John (& Charlie), Yes, I believe I also said that, under Euro CE marking & now
British UKCA, self-certification is allowed but he mentioned that he was
concerned that a test house was pressing the issue. So, if he wants to get the
test house marking he either has to talk them out of it or comply with the
identified requirements.
But, let’s look at the technical requirements a bit. The use of
Voltage limits has been common for decades to declare circuits that are deemed
touch safe. This had been done under the assumption that any long time contact
with the circuit is small area of contact and dry conditions. For some
applications this may not be a good assumption downstream and, since the
allowed current (a few A in his case) is well above the 5mA
letgo-immobilization and the 30mA VF limit, then this condition must not be
abrogated for the circuit to remain safe to touch. You don’t even have to go
to single fault for this analysis. His risk analysis would include this line
of examination from which he would determine if this risk is acceptable and,
thus, deem the application acceptable.
:>) br, Pete
Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 1067
Albany, ORe 97321-0413
503/452-1201
IEEE Life Fellow
IEEE PSES 2020 Distinguished Lecturer
<http://www.researchgate.net/Peter%20Perkins> www.researchgate.net search my
name
<mailto:[email protected]> [email protected]
Entropy ain’t what it used to be
From: John Woodgate <[email protected]>
Sent: Wednesday, October 20, 2021 12:11 PM
To: [email protected]
Subject: Re: [PSES] IEC 62368-3:2017 evaluation of USB 2.0 ports
Hi, Pete. Isn't Charlie's option to say, with test results, that if he plugs
his product into a USBzilla source, it still remains safe under any
single-fault condition?
======================================================================================
Best wishes John Woodgate OOO-Own Opinions Only
www.woodjohn.uk <http://www.woodjohn.uk>
Rayleigh, Essex UK
Istae nunc praetereunt nisi non ubicumque
On 2021-10-20 19:52, Pete Perkins wrote:
Charlie, Remember that 62368-3 was developed at the direction of
ACOS to move the powered communication interfaces info from the 62368-1 base
standard to a separate document that would be available for use outside of
62368-1. The goal is to move this from the Wild West into an orderly set of
requirements that any product standard can use.
You claim that for the ‘simple circuit’ you mentioned the
limited power is safe as you see it. How does the user know if that simple
solution is implemented in any particular product and that it is safe?
The 62368-3 standard itself seems limiting so the requirements
are being rewritten into 2 new documents which will be more tailored to the two
realms under which these circuits work, <60Vdc and >60Vdc. TC108 has this work
underway.
Whether or not any of this is required is a matter for product
committees to specify and test labs to check.
Whether you want to use the requirements or not come down to
your understanding of the risk associated with the use (and misuse) of products
providing power over these communication interfaces and/or having them
specified in a mother standard.
:>) br, Pete
Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 1067
Albany, ORe 97321-0413
503/452-1201
IEEE Life Fellow
IEEE PSES 2020 Distinguished Lecturer
www.researchgate.net <http://www.researchgate.net/Peter%20Perkins> search my
name
[email protected] <mailto:[email protected]>
Entropy ain’t what it used to be
From: Charlie Blackham <mailto:[email protected]>
<[email protected]>
Sent: Wednesday, October 20, 2021 10:12 AM
To: [email protected] <mailto:[email protected]>
Subject: [PSES] IEC 62368-3:2017 evaluation of USB 2.0 ports
All
I realise there are now applications where 100W or more can be transferred, but
for devices with only USB2.0 ports, that are coming from the same chip, is
there really any need for testing and CB certification to this standard as part
of an assessment to IEC 62368-1?
The particular products I’m looking at are powered from external 5V LPS power
supplies that shutdown at around 4.5 A
I may just be being cynical, but I can’t see how the -3 standard makes such a
product any safer, it just seems to make the test lab richer 😊
Is there something in the CB scheme rules that mandates using the -3 standard
as well when seeking CB certificate?
Best regards
Charlie
Charlie Blackham
Sulis Consultants Ltd
Mead House
Longwater Road
Eversley
RG27 0NW
UK
Tel: +44 (0)7946 624317
Email: <mailto:[email protected]> [email protected]
Web: <https://sulisconsultants.com/> https://sulisconsultants.com/
Registered in England and Wales, number 05466247
-
----------------------------------------------------------------
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
<[email protected] <mailto:[email protected]> >
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 <[email protected] <mailto:[email protected]> >
Mike Cantwell <[email protected] <mailto:[email protected]> >
For policy questions, send mail to:
Jim Bacher <[email protected] <mailto:[email protected]> >
David Heald <[email protected] <mailto:[email protected]> >
-
----------------------------------------------------------------
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
<[email protected] <mailto:[email protected]> >
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 <[email protected] <mailto:[email protected]> >
Mike Cantwell <[email protected] <mailto:[email protected]> >
For policy questions, send mail to:
Jim Bacher <[email protected] <mailto:[email protected]> >
David Heald <[email protected] <mailto:[email protected]> >
<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
Virus-free.
<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
www.avg.com
-
----------------------------------------------------------------
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail to
<[email protected] <mailto:[email protected]> >
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 <[email protected] <mailto:[email protected]> >
Mike Cantwell <[email protected] <mailto:[email protected]> >
For policy questions, send mail to:
Jim Bacher <[email protected] <mailto:[email protected]> >
David Heald <[email protected] <mailto:[email protected]> >
-
----------------------------------------------------------------
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
<[email protected]>
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 <[email protected]>
Mike Cantwell <[email protected]>
For policy questions, send mail to:
Jim Bacher: <[email protected]>
David Heald: <[email protected]>
