker failure, the earthing
path becomes compromised enough that the branch circuit does
not open the circuit.

What if the fault is of nonnear-zero impedance, the earthing
path is damaged, but not opened, and resetting of the
breaker does occur, but at some point the breaker holds due
to the relatively high impedance?

We can let our imaginations wander from there and each
believe as we will that thus and such will or will not,
could or could not happen and debate the probabilities until
the ruminants return hither.  Bad stuff happens: dead-front
switchboards explode, fires are started by minor appliances
with safety certification house marks or questionable wiring
practices, trains jump the tracks...


> If the 0-ohm fault is on the PWB, then the PWB
> will need to be replaced.  It is difficult to
> imagine a fault of 0-ohm proportions that could
> be repaired without replacing the PWB assembly.
> Indeed, if the PWB PE circuit carries the high
> transient current, it may very well be that the
> supply conductors on the PWB may be blown off
> the PWB.  So, I question whether the compliance
> criteria need be applied.

If.  The fault might occur anywhere in the earthing path.
To give an idea of how a relatively simple idea can lead to
a relatively complex earthing path, I have prepared a
separate e-mail that includes some construction details and
empirical data for a product in my lab.  To be sent soon.


> >   There is also the much more variable solder
> in the earthing
> >   path.  While manufacturing techniques have
> come a long way
> >   in terms of consistency, the amount of solder
> in a joint and
> >   the quality of the joint itself can play a
> significant role.
> >   It should be expected that a lower melting
> point solder will
> >   perform less well than a higher melting point solder.
> >   Appropriate process controls will have a
> positive effect.
>
> An ideal solder joint involves an amalgam at
> the joint with the conductors.  The properties
> of the amalgam are typically "greater" than
> the property of either material alone.  As in
> copper plumbing joints, an idea joint has very
> little solder between the two components being
> joined.

And yet, mass production of electrical and electronic
products, while generally yielding consistent-quality
products when produced in a conscientious environment, can
still have variability and initially undetectable problems
that even HALT testing can't predict and HASS testing can't
weed out.  There will be very few companies with zero field
returns where cracks develop in a laminate, solder joints
fail or are imperfect to the point of eventually some flaw
eventually rears its head.

The goal is to at least offer the impression that a
construction will not yield an insidious hazard at some
point in the future.  My recent experience has led me to
believe that, aside from a few head scratching results, the
test is *very* simple to perform and requires almost *no*
additional test equipment, over and above an earthing
impedance test setup and a modicum of ingenuity inherent in
any engineer.

> My guess would be that the current path will be
> that of least resistance, which will minimize
> the current through the solder around the joint.
> So, I would doubt that the solder (of a good
> joint) would be much affected by the current
> pulse.
>
>
> Best regards,
> Rich

There's no question that incidental currents can have a
positive effect, even if not considered "reliable."  There's
no denying that it is possible to comply with the 

Re: EN60950 protective conductor test

[John Woodgate]

I read in !emc-pstc that Rich Nute  wrote (in
<200302051810.kaa05...@epgc264.sdd.hp.com>) about 'EN60950 protective
conductor test' on Wed, 5 Feb 2003:

>In my experience, PWB PE circuits are common, 
>and most difficult to obviate.

So says our SMPS expert on the national committee. Well, chacun à son
gout: I'll do my best to avoid them entirely. 
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Rich Nute]

Hi Peter:


>   Not quite.  I^2·t will tell you the let through current of
>   the copper trace, but will not necessarily tell you if the
>   construction will be compliant.  The compliance criteria for
>   this test include:
>   
>   * no damage to the trace (no lifting, probably no
>   discoloration)
>   * no damage to the PWB (no delamination, burning; I don't
>   know if this includes burning off of solder mask)
>   * before and after earthing impedance must comply with the
>   0.1 Ohm maximum impedance
>   * no change in earthing impedance greater than 10% of the
>   before and after earthing impedance results

This test implies a near 0-ohm fault to the
PE, where the PE circuit includes a PE trace 
on the PWB.

If there is a zero-ohm fault, an over-current
device, somewhere, will operate.  (Indeed, this
is the function of the PE circuit!)  A zero-ohm
fault implies a large-area contact with a fair
amount of contact pressure for at least the 
period of time to operate the overcurrent device.

(A point-contact fault would blow a hole in the
copper trace due to very high current density
at the point of contact.)

Consequently, the product must be removed from
service and repaired before being returned to
service.

If the 0-ohm fault is on the PWB, then the PWB
will need to be replaced.  It is difficult to
imagine a fault of 0-ohm proportions that could
be repaired without replacing the PWB assembly.
Indeed, if the PWB PE circuit carries the high
transient current, it may very well be that the
supply conductors on the PWB may be blown off
the PWB.  So, I question whether the compliance 
criteria need be applied.

>   There is also the much more variable solder in the earthing
>   path.  While manufacturing techniques have come a long way
>   in terms of consistency, the amount of solder in a joint and
>   the quality of the joint itself can play a significant role.
>   It should be expected that a lower melting point solder will
>   perform less well than a higher melting point solder.
>   Appropriate process controls will have a positive effect.

An ideal solder joint involves an amalgam at 
the joint with the conductors.  The properties
of the amalgam are typically "greater" than 
the property of either material alone.  As in
copper plumbing joints, an idea joint has very
little solder between the two components being
joined.

My guess would be that the current path will be
that of least resistance, which will minimize
the current through the solder around the joint.
So, I would doubt that the solder (of a good
joint) would be much affected by the current
pulse.


Best regards,
Rich





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Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Rich Nute]

Hi Chris:


>   It seems funny to me that most equipment has been historically made with
18AWG protective ground pigtail wires; and 25A ground fault tests have been
used for years.  
>   
>   Now that PC  traces are being used for protective ground; we want to test
with 200A or greater impulse currents?  I'm curious about what would happen to
your typical 18AWG line cord during this test.  I'm wondering if the line cord
would fuse open? 

The 18 AWG readily passes the circuit prospective
current test.  This is because the current is
transient, and is cut off before the wire in the 
cord can reach fusing temperature.

>   One is at www.kepcopower.com/nomovax2.htm this is a nomograph of maximum
operating current, AWG and IR drop in the conductor.  The point "A" is
generally considered the point of maximum IR drop.  If you draw a line from
point "A", through a wire gauge size; you'll get a max current.  Of course
this is steady state current; and the nomograph assumes a single wire.  Wire
bundles would be a worse case.  It's too bad that this chart doesn't contain
the "fuse" values for the wires as well (the  I squared * T values).

Fusing currents for wires are published in:

Reference Data for Radio Engineers
International Telephone and Telegraph Corporation
67 Broad Street
New York 4, New York

This reference says "Courtesy of Automatic 
Electric Company, Chicago, Illinois."

The approximate fusing current for 18 AWG copper 
is 82.9 amperes.

The approximate fusing current of wires can be 
calculated from:

I  =  (K) * (d**3/2)

where d is the diameter of the wire, in inches
  K is a constant that depends on the metal

Here are some values for K:

copper:10,244
aluminum:   7,585
silver: 5,230
iron:   3,148
tin:1,642

The "Standard Handbook for Electrical Engineers"
by Fink and Beatty has some additional data,
including curves of current and time for each
AWG.  A couple of points for 18 AWG:

   0.1 second:~720 amps
   1.0 second:~220 amps
  10.0 second:~ 82 amps
   
>   3.  The third problem is mechanical.  Once Earth ground brought to a pad
on the circuitboard; then there is still the issue of getting a good
mechanical mate to the chassis with a wide surface area.  If the connection is
made through a couple of teeth on a star washer; then there is a potential for
localized heating.   I'm just going to maximize surface contact area for this
one.  I'm also considering using multiple board to chassis connection
locations.  Every screw that connects the board to chassis is a potential
Earth ground connection.

The problem with mechanical connections to PWBs 
by means of screws is that the PWB base material 
is a plastic and is subject to cold-flow under 
compressive conditions.  In the long-term, the
connection can loosen.  

Not everyone pays attention to this, and, in 
practice, it is rarely a problem.

One way around this is to use a wire from the 
board to the chassis.


Best regards,
Rich






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Re: EN60950 protective conductor test

[Rich Nute]

Hi John:


>   Is it not permitted to express a personal preference on this group? I
>   *prefer, personally*, not to use printed board traces as parts of the
>   PEC. I'm not suggesting that should be in IEC 60950 or any other
>   standard.

Of course we express personal preferences in
this group!  Almost every message is a personal
preference.  :-)

The point of my message is to argue against your
personal preference as there is nothing inherently
wrong with PWB traces as part of the PE circuit.

Some SMPS use a grounded heat sink -- on the PWB 
-- for the switching transistors.  In this case, 
the electrical circuit path from the heat sink to
the earth terminal of the IEC 60320 connector is
a part of the PE circuit, and must be capable of
carrying the fault current.  Running a wire from 
the heat sink to the terminal is a manual job, 
and introduces two connections that are operator-
dependent whereas the PWB connections are not.

Another point... which I hesitate to mention...
is that, while Y2 capacitors require connection 
to a PE return, some test houses require a PE 
return for Y1 capacitors!

In my experience, PWB PE circuits are common, 
and most difficult to obviate.


Best regards,
Rich






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RE: EN60950 protective conductor test (was Re: Circuit Breaker Tr ipping Dring Fault Tests)

[drcuthbert]

I recently designed a piece of in-house gear that uses the PCB as part of
the protective earth GND return. At first I thought I would be forced to use
a wire(s) only (which was awkward given the mechanics of the unit) but then
was convinced that EN61010 did not require it. To get around the via issue
we kept the path on one PCB layer. We designed for well over 20 amps
continuous. The bare metal rear panel is connected to the power connector
GND with the standard YELLOW/GREEN wire. The cabinet and front panel are
connected through the PCB with either metal spacers or a metal bracket. When
testing this do I return the current through the rear panel only, or do two
more tests using the cabinet and the front panel? The cabinet and the front
panel do not have dedicated GND connections or any unpainted metal.

   Dave Cuthbert
   Micron Technology



From: Chris Maxwell [mailto:chris.maxw...@nettest.com]
Sent: Tuesday, February 04, 2003 11:25 AM
To: Lou Aiken; Peter L. Tarver; emc-p...@majordomo.ieee.org
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)



PC traces are easier to assemble and the assembly can be done in a tighter
space.  I think (just an opinion)  that proper design could make this type
of system more reliable as well with less chances of wires coming loose...

> -Original Message-
> From: Lou Aiken [SMTP:ai...@gulftel.com]
> Sent: Tuesday, February 04, 2003 11:36 AM
> To:   Peter L. Tarver; emc-p...@majordomo.ieee.org
> Subject:  Re: EN60950 protective conductor test (was Re: Circuit
Breaker Tripping Dring Fault Tests)
> 
> 
> Why not provide a fuse to prevent deterioration of the PE trace on a PCB?
> 
> Joking of course, but now that I have your attention, I would like to see
> this thread move away from the physics and discuss what practical reasons
> there are for using PC traces to provide earth fault circuits.
> 
> 
> Lou Aiken, LaMer LLC
> 27109 Palmetto Drive
> Orange Beach, AL
> 36561 USA
> 
> tel ++ 1 251 981 6786
> fax ++ 1 251 981 3054
> Cell ++ 1 251 979 4648
> - Original Message -
> From: Peter L. Tarver 
> To: 
> Sent: Tuesday, February 04, 2003 9:53 AM
> Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
> Tripping Dring Fault Tests)
> 
> 
> 
> Not quite.  I^2·t will tell you the let through current of
> the copper trace, but will not necessarily tell you if the
> construction will be compliant.  The compliance criteria for
> this test include:
> 
> * no damage to the trace (no lifting, probably no
> discoloration)
> * no damage to the PWB (no delamination, burning; I don't
> know if this includes burning off of solder mask)
> * before and after earthing impedance must comply with the
> 0.1 Ohm maximum impedance
> * no change in earthing impedance greater than 10% of the
> before and after earthing impedance results
> 
> There is also the much more variable solder in the earthing
> path.  While manufacturing techniques have come a long way
> in terms of consistency, the amount of solder in a joint and
> the quality of the joint itself can play a significant role.
> It should be expected that a lower melting point solder will
> perform less well than a higher melting point solder.
> Appropriate process controls will have a positive effect.
> 
> These are some of the reasons some form of safety agency
> factory auditing of this type of construction is normal.
> 
> 
> Regards,
> 
> Peter L. Tarver, PE
> Product Safety Manager
> Sanmina-SCI Homologation Services
> San Jose, CA
> peter.tar...@sanmina-sci.com
> 
> 
> > -Original Message-
> > From: Chris Maxwell
> > Sent: Tuesday, February 04, 2003 5:32 AM
> >
> >
> > Exactly!
> >
> > Chris Maxwell
> >
> >
> > > -Original Message-
> > > From: drcuthbert [SMTP:drcuthb...@micron.com]
> > > Sent: Monday, February 03, 2003 7:50 PM
> > >
> > > What is needed is the I squared t rating of the
> > breaker. Then the (I^2)(t)
> > > rating of the PCB. Then you know if the PCB can
> > take it.
> > >
> > >Dave Cuthbert
> 
> 
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
> 
> Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
> 
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EN60950 protective conductor test (was Re: Circuit Breaker Tr ipping Dring Fault Tests)

[John Woodgate]

I read in !emc-pstc that drcuthbert  wrote (in
)
about 'EN60950 protective conductor test (was Re: Circuit Breaker Tr
ipping Dring Fault Tests)' on Tue, 4 Feb 2003:

>The results would then
>be published in Compliance, Conformity, or Printed Circuit design magazine.

Please also send them to your experts on your TC108 national committee.
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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RE: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Gary McInturff]

Lou,
I'm not proposing anything mind you, but you could save some space if 
you had
a PWB mounted appliance inlet and you would still have to get the PEC to the
chassis. 
Gary


From: Lou Aiken [mailto:ai...@gulftel.com]
Sent: Tuesday, February 04, 2003 8:36 AM
To: Peter L. Tarver; emc-p...@majordomo.ieee.org
Subject: Re: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)



Why not provide a fuse to prevent deterioration of the PE trace on a PCB?

Joking of course, but now that I have your attention, I would like to see
this thread move away from the physics and discuss what practical reasons
there are for using PC traces to provide earth fault circuits.


Lou Aiken, LaMer LLC
27109 Palmetto Drive
Orange Beach, AL
36561 USA

tel ++ 1 251 981 6786
fax ++ 1 251 981 3054
Cell ++ 1 251 979 4648

From: Peter L. Tarver 
To: 
Sent: Tuesday, February 04, 2003 9:53 AM
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)



Not quite.  I^2·t will tell you the let through current of
the copper trace, but will not necessarily tell you if the
construction will be compliant.  The compliance criteria for
this test include:

* no damage to the trace (no lifting, probably no
discoloration)
* no damage to the PWB (no delamination, burning; I don't
know if this includes burning off of solder mask)
* before and after earthing impedance must comply with the
0.1 Ohm maximum impedance
* no change in earthing impedance greater than 10% of the
before and after earthing impedance results

There is also the much more variable solder in the earthing
path.  While manufacturing techniques have come a long way
in terms of consistency, the amount of solder in a joint and
the quality of the joint itself can play a significant role.
It should be expected that a lower melting point solder will
perform less well than a higher melting point solder.
Appropriate process controls will have a positive effect.

These are some of the reasons some form of safety agency
factory auditing of this type of construction is normal.


Regards,

Peter L. Tarver, PE
Product Safety Manager
Sanmina-SCI Homologation Services
San Jose, CA
peter.tar...@sanmina-sci.com


> -Original Message-
> From: Chris Maxwell
> Sent: Tuesday, February 04, 2003 5:32 AM
>
>
> Exactly!
>
> Chris Maxwell
>
>
> > -Original Message-
> > From: drcuthbert [SMTP:drcuthb...@micron.com]
> > Sent: Monday, February 03, 2003 7:50 PM
> >
> > What is needed is the I squared t rating of the
> breaker. Then the (I^2)(t)
> > rating of the PCB. Then you know if the PCB can
> take it.
> >
> >Dave Cuthbert



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RE: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Chris Maxwell]

PC traces are easier to assemble and the assembly can be done in a tighter
space.  I think (just an opinion)  that proper design could make this type of
system more reliable as well with less chances of wires coming loose...

> -Original Message-
> From: Lou Aiken [SMTP:ai...@gulftel.com]
> Sent: Tuesday, February 04, 2003 11:36 AM
> To:   Peter L. Tarver; emc-p...@majordomo.ieee.org
> Subject:  Re: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)
> 
> 
> Why not provide a fuse to prevent deterioration of the PE trace on a PCB?
> 
> Joking of course, but now that I have your attention, I would like to see
> this thread move away from the physics and discuss what practical reasons
> there are for using PC traces to provide earth fault circuits.
> 
> 
> Lou Aiken, LaMer LLC
> 27109 Palmetto Drive
> Orange Beach, AL
> 36561 USA
> 
> tel ++ 1 251 981 6786
> fax ++ 1 251 981 3054
> Cell ++ 1 251 979 4648
> - Original Message -
> From: Peter L. Tarver 
> To: 
> Sent: Tuesday, February 04, 2003 9:53 AM
> Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
> Tripping Dring Fault Tests)
> 
> 
> 
> Not quite.  I^2·t will tell you the let through current of
> the copper trace, but will not necessarily tell you if the
> construction will be compliant.  The compliance criteria for
> this test include:
> 
> * no damage to the trace (no lifting, probably no
> discoloration)
> * no damage to the PWB (no delamination, burning; I don't
> know if this includes burning off of solder mask)
> * before and after earthing impedance must comply with the
> 0.1 Ohm maximum impedance
> * no change in earthing impedance greater than 10% of the
> before and after earthing impedance results
> 
> There is also the much more variable solder in the earthing
> path.  While manufacturing techniques have come a long way
> in terms of consistency, the amount of solder in a joint and
> the quality of the joint itself can play a significant role.
> It should be expected that a lower melting point solder will
> perform less well than a higher melting point solder.
> Appropriate process controls will have a positive effect.
> 
> These are some of the reasons some form of safety agency
> factory auditing of this type of construction is normal.
> 
> 
> Regards,
> 
> Peter L. Tarver, PE
> Product Safety Manager
> Sanmina-SCI Homologation Services
> San Jose, CA
> peter.tar...@sanmina-sci.com
> 
> 
> > -Original Message-
> > From: Chris Maxwell
> > Sent: Tuesday, February 04, 2003 5:32 AM
> >
> >
> > Exactly!
> >
> > Chris Maxwell
> >
> >
> > > -Original Message-
> > > From: drcuthbert [SMTP:drcuthb...@micron.com]
> > > Sent: Monday, February 03, 2003 7:50 PM
> > >
> > > What is needed is the I squared t rating of the
> > breaker. Then the (I^2)(t)
> > > rating of the PCB. Then you know if the PCB can
> > take it.
> > >
> > >Dave Cuthbert
> 
> 
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
> 
> Visit our web site at:  http://www.ewh.ieee.org/soc/emcs/pstc/
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> 
> 
> 
> 
> ---
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Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[John Barnes]

Chris,
Douglas Brooks wrote an article about Preese's and Onderdonk's equations
for fusing currents of wires, which was published in Printed Circuit
Magazine.  It can be downloaded from UltraCAD's web site at
http://www.ultracad.com/fusing.pdf

Appendix F of the book that I am writing for Kluwer, Robust Electronic
Design Reference, will cover the ampacity (current-carrying capacity) of
wires, printed circuit board traces, busbars, etc.  The manuscript is
due August 1st, so I had better get back to my writing...

John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE
dBi Corporation
http://www.dbicorporation.com/


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Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fa

[Cortland Richmond]

Lou Aiken wrote 

>> ... what practical reasons there are for using PC traces to provide
earth fault circuits. <<

One practical reason is, to cut costs and simplify construction. Some years
ago a former employer designed and made a computer power supply with the
safety ground on the board, and UL allowed it. It was necessary to make the
board rugged enough at the grounding point to accept a standard, threaded
stud, nut and washer combination; they would not budge on THAT. It survived
fault current tests just fine. 

What we got from this was the ability to put everything, including an IEC
power connector, on one board, and eliminate flying wires.

I've also seen current requirements which could not be reasonably met using
a PWB trace, and in that case, a heavy bus strap was soldered onto the
board. This is a viable replacement where space or fabrication constraints
don't allow for the heavy, wide traces high current incurs. This
construction may be a reasonable answer to  some of the issues here.

Cortland


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Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[John Woodgate]

I read in !emc-pstc that Chris Maxwell  wrote
(in <83d652574e7af740873674f9fc12dbaaf7e...@utexh1w2.gnnettest.com>)
about 'EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)' on Tue, 4 Feb 2003:

>This would make heat dissipation different; and I would assume that it would 
>make the fusing characteristics (I^2)(t) slightly different as well.

Or even a lot different. The reason why I personally would not use a
printed board trace as a PEC is that boards can develop cracks and thin
copper patches, so I couldn't guarantee that every board would stand the
test that the test sample passed. In this case, I don't think
potentially destructive sample testing is adequate, either. The PEC
needs to be 'four nines' reliable.
-- 
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk 
Interested in professional sound reinforcement and distribution? Then go to 
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!


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Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Lou Aiken]

Why not provide a fuse to prevent deterioration of the PE trace on a PCB?

Joking of course, but now that I have your attention, I would like to see
this thread move away from the physics and discuss what practical reasons
there are for using PC traces to provide earth fault circuits.


Lou Aiken, LaMer LLC
27109 Palmetto Drive
Orange Beach, AL
36561 USA

tel ++ 1 251 981 6786
fax ++ 1 251 981 3054
Cell ++ 1 251 979 4648

From: Peter L. Tarver 
To: 
Sent: Tuesday, February 04, 2003 9:53 AM
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)



Not quite.  I^2·t will tell you the let through current of
the copper trace, but will not necessarily tell you if the
construction will be compliant.  The compliance criteria for
this test include:

* no damage to the trace (no lifting, probably no
discoloration)
* no damage to the PWB (no delamination, burning; I don't
know if this includes burning off of solder mask)
* before and after earthing impedance must comply with the
0.1 Ohm maximum impedance
* no change in earthing impedance greater than 10% of the
before and after earthing impedance results

There is also the much more variable solder in the earthing
path.  While manufacturing techniques have come a long way
in terms of consistency, the amount of solder in a joint and
the quality of the joint itself can play a significant role.
It should be expected that a lower melting point solder will
perform less well than a higher melting point solder.
Appropriate process controls will have a positive effect.

These are some of the reasons some form of safety agency
factory auditing of this type of construction is normal.


Regards,

Peter L. Tarver, PE
Product Safety Manager
Sanmina-SCI Homologation Services
San Jose, CA
peter.tar...@sanmina-sci.com


> -Original Message-
> From: Chris Maxwell
> Sent: Tuesday, February 04, 2003 5:32 AM
>
>
> Exactly!
>
> Chris Maxwell
>
>
> > -Original Message-
> > From: drcuthbert [SMTP:drcuthb...@micron.com]
> > Sent: Monday, February 03, 2003 7:50 PM
> >
> > What is needed is the I squared t rating of the
> breaker. Then the (I^2)(t)
> > rating of the PCB. Then you know if the PCB can
> take it.
> >
> >Dave Cuthbert



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RE: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)

[Peter L. Tarver]

Not quite.  I^2·t will tell you the let through current of
the copper trace, but will not necessarily tell you if the
construction will be compliant.  The compliance criteria for
this test include:

* no damage to the trace (no lifting, probably no
discoloration)
* no damage to the PWB (no delamination, burning; I don't
know if this includes burning off of solder mask)
* before and after earthing impedance must comply with the
0.1 Ohm maximum impedance
* no change in earthing impedance greater than 10% of the
before and after earthing impedance results

There is also the much more variable solder in the earthing
path.  While manufacturing techniques have come a long way
in terms of consistency, the amount of solder in a joint and
the quality of the joint itself can play a significant role.
It should be expected that a lower melting point solder will
perform less well than a higher melting point solder.
Appropriate process controls will have a positive effect.

These are some of the reasons some form of safety agency
factory auditing of this type of construction is normal.


Regards,

Peter L. Tarver, PE
Product Safety Manager
Sanmina-SCI Homologation Services
San Jose, CA
peter.tar...@sanmina-sci.com


> -Original Message-
> From: Chris Maxwell
> Sent: Tuesday, February 04, 2003 5:32 AM
>
>
> Exactly!
>
> Chris Maxwell
>
>
> > -Original Message-
> > From:   drcuthbert [SMTP:drcuthb...@micron.com]
> > Sent:   Monday, February 03, 2003 7:50 PM
> >
> > What is needed is the I squared t rating of the
> breaker. Then the (I^2)(t)
> > rating of the PCB. Then you know if the PCB can
> take it.
> >
> >Dave Cuthbert



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RE: EN60950 protective conductor test (was Re: Circuit Breaker Tr ipping Dring Fault Tests)

[drcuthbert]

Chris,
I have estimated this type of thing in the past assuming adiabatic
conditions. That is, the energy put into the material heats it and no energy
is lost during the heating. This gives the worse-case temperature rise. So,
what is needed is the electrical resistance of the material and the specific
heat of the material. Let's look at the case of a trace sized to handle 25
amps continuously with a 40 degree C rise.
http://www.geocities.com/CapeCanaveral/Lab/9643/TraceWidth.htm

We will pulse it with 200 amps for 20 ms and see what the heat rise is
assuming adiabatic conditions:

The trace is 500 mils (1.27 cm) wide, 1 inch (2.54 cm) long, and is 1 oz
copper (1.4 mils or 3.55 x10^-3 cm). The resistance is 1 milliohm. The
energy absorbed is (I^2)(R)(t) = 0.8 joules. The density of copper is 8.96
gr/cm^3. The mass of this trace is 0.103 gr. The specific heat of copper is
0.386 J/gr*C. The specific heat of this trace is therefore 0.0398J/C which
gives a heat rise of 20 degrees C for a 200 amp, 20ms pulse.  I have
neglected the change in resistance and specific heat with temp.

I have actually viewed the voltage drop across a metal line as it was heated
by a pulse. From this one can plot the temperature versus time. The real
issue, I think are the vias and vias with heat reliefs. How many do we use?
We can calculate the vias the same way and come up with a recommendation. Of
course, it would be great to check this with experiments. I would be
interested in doing this if someone here wants to partner on the project. I
can have a test board designed and built and do the pulsing. What I need are
standards, suggestions, circuit breaker data, and any other help (such as
researching to see if we are reinventing the wheel. The results would then
be published in Compliance, Conformity, or Printed Circuit design magazine.


 Dave Cuthbert
 Micron Technology


From: Chris Maxwell [mailto:chris.maxw...@nettest.com]
Sent: Tuesday, February 04, 2003 6:32 AM
To: drcuthbert; John Woodgate; emc-p...@majordomo.ieee.org
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)


Exactly!  There is lots of data and tables available on the web for steady
state current; but I haven't found any sources that would give the (I^2)(t)
values for wires or PCB traces.   Such tables would take a great deal of
mystery out of this subject.  Right now, the best guess is to go by steady
state current rating; but there must be faults in this.  A PCB trace that
can handle 10 Amps of steady state current has a totally different geometry
than a wire that can handle 10 Amps of steady state current.  This would
make heat dissipation different; and I would assume that it would make the
fusing characteristics (I^2)(t) slightly different as well.

Chris Maxwell | Design Engineer - Optical Division
email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024

NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA
web www.nettest.com | tel +1 315 797 4449 | 




> -Original Message-
> From: drcuthbert [SMTP:drcuthb...@micron.com]
> Sent: Monday, February 03, 2003 7:50 PM
> To:   'John Woodgate'; emc-p...@majordomo.ieee.org
> Subject:  RE: EN60950 protective conductor test (was Re: Circuit
Breaker Tripping Dring Fault Tests)
> 
> 
> What is needed is the I squared t rating of the breaker. Then the (I^2)(t)
> rating of the PCB. Then you know if the PCB can take it. 
> 
>Dave Cuthbert
> 
> 


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