Re: [PSES] IEC 61000-4-5 Surge Testing Single plug vs. multiple plug system

[John Woodgate]

I feel sure that

/"When testing line to ground, the lines are tested singly in sequence, 
if there is no other/

/specification."/

is about 3-phase supplies, not multiple mains leads.

Best wishes
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates www.woodjohn.uk
Rayleigh, Essex UK

On 2019-01-03 01:15, John Howe wrote:
IEC 61000-4-5 (2005) does cover this and implies in section 8.3 (page 
38 in my copy):
"In the case of several identical circuits, representative 
measurements (plural) on a selected number

of circuits may be sufficient. "
and further down:
"When testing line to ground, the lines are tested singly in sequence, 
if there is no other

specification."

From testing experience the only out we had for a client to test them 
all together (usually because they did not want to pay for individual 
testing) was if they were designed to be plugged into the same circuit 
breaker - which kind of defeats the purpose of having multiple cords. 
If you think about it if the cords are plugged into different circuits 
then the surge path to the individual cords can be different and you 
should not model it as equal on all cords - it could be out of phase 
as much as 180 degrees giving twice the surge across 2 cords. So 
keeping the other plugs at normal while the one cord is tested seems 
to be good practice.


My opinions only and not necessarily those of the company I work for



On Wed, Jan 2, 2019 at 3:35 PM John Woodgate > wrote:


Should you be testing a 'system' as a whole anyway? My take on
this is that if several pieces of equipment are invoiced together
with a single price for the lot, that is a system and all must be
tested together. But if the pieces are invoiced separately (so
that other equipment might be substituted for some in another
instance), that is not a system and the pieces should be tested
separately.

The authors of 61000-4-5 and 61326-x might well not have addressed
the case of multiple power cords. The test house 'advice' seems
reasonable, but it is not official and another test house might
offer other advice.

Best wishes
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associateswww.woodjohn.uk  
Rayleigh, Essex UK

On 2019-01-02 22:15, Larry K. Stillings wrote:


All,

I received the following email from a customer today via their
customer addressing our application of surge testing. We are
testing laboratory equipment per IEC/EN 61326-1 and IEC/EN
61326-2-6 and specifically are having failures with respect to
surge on a system that has multiple power cords. We are testing
one power cord at a time. Here are their comments

/we have never tested a system comprised of multiple instruments
in this way before. i.e. applying surge to one unit at a time –
we have always, with agreement from our customers, applied surge
(and in fact all tests) to all of the units plugged into e.g. a
mains distribution block all at the same time. Especially for
surge, it seems unlikely that in the real world any real surge on
the mains supply would not affect all things in a system as it is
very likely they are all plugged into the same mains circuit in
e.g a particular room. To further bolster this, we have made
comment to customers in the past that it could be noted in the
manual to ensure this is the case./

/ By applying surge to all units at the same time, we maintain
all of their supply voltages at the same level. I can see how, by
applying a surge to a single part of the wider system,
communications issues could occur as suddenly the points of
reference (i.e. reference voltages) for different parts of the
system could be pulled away from each other by the surge./

/Testing a system by applying the tests to all at once, rather
than a single item at a time, isn’t necessarily an “easy way out“
either. For other tests e.g. conducted emissions, where noise
transmitted from the unit under test back onto the mains supply
is measured, passing is made more difficult by measuring all
units at once. Where in this case one at a time would be much
more favourable. Our test house has always advised that we can
choose, either all tests one at a time, or all tests applied to
all through a mains block, but we cannot mix and match between
different sections for the conducted EMC tests./

I know this brings up all sorts of questions, however I would
like to focus on the surge testing at the moment. I am pretty
sure at least one of the standards says conducted emissions shall
be tested on each port individually, but we don’t need to go
there right now ;-)

Thoughts when you get responses like this?

Larry K. Stillings
Compliance Worldwide, Inc.
*/Test Locally, Sell Globally and Launch Your Products Around the
   

Re: [PSES] Red phosphorus flame retartants

[Scott Xe]

Hi Ted,

Many thanks for your sharing the anecdote!  I am also aware of a case on
mains cord sets.  It happened in 2014, 9 years after your case.  Two major
PC suppliers: Hx and Lenxxx recalled abt 7m mains cord sets globally
(details are in CPSC website).  It sounds not much lesson learnt.  National
Institute of Technology and Evaluation Technology in Japan did a
comprehensive investigation and published the results (the website in my
last email where you can find more detail).  Obviously, now more
electronics companies regulate and/or ban on red phosphorous flame
retardants due to long term safety issue rather than health and environment
under chemical regulation.  Is there any discussion in safety committees to
prevent it from recurrence?

Regards,

Scott

On Thu, 3 Jan 2019 at 07:40, Ted Eckert <
07cf6ebeab9d-dmarc-requ...@ieee.org> wrote:

> This is an anecdote and not data, but I can speak of the reliability issue
> from personal experience. I don’t remember exactly when this occurred, but
> it was around 2005. A supplier of power cords was using red phosphorus as
> the flame retardant in a plastic part for the IEC 60320-C13 connector on a
> power cord. The phosphorous was in the rigid plastic part that supported
> the contacts with the softer material molded over this material. The
> phosphorus was not well stabilized in the plastic. Moisture led to the
> chemical reaction described by Mr. Woodgate, resulting in phosphoric acid.
> The acid attached the contact material leading to a increase in the
> resistance of the contact. This occurred in products that used close to the
> full current rating of the connector, running close to 10 A. There was
> enough heating in the connector that the overmold material n the C13
> swelled up to the point where the connector could no longer be removed from
> the mating C14 connector.
>
>
>
> This did not cause a safety issue. Temperatures remained low enough that
> there was no ignition. This happened on industrial products in an
> environment where there were no flammable materials in the vicinity of the
> connectors. It only resulted in a reliability issue where there the
> electrical connection eventually was lost and the detachable cord was no
> longer detachable.
>
>
>
> The final analysis determined that the supplier of the plastic part using
> the phosphorous didn’t have sufficient quality control to ensure that the
> phosphorous was properly encapsulated. Supply chains have become more
> complicated since then. Quality control and supply chain management are
> critical to avoid similar issues.
>
>
>
> Ted Eckert
>
> Microsoft Corporation
>
>
>
> The opinions expressed are my own and do not necessarily reflect those of
> my current employer, previous employer or the manufactures or power cords
> and connectors.
>
>
>
> *From:* Adam Dixon 
> *Sent:* Wednesday, January 2, 2019 7:12 AM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* Re: [PSES] Red phosphorus flame retartants
>
>
>
> I agree that it's an older paper, but the data are still relevant IMO.
> Here are a few more recent ones from different US gov't organizations with
> a pyrology focus (so not solely focused on Scott's original question, but
> still informative):
>
>
>
> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5445781/
> 
>
>
>
> https://www.epa.gov/sites/production/files/2015-08/documents/pcb_ch1.pdf
> 
> (I think the EPA info has been shared on the list previously - just
> substitute 2 through 7 at the end of the URL to get all chapters).
>
>
>
> https://www.fire.tc.faa.gov/
> 
>
> https://www.fire.tc.faa.gov/pdf/05-14.pdf
> 
> (2005, so not quite as recent)
>
>
>
>
>
>
>
> Cheers,
>
> Adam in Atlanta
>
> adam.di...@ieee.org
>
>
>
>
>
>
>
> On Wed, Jan 2, 2019 at 2:31 AM John Woodgate  wrote:
>
> 

Re: [PSES] IEC 61000-4-5 Surge Testing Single plug vs. multiple plug system

[John Howe]

IEC 61000-4-5 (2005) does cover this and implies in section 8.3 (page 38 in
my copy):
"In the case of several identical circuits, representative measurements
(plural) on a selected number
of circuits may be sufficient. "
and further down:
"When testing line to ground, the lines are tested singly in sequence, if
there is no other
specification."

>From testing experience the only out we had for a client to test them all
together (usually because they did not want to pay for individual testing)
was if they were designed to be plugged into the same circuit breaker -
which kind of defeats the purpose of having multiple cords. If you think
about it if the cords are plugged into different circuits then the surge
path to the individual cords can be different and you should not model it
as equal on all cords - it could be out of phase as much as 180 degrees
giving twice the surge across 2 cords. So keeping the other plugs at normal
while the one cord is tested seems to be good practice.

My opinions only and not necessarily those of the company I work for



On Wed, Jan 2, 2019 at 3:35 PM John Woodgate  wrote:

> Should you be testing a 'system' as a whole anyway? My take on this is
> that if several pieces of equipment are invoiced together with a single
> price for the lot, that is a system and all must be tested together. But if
> the pieces are invoiced separately (so that other equipment might be
> substituted for some in another instance), that is not a system and the
> pieces should be tested separately.
>
> The authors of 61000-4-5 and 61326-x might well not have addressed the
> case of multiple power cords. The test house 'advice' seems reasonable, but
> it is not official and another test house might offer other advice.
>
> Best wishes
> John Woodgate OOO-Own Opinions Only
> J M Woodgate and Associates www.woodjohn.uk
> Rayleigh, Essex UK
>
> On 2019-01-02 22:15, Larry K. Stillings wrote:
>
> All,
>
>
>
> I received the following email from a customer today via their customer
> addressing our application of surge testing. We are testing laboratory
> equipment per IEC/EN 61326-1 and IEC/EN 61326-2-6 and specifically are
> having failures with respect to surge on a system that has multiple power
> cords. We are testing one power cord at a time. Here are their comments
>
>
>
> *we have never tested a system comprised of multiple instruments in this
> way before. i.e. applying surge to one unit at a time – we have always,
> with agreement from our customers, applied surge (and in fact all tests) to
> all of the units plugged into e.g. a mains distribution block all at the
> same time. Especially for surge, it seems unlikely that in the real world
> any real surge on the mains supply would not affect all things in a system
> as it is very likely they are all plugged into the same mains circuit in
> e.g a particular room. To further bolster this, we have made comment to
> customers in the past that it could be noted in the manual to ensure this
> is the case.*
>
>
>
> * By applying surge to all units at the same time, we maintain all of
> their supply voltages at the same level. I can see how, by applying a surge
> to a single part of the wider system, communications issues could occur as
> suddenly the points of reference (i.e. reference voltages) for different
> parts of the system could be pulled away from each other by the surge.*
>
>
>
> *Testing a system by applying the tests to all at once, rather than a
> single item at a time, isn’t necessarily an “easy way out“ either. For
> other tests e.g. conducted emissions, where noise transmitted from the unit
> under test back onto the mains supply is measured, passing is made more
> difficult by measuring all units at once. Where in this case one at a time
> would be much more favourable. Our test house has always advised that we
> can choose, either all tests one at a time, or all tests applied to all
> through a mains block, but we cannot mix and match between different
> sections for the conducted EMC tests.*
>
>
>
> I know this brings up all sorts of questions, however I would like to
> focus on the surge testing at the moment. I am pretty sure at least one of
> the standards says conducted emissions shall be tested on each port
> individually, but we don’t need to go there right now ;-)
>
>
>
> Thoughts when you get responses like this?
>
> Larry K. Stillings
> Compliance Worldwide, Inc.
> *Test Locally, Sell Globally and Launch Your Products Around the World!*
> *FCC - Wireless - Telecom - CE Marking - International Approvals - Product
> Safety*
> 357 Main Street
> Sandown, NH 03873
> (603) 887 3903 Fax 887-6445
> www.complianceworldwide.com
>
> Privileged/Confidential Information may be contained in this message. If
> you are not the addressee indicated in this message (or responsible for
> delivery of the message to such person), you may not copy or deliver this
> message to anyone. In such case, you should destroy this message and kindly
> 

Re: [PSES] Red phosphorus flame retartants

[Lauren Crane]

Ted,

Thanks for sharing this case study/anecdote. Very interesting.

Regards,
Lauren Crane
Tokyo Electron

From: Ted Eckert <07cf6ebeab9d-dmarc-requ...@ieee.org>
Sent: Wednesday, January 02, 2019 11:06 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Red phosphorus flame retartants

This is an anecdote and not data, but I can speak of the reliability issue from 
personal experience. I don’t remember exactly when this occurred, but it was 
around 2005. A supplier of power cords was using red phosphorus as the flame 
retardant in a plastic part for the IEC 60320-C13 connector on a power cord. 
The phosphorous was in the rigid plastic part that supported the contacts with 
the softer material molded over this material. The phosphorus was not well 
stabilized in the plastic. Moisture led to the chemical reaction described by 
Mr. Woodgate, resulting in phosphoric acid. The acid attached the contact 
material leading to a increase in the resistance of the contact. This occurred 
in products that used close to the full current rating of the connector, 
running close to 10 A. There was enough heating in the connector that the 
overmold material n the C13 swelled up to the point where the connector could 
no longer be removed from the mating C14 connector.

This did not cause a safety issue. Temperatures remained low enough that there 
was no ignition. This happened on industrial products in an environment where 
there were no flammable materials in the vicinity of the connectors. It only 
resulted in a reliability issue where there the electrical connection 
eventually was lost and the detachable cord was no longer detachable.

The final analysis determined that the supplier of the plastic part using the 
phosphorous didn’t have sufficient quality control to ensure that the 
phosphorous was properly encapsulated. Supply chains have become more 
complicated since then. Quality control and supply chain management are 
critical to avoid similar issues.

Ted Eckert
Microsoft Corporation

The opinions expressed are my own and do not necessarily reflect those of my 
current employer, previous employer or the manufactures or power cords and 
connectors.

From: Adam Dixon mailto:lanterna.viri...@gmail.com>>
Sent: Wednesday, January 2, 2019 7:12 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Red phosphorus flame retartants

I agree that it's an older paper, but the data are still relevant IMO.  Here 
are a few more recent ones from different US gov't organizations with a 
pyrology focus (so not solely focused on Scott's original question, but still 
informative):

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5445781/

https://www.epa.gov/sites/production/files/2015-08/documents/pcb_ch1.pdf
 (I think the EPA info has been shared on the list previously - just substitute 
2 through 7 at the end of the URL to get all chapters).

https://www.fire.tc.faa.gov/
https://www.fire.tc.faa.gov/pdf/05-14.pdf
  (2005, so not quite as recent)



Cheers,
Adam in Atlanta
adam.di...@ieee.org



On Wed, Jan 2, 2019 at 2:31 AM John Woodgate 
mailto:j...@woodjohn.uk>> wrote:

It is a good paper, but the sentence:

The European Union's risk assessment of TBBPA is currently ongoing and will not 
be completed until 2003 [9]

indicates that it is not exactly up-to-date.

Best wishes

John Woodgate OOO-Own Opinions Only

J M Woodgate and Associates 
www.woodjohn.uk

Rayleigh, Essex UK
On 2019-01-02 00:16, Adam 

Re: [PSES] Red phosphorus flame retartants

[Ted Eckert]

This is an anecdote and not data, but I can speak of the reliability issue from 
personal experience. I don’t remember exactly when this occurred, but it was 
around 2005. A supplier of power cords was using red phosphorus as the flame 
retardant in a plastic part for the IEC 60320-C13 connector on a power cord. 
The phosphorous was in the rigid plastic part that supported the contacts with 
the softer material molded over this material. The phosphorus was not well 
stabilized in the plastic. Moisture led to the chemical reaction described by 
Mr. Woodgate, resulting in phosphoric acid. The acid attached the contact 
material leading to a increase in the resistance of the contact. This occurred 
in products that used close to the full current rating of the connector, 
running close to 10 A. There was enough heating in the connector that the 
overmold material n the C13 swelled up to the point where the connector could 
no longer be removed from the mating C14 connector.

This did not cause a safety issue. Temperatures remained low enough that there 
was no ignition. This happened on industrial products in an environment where 
there were no flammable materials in the vicinity of the connectors. It only 
resulted in a reliability issue where there the electrical connection 
eventually was lost and the detachable cord was no longer detachable.

The final analysis determined that the supplier of the plastic part using the 
phosphorous didn’t have sufficient quality control to ensure that the 
phosphorous was properly encapsulated. Supply chains have become more 
complicated since then. Quality control and supply chain management are 
critical to avoid similar issues.

Ted Eckert
Microsoft Corporation

The opinions expressed are my own and do not necessarily reflect those of my 
current employer, previous employer or the manufactures or power cords and 
connectors.

From: Adam Dixon 
Sent: Wednesday, January 2, 2019 7:12 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Red phosphorus flame retartants

I agree that it's an older paper, but the data are still relevant IMO.  Here 
are a few more recent ones from different US gov't organizations with a 
pyrology focus (so not solely focused on Scott's original question, but still 
informative):

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5445781/

https://www.epa.gov/sites/production/files/2015-08/documents/pcb_ch1.pdf
 (I think the EPA info has been shared on the list previously - just substitute 
2 through 7 at the end of the URL to get all chapters).

https://www.fire.tc.faa.gov/
https://www.fire.tc.faa.gov/pdf/05-14.pdf
  (2005, so not quite as recent)



Cheers,
Adam in Atlanta
adam.di...@ieee.org



On Wed, Jan 2, 2019 at 2:31 AM John Woodgate 
mailto:j...@woodjohn.uk>> wrote:

It is a good paper, but the sentence:

The European Union's risk assessment of TBBPA is currently ongoing and will not 
be completed until 2003 [9]

indicates that it is not exactly up-to-date.

Best wishes

John Woodgate OOO-Own Opinions Only

J M Woodgate and Associates 
www.woodjohn.uk

Rayleigh, Essex UK
On 2019-01-02 00:16, Adam Dixon wrote:
Here's a good article focused on component reliability with some discussion of 
how red phosphorus is produced and comparison to several alternate fire 
retardant chemistries:

Re: [PSES] IEC 61000-4-5 Surge Testing Single plug vs. multiple plug system

[John Woodgate]

Should you be testing a 'system' as a whole anyway? My take on this is 
that if several pieces of equipment are invoiced together with a single 
price for the lot, that is a system and all must be tested together. But 
if the pieces are invoiced separately (so that other equipment might be 
substituted for some in another instance), that is not a system and the 
pieces should be tested separately.


The authors of 61000-4-5 and 61326-x might well not have addressed the 
case of multiple power cords. The test house 'advice' seems reasonable, 
but it is not official and another test house might offer other advice.


Best wishes
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates www.woodjohn.uk
Rayleigh, Essex UK

On 2019-01-02 22:15, Larry K. Stillings wrote:


All,

I received the following email from a customer today via their 
customer addressing our application of surge testing. We are testing 
laboratory equipment per IEC/EN 61326-1 and IEC/EN 61326-2-6 and 
specifically are having failures with respect to surge on a system 
that has multiple power cords. We are testing one power cord at a 
time. Here are their comments


/we have never tested a system comprised of multiple instruments in 
this way before. i.e. applying surge to one unit at a time – we have 
always, with agreement from our customers, applied surge (and in fact 
all tests) to all of the units plugged into e.g. a mains distribution 
block all at the same time. Especially for surge, it seems unlikely 
that in the real world any real surge on the mains supply would not 
affect all things in a system as it is very likely they are all 
plugged into the same mains circuit in e.g a particular room. To 
further bolster this, we have made comment to customers in the past 
that it could be noted in the manual to ensure this is the case./


/ By applying surge to all units at the same time, we maintain all of 
their supply voltages at the same level. I can see how, by applying a 
surge to a single part of the wider system, communications issues 
could occur as suddenly the points of reference (i.e. reference 
voltages) for different parts of the system could be pulled away from 
each other by the surge./


/Testing a system by applying the tests to all at once, rather than a 
single item at a time, isn’t necessarily an “easy way out“ either. For 
other tests e.g. conducted emissions, where noise transmitted from the 
unit under test back onto the mains supply is measured, passing is 
made more difficult by measuring all units at once. Where in this case 
one at a time would be much more favourable. Our test house has always 
advised that we can choose, either all tests one at a time, or all 
tests applied to all through a mains block, but we cannot mix and 
match between different sections for the conducted EMC tests./


I know this brings up all sorts of questions, however I would like to 
focus on the surge testing at the moment. I am pretty sure at least 
one of the standards says conducted emissions shall be tested on each 
port individually, but we don’t need to go there right now ;-)


Thoughts when you get responses like this?

Larry K. Stillings
Compliance Worldwide, Inc.
*/Test Locally, Sell Globally and Launch Your Products Around the World!/*
*/FCC - Wireless - Telecom - CE Marking - International Approvals - 
Product Safety/*

357 Main Street
Sandown, NH 03873
(603) 887 3903 Fax 887-6445
www.complianceworldwide.com 

Privileged/Confidential Information may be contained in this message. 
If you are not the addressee indicated in this message (or responsible 
for delivery of the message to such person), you may not copy or 
deliver this message to anyone. In such case, you should destroy this 
message and kindly notify the sender by reply email. Please advise 
immediately if you or your employer do not consent to Internet email 
for messages of this kind. Opinions, conclusions and other information 
in this message that do not relate to the official business of my firm 
shall be understood as neither given nor endorsed by it.




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Re: [PSES] IEC 61000-4-5 Surge Testing Single plug vs. multiple plug system

[Joe Randolph]

Hi Larry:

 

Are the failures do to actual damage, or just to upset?

 

I can imagine some situations where there might be upset for the
one-at-a-time configuration you describe, and I can understand how someone
might argue this configuration is not an appropriate test configuration.
However, I can't think of a valid reason why actual damage could be caused
when using this test configuration.

 

Also, during the one-at-a-time testing, how are the unused power cords
terminated?

 

Lastly, does the system perform its intended function when portions of the
system are unpowered?

 

Just some food for thought.

 

 

Joe Randolph

Telecom Design Consultant

Randolph Telecom, Inc.

781-721-2848 (USA)

  j...@randolph-telecom.com

  http://www.randolph-telecom.com

 

From: Larry K. Stillings [mailto:la...@complianceworldwide.com] 
Sent: Wednesday, January 02, 2019 5:16 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] IEC 61000-4-5 Surge Testing Single plug vs. multiple plug
system

 

All,

 

I received the following email from a customer today via their customer
addressing our application of surge testing. We are testing laboratory
equipment per IEC/EN 61326-1 and IEC/EN 61326-2-6 and specifically are
having failures with respect to surge on a system that has multiple power
cords. We are testing one power cord at a time. Here are their comments

 

we have never tested a system comprised of multiple instruments in this way
before. i.e. applying surge to one unit at a time - we have always, with
agreement from our customers, applied surge (and in fact all tests) to all
of the units plugged into e.g. a mains distribution block all at the same
time. Especially for surge, it seems unlikely that in the real world any
real surge on the mains supply would not affect all things in a system as it
is very likely they are all plugged into the same mains circuit in e.g a
particular room. To further bolster this, we have made comment to customers
in the past that it could be noted in the manual to ensure this is the case.

 

 By applying surge to all units at the same time, we maintain all of their
supply voltages at the same level. I can see how, by applying a surge to a
single part of the wider system, communications issues could occur as
suddenly the points of reference (i.e. reference voltages) for different
parts of the system could be pulled away from each other by the surge.

 

Testing a system by applying the tests to all at once, rather than a single
item at a time, isn't necessarily an "easy way out" either. For other tests
e.g. conducted emissions, where noise transmitted from the unit under test
back onto the mains supply is measured, passing is made more difficult by
measuring all units at once. Where in this case one at a time would be much
more favourable. Our test house has always advised that we can choose,
either all tests one at a time, or all tests applied to all through a mains
block, but we cannot mix and match between different sections for the
conducted EMC tests.

 

I know this brings up all sorts of questions, however I would like to focus
on the surge testing at the moment. I am pretty sure at least one of the
standards says conducted emissions shall be tested on each port
individually, but we don't need to go there right now ;-)

 

Thoughts when you get responses like this?

Larry K. Stillings
Compliance Worldwide, Inc. 
Test Locally, Sell Globally and Launch Your Products Around the World! 
FCC - Wireless - Telecom - CE Marking - International Approvals - Product
Safety 
357 Main Street
Sandown, NH 03873
(603) 887 3903 Fax 887-6445
www.complianceworldwide.com  

Privileged/Confidential Information may be contained in this message. If you
are not the addressee indicated in this message (or responsible for delivery
of the message to such person), you may not copy or deliver this message to
anyone. In such case, you should destroy this message and kindly notify the
sender by reply email. Please advise immediately if you or your employer do
not consent to Internet email for messages of this kind. Opinions,
conclusions and other information in this message that do not relate to the
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[PSES] IEC 61000-4-5 Surge Testing Single plug vs. multiple plug system

[Larry K. Stillings]

All,

 

I received the following email from a customer today via their customer
addressing our application of surge testing. We are testing laboratory
equipment per IEC/EN 61326-1 and IEC/EN 61326-2-6 and specifically are
having failures with respect to surge on a system that has multiple
power cords. We are testing one power cord at a time. Here are their
comments

 

we have never tested a system comprised of multiple instruments in this
way before. i.e. applying surge to one unit at a time - we have always,
with agreement from our customers, applied surge (and in fact all tests)
to all of the units plugged into e.g. a mains distribution block all at
the same time. Especially for surge, it seems unlikely that in the real
world any real surge on the mains supply would not affect all things in
a system as it is very likely they are all plugged into the same mains
circuit in e.g a particular room. To further bolster this, we have made
comment to customers in the past that it could be noted in the manual to
ensure this is the case.

 

 By applying surge to all units at the same time, we maintain all of
their supply voltages at the same level. I can see how, by applying a
surge to a single part of the wider system, communications issues could
occur as suddenly the points of reference (i.e. reference voltages) for
different parts of the system could be pulled away from each other by
the surge.

 

Testing a system by applying the tests to all at once, rather than a
single item at a time, isn't necessarily an "easy way out" either. For
other tests e.g. conducted emissions, where noise transmitted from the
unit under test back onto the mains supply is measured, passing is made
more difficult by measuring all units at once. Where in this case one at
a time would be much more favourable. Our test house has always advised
that we can choose, either all tests one at a time, or all tests applied
to all through a mains block, but we cannot mix and match between
different sections for the conducted EMC tests.

 

I know this brings up all sorts of questions, however I would like to
focus on the surge testing at the moment. I am pretty sure at least one
of the standards says conducted emissions shall be tested on each port
individually, but we don't need to go there right now ;-)

 

Thoughts when you get responses like this?

Larry K. Stillings
Compliance Worldwide, Inc. 
Test Locally, Sell Globally and Launch Your Products Around the World! 
FCC - Wireless - Telecom - CE Marking - International Approvals -
Product Safety 
357 Main Street
Sandown, NH 03873
(603) 887 3903 Fax 887-6445
www.complianceworldwide.com  

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Re: [PSES] Red phosphorus flame retartants

[Adam Dixon]

I agree that it's an older paper, but the data are still relevant IMO.
Here are a few more recent ones from different US gov't organizations with
a pyrology focus (so not solely focused on Scott's original question, but
still informative):

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5445781/

https://www.epa.gov/sites/production/files/2015-08/documents/pcb_ch1.pdf (I
think the EPA info has been shared on the list previously - just substitute
2 through 7 at the end of the URL to get all chapters).

https://www.fire.tc.faa.gov/
https://www.fire.tc.faa.gov/pdf/05-14.pdf  (2005, so not quite as recent)



Cheers,
Adam in Atlanta
adam.di...@ieee.org



On Wed, Jan 2, 2019 at 2:31 AM John Woodgate  wrote:

> It is a good paper, but the sentence:
>
> *The European Union's risk assessment of TBBPA is currently ongoing and
> will not be completed until 2003 [9]*
>
> indicates that it is not exactly up-to-date.
>
> Best wishes
> John Woodgate OOO-Own Opinions Only
> J M Woodgate and Associates www.woodjohn.uk
> Rayleigh, Essex UK
>
> On 2019-01-02 00:16, Adam Dixon wrote:
>
> Here's a good article focused on component reliability with some
> discussion of how red phosphorus is produced and comparison to several
> alternate fire retardant chemistries:
>
>
> https://www.dfrsolutions.com/red-phosphorus-induced-failures-in-encapsulated-circuits
>
>
> Cheers,
> Adam in Atlanta
> adam.di...@ieee.org
>
>
>
> On Tue, Jan 1, 2019 at 5:46 PM John Woodgate  wrote:
>
>> Well, there wouldn't be any mention of white phosphorus, of course,
>> because that would indicate that the technique is not safe at all. I just
>> wonder how they stop it happening; it appears to be just a mechanical
>> envelopment by the polyamide (e.g. Nylon).  If so, prolonged moderate
>> heating over several years might cause migration and subsequent conversion
>> to the other allotrope at surfaces.
>>
>> The BASF document is quite informative:
>> *In a report by the German Federal Environment Agency, it is stated that
>> the red phosphorus used in polymers can only be released into the
>> environment at the plastic interfaces, where it reacts with water to form
>> phosphorus oxides and** phosphoric acids.*
>>
>> Actually, it's a two-step process; first we get oxidation: 4P +3O2 >2P2O3,
>> then the trioxide dissolves in water to make 'phosphorous acid' (the quotes
>> are because it exists in two forms with different formal chemical names).
>>
>> I just hope that this isn't another case like CFCs, where a highly
>> undesirable effect was not recognized until it became serious.  The
>> Wikipedia article on allotropes of phosphorus says:
>>
>>   *However, for electronic/electrical systems, red phosphorus flame
>> retardant has been effectively banned by major OEMs due to its tendency to
>> induce premature failures. There have been two issues over the years: the
>> first was red phosphorus in epoxy molding compounds inducing elevated
>> leakage current in semiconductor devices[5] and the second was acceleration
>> of hydrolysis reactions in PBT insulating material.*
>>
>> I think that's a wrap!
>>
>> Best wishes
>> John Woodgate OOO-Own Opinions Only
>> J M Woodgate and Associates www.woodjohn.uk
>> Rayleigh, Essex UK
>>
>> On 2019-01-01 21:24, Richard Nute wrote:
>>
>>
>>
>> If the hype is true, and my interpretation is correct, red phosphorous as
>> a flame-retardant additive is much better than bromine-based additives.  I
>> don’t know of cost differential.  (In the two websites I looked at, there
>> was no mention of degradation to white phosphorus.)
>>
>>
>>
>> BASF:
>> https://www.plasticsportal.net/wa/plasticsEU~en_GB/function/conversions:/publish/common/upload/technical_journals/electronics_and_mechatronics/Umwuchtsensor.pdf
>>
>>
>>
>> Rinka:
>> http://www.rinka.co.jp/english/products/flame-retardant/index.html
>>
>>
>>
>> Best wishes for the New Year,
>>
>> Rich
>>
>>
>>
>>
>>
>>
>>
>>
>> -
>> 
>>
>> This message is from the IEEE Product Safety Engineering Society emc-pstc
>> discussion list. To post a message to the list, send your e-mail to <
>> emc-p...@ieee.org>
>>
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>> 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/
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>>
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