Re: [PSES] hipot test

[Pete Perkins]

Doug,You are correct in that the issues we are dealing with are a part of 
the Low Voltage installation (up to 600Vac and 1000Vdc in North America, higher 
in Europe) wherein all of the common equipment resides.  

 

   Having been a part of the US/TAG to IEC SC28A and now IEC 109 
technical committees I am quite familiar with Insulation Coordination in Low 
Voltage equipment.  

 

   The issues are exacerbated with voltage.  Medium voltage 
distribution (about 12kV to 75kV or so) has its own issues and Hi Voltage 
transmission (above 75kV to 1MV here in the US) even more issues.  The IEEE 
transactions on Dielectrics have continuously dealt with these issues over the 
years.  Hopefully you have tried to keep up. 

 

   Dr Klaus Stemper, as chairman, brought technical discipline to 
the work resulting in substantial improvement in the IEC 60664 series (it was 
one volume when I started).  It also brought a lot of complexity which the 
follow-on teams have tried to again simplify for ease of use.  

 

   Thanx for the chance to reminisce.  

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

IEEE Life Fellow

  p.perk...@ieee.org

 

From: Doug Powell  
Sent: Wednesday, August 15, 2018 1:40 PM
To: Pete Perkins ; EMC-PSTC 
Subject: Re: [PSES] hipot test

 

Pete,

 

Your statements may be true for many product types certified to 60950-1, 
61010-1, etc.  However when dealing with power conversion products that have 
secondary voltages well above mains voltages, this is no longer true.  In the 
region of 5,000 V and above, corona is a common occurrence in inhomogeneous 
fields and this has the effect of causing surface damage (carbonization) on 
insulation with any organic content.  Inorganic insulators such as ceramics and 
glass seem to be much less affected.  

 

Such phenomena is mentioned in Klaus Stimper's book, The Physical Fundamentals 
of Low-Voltage Insulation Co-ordination.

 

All the best,  Doug

 

 

 

On Wed, Aug 15, 2018 at 10:04 AM Pete Perkins 
<0061f3f32d0c-dmarc-requ...@ieee.org 
 > wrote:

All, This discussion goes around  year after year.  

 

   The test results reported – especially Nute – show that it takes 
dozens, maybe  hundreds of hipot tests to damage adequate insulation.  

 

   In the UK, so I hear, the gov’t safety folks expect each piece 
of equipment to be hipot retested annually to demonstrate adequate insulation.  
We don’t hear a large hue and cry about failing equipment in that arena.  

 

   So from the experience and the data it is clear that both the 
engineering type hipot testing and the factory routine testing should not pose 
any problem to properly designed and manufactured products.  

 

   For line connected products it is foolishness to remove 
components for hipot testing.  If that is being done the product is not robust 
enough in the first place.  This includes DC line powered equipment since so 
much DC power is being installed and used in places where it is subject to the 
same lighting and starting impulses traditionally seen on AC line operated 
equipment.   

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

IEEE Life Fellow

  p.perk...@ieee.org

 

From: Jim Hulbert mailto:jim.hulb...@pb.com> > 
Sent: Wednesday, August 15, 2018 5:25 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] hipot test

 

I disagree with your NRTL.  If the hipot test can degrade the insulation (we’re 
talking about a single test on the production line), then the insulation system 
is not up to par.  

 

Jim


 

 

From: Nyffenegger, Dave [mailto:dave.nyffeneg...@bhemail.com] 
Sent: Wednesday, August 15, 2018 12:18 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] hipot test

 

The NRTL I typically use always runs the hipot test for 60 seconds for type 
testing during product certification.  The listing reports always specify a 1 
second hipot for production line testing 100% of all units.  Their claim is 
that the hipot can degrade some insulation and should be kept to a minimum.

 

-Dave

 

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Tuesday, August 14, 2018 5:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] hipot test

 

 

Hi Doug:

 

I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification. 

 

I disagree.  The hi-pot test determines the minimum electric strength of the 
insulation system.  Design is an indirect mea

Re: [PSES] hipot test

[Doug Smith]

Hi Doug and the Group,

In the case of my 48 Volt fire years ago, it was local heating from a power 
resistor that turned the FR-4 conductive and then the 48VDC flowing through 
that area created more heat and then positive feedback took over with negative 
results.

DougUniversity of Oxford, Course Tutor
Department for Continuing Education
Oxford, Oxfordshire, United Kingdom
--
Doug Smith
P.O. Box 60941
Boulder City, NV 89006-0941
TEL/FAX: 702-570-6108/570-6013
Mobile: 408-858-4528
Email: d...@dsmith.org
Web: http://www.dsmith.org
--





On Wed, 15 Aug 2018 14:39:36 -0600, Doug Powell  wrote:
 Pete,
 
Your statements may be true for many product types certified to 60950-1, 
61010-1, etc.  However when dealing with power conversion products that have 
secondary voltages well above mains voltages, this is no longer true.  In the 
region of 5,000 V and above, corona is a common occurrence in inhomogeneous 
fields and this has the effect of causing surface damage (carbonization) on 
insulation with any organic content.  Inorganic insulators such as ceramics and 
glass seem to be much less affected.  
 
Such phenomena is mentioned in Klaus Stimper's book, The Physical Fundamentals 
of Low-Voltage Insulation Co-ordination.
 
All the best,  Doug
 
 
 On Wed, Aug 15, 2018 at 10:04 AM Pete Perkins 
<0061f3f32d0c-dmarc-requ...@ieee.org> wrote:
All, This discussion goes around  year after year. 
 
   The test results reported – especially Nute – show 
that it takes dozens, maybe  hundreds of hipot tests to damage adequate 
insulation. 
 
   In the UK, so I hear, the gov’t safety folks expect 
each piece of equipment to be hipot retested annually to demonstrate adequate 
insulation.  We don’t hear a large hue and cry about failing equipment in that 
arena. 
 
   So from the experience and the data it is clear that 
both the engineering type hipot testing and the factory routine testing should 
not pose any problem to properly designed and manufactured products. 
 
   For line connected products it is foolishness to 
remove components for hipot testing.  If that is being done the product is not 
robust enough in the first place.  This includes DC line powered equipment 
since so much DC power is being installed and used in places where it is 
subject to the same lighting and starting impulses traditionally seen on AC 
line operated equipment.   
 
:>)  br,  Pete
 
Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 23427
Tigard, ORe  97281-3427
 
503/452-1201
 
IEEE Life Fellow
p.perk...@ieee.org

 
From:
 Jim Hulbert 
Sent:
 Wednesday, August 15, 2018 5:25 AM
To:
 EMC-PSTC@LISTSERV.IEEE.ORG

Subject: Re: [PSES] hipot test

 
I disagree with your NRTL.  If the hipot test can degrade the insulation (we’re 
talking about a single test on the production line), then the insulation system 
is not up to par.  
 
Jim
 


 
From:
 Nyffenegger, Dave [mailto:dave.nyffeneg...@bhemail.com
]
Sent:
 Wednesday, August 15, 2018 12:18 AM
To:
 EMC-PSTC@LISTSERV.IEEE.ORG

Subject: Re: [PSES] hipot test

 
The NRTL I typically use always runs the hipot test for 60 seconds for type 
testing during product certification.  The listing reports always specify a 1 
second hipot for production line testing 100% of all units.  Their claim is 
that the hipot can degrade some insulation and should be kept to a minimum.
 
-Dave
 
From:
 Richard Nute [mailto:ri...@ieee.org
]
Sent:
 Tuesday, August 14, 2018 5:34 PM
To:
 EMC-PSTC@LISTSERV.IEEE.ORG

Subject: [PSES] hipot test

 
 
Hi Doug:
 
I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification. 
 
I disagree.  The hi-pot test determines the minimum electric strength of the 
insulation system.  Design is an indirect measure of electric strength by 
selecting the distances through solid and air (clearance) insulations.  
However, design rarely includes the shape of the electric field, which is a 
parameter that determines electric strength.  
 
Since hipot is so stressful to insulation…
 
Again, I disagree.  If the design is “good” (adequate electric strength), then 
the hi-pot test does not stress the insulation system.  See Agilent 
Technologies Optocoupler Input-Output Endurance Voltage Application Note 1074.
 
Best regards,
Rich
 
 
 
From:
 Doug Powell 
Sent:
 Tuesday, August 14, 2018 1:50 PM
To:
 EMC-PSTC@LISTSERV.IEEE.ORG

Subject: Re: [PSES] X & Y Cap rating due to hipot test
 
I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification.  During routine testing 
for manufacturing, it is workmanship and build verification.  

 

During type testing many safety standards will ask for hipot verificati

Re: [PSES] circuit boards

[Doug Smith]

Hi Rich and the group,

I have seen FR-4 become conductive, start the board on fire, and burn up a rack 
of equipment! In that case the driving voltage was 48 VDC. Never let both sides 
of power come close on a board if heating can happen in the vicinity.

Of course, here in Boulder City, NV heating happens all the time. No need to 
warm up the car engine, it already is. Also, we have unlimited solar hot water 
from the cold water faucetI have become used to it, and at 71 years old, I 
still run miles and miles at 110 degrees at a brisk pace in the strong sun 
(along with a lot of younger people out here).
 


Doug Smith
University of Oxford, Course Tutor
Department for Continuing Education
Oxford, Oxfordshire, United Kingdom
--
Doug Smith
P.O. Box 60941
Boulder City, NV 89006-0941
TEL/FAX: 702-570-6108/570-6013
Mobile: 408-858-4528
Email: d...@dsmith.org
Web: http://www.dsmith.org
--
 





On Wed, 15 Aug 2018 13:09:54 -0700, Richard Nute  wrote:






 

My experience with circuit boards and plastics is that some formulations 
degrade with heat (pyrolysis) to a resistive state.  I have a C14 
appliance inlet that has been overheated and I can measure the (cold) 
resistance with an ohmmeter (even today, some years after the incident).  
Same for printed wiring boards.  

 

When solid insulation becomes a resistor, all kinds of heating (and fire) can 
occur.  

 

Best regards,

Rich

IEEE Life Fellow

 

 



From: Pete Perkins <0061f3f32d0c-dmarc-requ...@ieee.org>
Sent: Wednesday, August 15, 2018 12:29 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test



 

John,     your description sounds much like the failure 
mechanism seen is circuit boards which start in a small void and develop 
micro-arcing which feeds upon itself and eventually drives a large void that 
allows conductors to directly contribute current and destroy the board.  
I’ve investigated some destructive fires in equipment from such a source. And 
the circuit boards don’t need full hipot voltages to do this, line operated 
units eat themselves up quite handily.   

  
 No, I don’t mean to start anew thread here.  

 


:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

IEEE Life Fellow

p.perk...@ieee.org


 

-

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-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] hipot test

[Doug Powell]

Pete,

Your statements may be true for many product types certified to 60950-1,
61010-1, etc.  However when dealing with power conversion products that
have secondary voltages well above mains voltages, this is no longer true.
In the region of 5,000 V and above, corona is a common occurrence in
inhomogeneous fields and this has the effect of causing surface damage
(carbonization) on insulation with any organic content.  Inorganic
insulators such as ceramics and glass seem to be much less affected.

Such phenomena is mentioned in Klaus Stimper's book, The Physical
Fundamentals of Low-Voltage Insulation Co-ordination.

All the best,  Doug



On Wed, Aug 15, 2018 at 10:04 AM Pete Perkins <
0061f3f32d0c-dmarc-requ...@ieee.org> wrote:

> All, This discussion goes around  year after year.
>
>
>
>The test results reported – especially Nute – show that it
> takes dozens, maybe  hundreds of hipot tests to damage adequate
> insulation.
>
>
>
>In the UK, so I hear, the gov’t safety folks expect each
> piece of equipment to be hipot retested annually to demonstrate adequate
> insulation.  We don’t hear a large hue and cry about failing equipment in
> that arena.
>
>
>
>So from the experience and the data it is clear that both
> the engineering type hipot testing and the factory routine testing should
> not pose any problem to properly designed and manufactured products.
>
>
>
>For line connected products it is foolishness to remove
> components for hipot testing.  If that is being done the product is not
> robust enough in the first place.  This includes DC line powered equipment
> since so much DC power is being installed and used in places where it is
> subject to the same lighting and starting impulses traditionally seen on AC
> line operated equipment.
>
>
>
> :>) br,  Pete
>
>
>
> Peter E Perkins, PE
>
> Principal Product Safety & Regulatory Affairs Consultant
>
> PO Box 23427
>
> Tigard, ORe  97281-3427
>
>
>
> 503/452-1201
>
>
>
> IEEE Life Fellow
>
> p.perk...@ieee.org
>
>
>
> *From:* Jim Hulbert 
> *Sent:* Wednesday, August 15, 2018 5:25 AM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* Re: [PSES] hipot test
>
>
>
> I disagree with your NRTL.  If the hipot test can degrade the insulation
> (we’re talking about a single test on the production line), then the
> insulation system is not up to par.
>
>
>
> Jim
>
>
>
>
>
> *From:* Nyffenegger, Dave [mailto:dave.nyffeneg...@bhemail.com
> ]
> *Sent:* Wednesday, August 15, 2018 12:18 AM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* Re: [PSES] hipot test
>
>
>
> The NRTL I typically use always runs the hipot test for 60 seconds for
> type testing during product certification.  The listing reports always
> specify a 1 second hipot for production line testing 100% of all units.
> Their claim is that the hipot can degrade some insulation and should be
> kept to a minimum.
>
>
>
> -Dave
>
>
>
> *From:* Richard Nute [mailto:ri...@ieee.org ]
> *Sent:* Tuesday, August 14, 2018 5:34 PM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* [PSES] hipot test
>
>
>
>
>
> Hi Doug:
>
>
>
> I've always viewed the purpose of hipot testing as verification only.
> During engineering type testing, it is design verification.
>
>
>
> I disagree.  The hi-pot test determines the minimum electric strength of
> the insulation system.  Design is an indirect measure of electric strength
> by selecting the distances through solid and air (clearance) insulations.
> However, design rarely includes the shape of the electric field, which is a
> parameter that determines electric strength.
>
>
>
> Since hipot is so stressful to insulation…
>
>
>
> Again, I disagree.  If the design is “good” (adequate electric strength),
> then the hi-pot test does not stress the insulation system.  See Agilent
> Technologies Optocoupler Input-Output Endurance Voltage Application Note
> 1074.
>
>
>
> Best regards,
>
> Rich
>
>
>
>
>
>
>
> *From:* Doug Powell 
> *Sent:* Tuesday, August 14, 2018 1:50 PM
> *To:* EMC-PSTC@LISTSERV.IEEE.ORG
> *Subject:* Re: [PSES] X & Y Cap rating due to hipot test
>
>
>
> I've always viewed the purpose of hipot testing as verification only.
> During engineering type testing, it is design verification.  During routine
> testing for manufacturing, it is workmanship and build verification.
>
>
>
> During type testing many safety standards will ask for hipot verification
> at various stages, after thermal/humidity tests, after abnormal operations,
> etc.  Since hipot is so stressful to insulation, it is possible to
> introduce latent failures in the test sample after performing multiple
> hipot tests, combining many hipots into one is allowable by many
> inspectors.
>
>
>
> During routine testing, a brief hipot is added at the end of the
> manufacturing cycle to ensure wire routing is correct (spacings are
> maintained), integrity of insulation is maintained, in cases where
> vibration testing is involved a test

[PSES] circuit boards

[Richard Nute]

 

My experience with circuit boards and plastics is that some formulations 
degrade with heat (pyrolysis) to a resistive state.  I have a C14 appliance 
inlet that has been overheated and I can measure the (cold) resistance with an 
ohmmeter (even today, some years after the incident).  Same for printed wiring 
boards.  

 

When solid insulation becomes a resistor, all kinds of heating (and fire) can 
occur.  

 

Best regards,

Rich

IEEE Life Fellow

 

 

From: Pete Perkins <0061f3f32d0c-dmarc-requ...@ieee.org> 
Sent: Wednesday, August 15, 2018 12:29 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test

 

John, your description sounds much like the failure mechanism seen is 
circuit boards which start in a small void and develop micro-arcing which feeds 
upon itself and eventually drives a large void that allows conductors to 
directly contribute current and destroy the board.  I’ve investigated some 
destructive fires in equipment from such a source. And the circuit boards don’t 
need full hipot voltages to do this, line operated units eat themselves up 
quite handily.   

   No, I don’t mean to start anew thread here.  

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

IEEE Life Fellow

  p.perk...@ieee.org

 


-

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] hipot test

[John Woodgate]

It was bureaucratic and inflexible, because unofficial, alarmist 
interpretations spread like a Californian fire, opening up routes for 
criminal exploitation. After a while it got so bad that senior people at 
the Health and Safety Executive (HSE) had to step in and stop the rot. 
Unfortunately, much of what was done was 'commercially sensitive', so 
not disclosed, but there are HSE 'idiot's guides' on the web, and some 
more detailed guidance that is not free of charge.


Abuses included 'testing' wood and plastic enclosures (for a fee, of 
course), and damaging equipment with the hi-pot output and quoting huge 
fees for repairing. In fact, legitimate repair was often totally 
uneconomic.


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

On 2018-08-15 20:22, Pete Perkins wrote:


John, thanx for your note on this.  I’m not surprised that the WWW is 
wooly on this subject.  My sources for this are from my experience – 
with my former employer who had two UK shops producing products and 
had to deal with this issue as well as feedback from clients that I 
have had along the way in my consultancy who were caught up in this 
issue.  In either case it all seemed to be quite bureaucratic and 
inflexible when it got to the factory floor during HSW inspections.


:>) br,  Pete

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

503/452-1201

IEEE Life Fellow

p.perk...@ieee.org 

*From:*John Woodgate 
*Sent:* Wednesday, August 15, 2018 12:14 PM
*To:* Pete Perkins ; EMC-PSTC@LISTSERV.IEEE.ORG
*Subject:* Re: [PSES] hipot test

in the UK, the requirements are in fact very woolly, and it's 
difficult to find definitive information on the Web. But testing 
doesn't have to be done annually, and hi-pot only in cases of repair 
of hired-out equipment.  Unfortunately, insulation resistance testing, 
with PASS values even below 1 megohm in some cases, is included.


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

On 2018-08-15 17:03, Pete Perkins wrote:

All, This discussion goes around year after year.

   The test results reported – especially Nute – show
that it takes dozens, maybe hundreds of hipot tests to damage
adequate insulation.

   In the UK, so I hear, the gov’t safety folks expect
each piece of equipment to be hipot retested annually to
demonstrate adequate insulation.  We don’t hear a large hue and
cry about failing equipment in that arena.

   So from the experience and the data it is clear
that both the engineering type hipot testing and the factory
routine testing should not pose any problem to properly designed
and manufactured products.

   For line connected products it is foolishness to
remove components for hipot testing.  If that is being done the
product is not robust enough in the first place.  This includes DC
line powered equipment since so much DC power is being installed
and used in places where it is subject to the same lighting and
starting impulses traditionally seen on AC line operated equipment.

:>) br,  Pete




-

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] hipot test

[John Woodgate]

Yes, it's more or less the same effect. Repeated surface discharges 
across contaminated thermosetting plastics also caused carbonization, 
often resulting in a fireworks display when the mains voltage was 
applied after testing.


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

On 2018-08-15 20:29, Pete Perkins wrote:


John, your description sounds much like the failure mechanism seen is 
circuit boards which start in a small void and develop micro-arcing 
which feeds upon itself and eventually drives a large void that allows 
conductors to directly contribute current and destroy the board.  I’ve 
investigated some destructive fires in equipment from such a source. 
And the circuit boards don’t need full hipot voltages to do this, line 
operated units eat themselves up quite handily.


No, I don’t mean to start anew thread here.

:>) br,  Pete

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

503/452-1201

IEEE Life Fellow

p.perk...@ieee.org 

*From:*John Woodgate 
*Sent:* Wednesday, August 15, 2018 12:17 PM
*To:* EMC-PSTC@LISTSERV.IEEE.ORG
*Subject:* Re: [PSES] hipot test

I think it's not quite like that. Modern insulating materials don't 
degrade, but old ones did, or at least appeared to. For instance, 
oiled paper had pinholes, and a discharge caused local carbonization, 
which prompted more discharges and more carbonization.


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

On 2018-08-15 18:07, Richard Nute wrote:

Their claim is that the hipot can degrade some insulation and
should be kept to a minimum.

Conventional wisdom not supported by science.

Best regards,

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 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)
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>>
David Heald mailto:dhe...@gmail.com>>

-


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

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>>
David Heald mailto:dhe...@gmail.com>>

-


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

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>>
David Heald mailto:dhe...@gmail.com>>




-

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

All emc-pstc p

Re: [PSES] hipot test

[Pete Perkins]

John, your description sounds much like the failure mechanism seen is 
circuit boards which start in a small void and develop micro-arcing which feeds 
upon itself and eventually drives a large void that allows conductors to 
directly contribute current and destroy the board.  I’ve investigated some 
destructive fires in equipment from such a source. And the circuit boards don’t 
need full hipot voltages to do this, line operated units eat themselves up 
quite handily.   

   No, I don’t mean to start anew thread here.  

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

IEEE Life Fellow

  p.perk...@ieee.org

 

From: John Woodgate  
Sent: Wednesday, August 15, 2018 12:17 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test

 

I think it's not quite like that. Modern insulating materials don't degrade, 
but old ones did, or at least appeared to. For instance, oiled paper had 
pinholes, and a discharge caused local carbonization, which prompted more 
discharges and more carbonization.

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

On 2018-08-15 18:07, Richard Nute wrote:

 

Their claim is that the hipot can degrade some insulation and should be kept to 
a minimum.

 

Conventional wisdom not supported by science.

 

Best regards,

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 
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) 
 
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> >
David Heald mailto:dhe...@gmail.com> > 

 

-


This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
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) 
 
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> >
David Heald mailto:dhe...@gmail.com> > 


-

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


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

[Pete Perkins]

John, thanx for your note on this.  I’m not surprised that the WWW is wooly 
on this subject.  My sources for this are from my experience – with my former 
employer who had two UK shops producing products and had to deal with this 
issue as well as feedback from clients that I have had along the way in my 
consultancy who were caught up in this issue.  In either case it all seemed to 
be quite bureaucratic and inflexible when it got to the factory floor during 
HSW inspections.  

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

IEEE Life Fellow

  p.perk...@ieee.org

 

From: John Woodgate  
Sent: Wednesday, August 15, 2018 12:14 PM
To: Pete Perkins ; EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test

 

in the UK, the requirements are in fact very woolly, and it's difficult to find 
definitive information on the Web. But testing doesn't have to be done 
annually, and hi-pot only in cases of repair of hired-out equipment.  
Unfortunately, insulation resistance testing, with PASS values even below 1 
megohm in some cases, is included.

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

On 2018-08-15 17:03, Pete Perkins wrote:

All, This discussion goes around  year after year.  

 

   The test results reported – especially Nute – show that it takes 
dozens, maybe  hundreds of hipot tests to damage adequate insulation.  

 

   In the UK, so I hear, the gov’t safety folks expect each piece 
of equipment to be hipot retested annually to demonstrate adequate insulation.  
We don’t hear a large hue and cry about failing equipment in that arena.  

 

   So from the experience and the data it is clear that both the 
engineering type hipot testing and the factory routine testing should not pose 
any problem to properly designed and manufactured products.  

 

   For line connected products it is foolishness to remove 
components for hipot testing.  If that is being done the product is not robust 
enough in the first place.  This includes DC line powered equipment since so 
much DC power is being installed and used in places where it is subject to the 
same lighting and starting impulses traditionally seen on AC line operated 
equipment.   

 

:>) br,  Pete

 


 

 

 

 


-

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] hipot test

[John Woodgate]

I think it's not quite like that. Modern insulating materials don't 
degrade, but old ones did, or at least appeared to. For instance, oiled 
paper had pinholes, and a discharge caused local carbonization, which 
prompted more discharges and more carbonization.


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

On 2018-08-15 18:07, Richard Nute wrote:


Their claim is that the hipot can degrade some insulation and should 
be kept to a minimum.


Conventional wisdom not supported by science.

Best regards,

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 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)

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>>
David Heald mailto:dhe...@gmail.com>>




-

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

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

[John Woodgate]

in the UK, the requirements are in fact very woolly, and it's difficult 
to find definitive information on the Web. But testing doesn't have to 
be done annually, and hi-pot only in cases of repair of hired-out 
equipment.  Unfortunately, insulation resistance testing, with PASS 
values even below 1 megohm in some cases, is included.


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

On 2018-08-15 17:03, Pete Perkins wrote:


All, This discussion goes around year after year.

   The test results reported – especially Nute – show that 
it takes dozens, maybe  hundreds of hipot tests to damage adequate 
insulation.


   In the UK, so I hear, the gov’t safety folks expect 
each piece of equipment to be hipot retested annually to demonstrate 
adequate insulation.  We don’t hear a large hue and cry about failing 
equipment in that arena.


   So from the experience and the data it is clear that 
both the engineering type hipot testing and the factory routine 
testing should not pose any problem to properly designed and 
manufactured products.


   For line connected products it is foolishness to remove 
components for hipot testing.  If that is being done the product is 
not robust enough in the first place.  This includes DC line powered 
equipment since so much DC power is being installed and used in places 
where it is subject to the same lighting and starting impulses 
traditionally seen on AC line operated equipment.


:>) br,  Pete





-

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] hipot test

[Richard Nute]

 

Hi Ken:

 

If the dc lines are subject to lightning, e.g., solar panels, then
transients can exist on the dc line.

 

If the dc powers several equipments, then switching transients can exist on
the dc line.  The more equipment is connected to the dc, the more switching
transients.  

 

In both situations, the transient voltages are likely to be microseconds
duration.  

 

Best regards,

Rich

 

 

From: Ken Javor  
Sent: Wednesday, August 15, 2018 9:34 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test

 

There is a huge difference between a transient lasting microseconds and a dc
application. The cap will load (to some extent) a transient, but it can't
load dc.

Ken Javor
Phone: (256) 650-5261





-

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] hipot test

[Richard Nute]

 

 

If the hipot test can degrade the insulation (we’re talking about a single test 
on the production line), then the insulation system is not up to par. 

 

Good point!

 

Best regards,

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 


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] hipot test

[Richard Nute]

 

Their claim is that the hipot can degrade some insulation and should be kept to 
a minimum.

 

Conventional wisdom not supported by science.

 

Best regards,

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 


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] hipot test

[Pete Perkins]

Ken,   I agree.  But there is a lot of equipment being provided in a DC
operated environment where the nuisance transients exist.  I'm thinking, for
instance, of Solar and Wind-power installations which are often remote and
self-power all of the control and transmission equipment off of the exposed
internal DC power.  Hence my statement.  

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

IEEE Life Fellow

  p.perk...@ieee.org

 

From: Ken Javor  
Sent: Wednesday, August 15, 2018 9:34 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test

 

There is a huge difference between a transient lasting microseconds and a dc
application. The cap will load (to some extent) a transient, but it can't
load dc.

Ken Javor
Phone: (256) 650-5261




  _  

From: Pete Perkins <0061f3f32d0c-dmarc-requ...@ieee.org
 >
Reply-To: Pete Perkins mailto:peperkin...@cs.com> >
Date: Wed, 15 Aug 2018 09:03:57 -0700
To: mailto:EMC-PSTC@LISTSERV.IEEE.ORG> >
Subject: Re: [PSES] hipot test

All, This discussion goes around  year after year.  
 
   The test results reported - especially Nute - show that it
takes dozens, maybe  hundreds of hipot tests to damage adequate insulation.

 
   In the UK, so I hear, the gov't safety folks expect each
piece of equipment to be hipot retested annually to demonstrate adequate
insulation.  We don't hear a large hue and cry about failing equipment in
that arena.  
 
   So from the experience and the data it is clear that both the
engineering type hipot testing and the factory routine testing should not
pose any problem to properly designed and manufactured products.  
 
   For line connected products it is foolishness to remove
components for hipot testing.  If that is being done the product is not
robust enough in the first place.  This includes DC line powered equipment
since so much DC power is being installed and used in places where it is
subject to the same lighting and starting impulses traditionally seen on AC
line operated equipment.   
 

:>) br,  Pete
 
Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 23427
Tigard, ORe  97281-3427
 
503/452-1201
 
IEEE Life Fellow
p.perk...@ieee.org    
 
 

From: Jim Hulbert mailto:jim.hulb...@pb.com> > 
Sent: Wednesday, August 15, 2018 5:25 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] hipot test
 
I disagree with your NRTL.  If the hipot test can degrade the insulation
(we're talking about a single test on the production line), then the
insulation system is not up to par.  
 
Jim



From: Nyffenegger, Dave [mailto:dave.nyffeneg...@bhemail.com] 
Sent: Wednesday, August 15, 2018 12:18 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] hipot test
 
The NRTL I typically use always runs the hipot test for 60 seconds for type
testing during product certification.  The listing reports always specify a
1 second hipot for production line testing 100% of all units.  Their claim
is that the hipot can degrade some insulation and should be kept to a
minimum.
 
-Dave
 

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Tuesday, August 14, 2018 5:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] hipot test

 
Hi Doug:
 
I've always viewed the purpose of hipot testing as verification only.
During engineering type testing, it is design verification. 

I disagree.  The hi-pot test determines the minimum electric strength of the
insulation system.  Design is an indirect measure of electric strength by
selecting the distances through solid and air (clearance) insulations.
However, design rarely includes the shape of the electric field, which is a
parameter that determines electric strength.  
 
Since hipot is so stressful to insulation.

Again, I disagree.  If the design is "good" (adequate electric strength),
then the hi-pot test does not stress the insulation system.  See Agilent
Technologies Optocoupler Input-Output Endurance Voltage Application Note
1074.
 
Best regards,
Rich
 
 
 
From: Doug Powell mailto:doug...@gmail.com> > 
Sent: Tuesday, August 14, 2018 1:50 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] X & Y Cap rating due to hipot test
 

I've always viewed the purpose of hipot testing as verification only.
During engineering type testing, it is design verification.  During routine
testing for manufacturing, it is workmanship and build verification.  



During type testing many safety standards will ask for hipot verification at
various stages, after thermal/humidity tests, after abnormal operations,
etc.  

Re: [PSES] hipot test

[Ken Javor]

There is a huge difference between a transient lasting microseconds and a dc
application. The cap will load (to some extent) a transient, but it can¹t
load dc.

Ken Javor
Phone: (256) 650-5261




From: Pete Perkins <0061f3f32d0c-dmarc-requ...@ieee.org>
Reply-To: Pete Perkins 
Date: Wed, 15 Aug 2018 09:03:57 -0700
To: 
Subject: Re: [PSES] hipot test

All, This discussion goes around  year after year. 
 
   The test results reported ­ especially Nute ­ show that it
takes dozens, maybe  hundreds of hipot tests to damage adequate insulation. 
 
   In the UK, so I hear, the gov¹t safety folks expect each
piece of equipment to be hipot retested annually to demonstrate adequate
insulation.  We don¹t hear a large hue and cry about failing equipment in
that arena.  
 
   So from the experience and the data it is clear that both the
engineering type hipot testing and the factory routine testing should not
pose any problem to properly designed and manufactured products. 
 
   For line connected products it is foolishness to remove
components for hipot testing.  If that is being done the product is not
robust enough in the first place.  This includes DC line powered equipment
since so much DC power is being installed and used in places where it is
subject to the same lighting and starting impulses traditionally seen on AC
line operated equipment.   
 

:>) br,  Pete
 
Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 23427
Tigard, ORe  97281-3427
 
503/452-1201
 
IEEE Life Fellow
p.perk...@ieee.org 
 

From: Jim Hulbert 
Sent: Wednesday, August 15, 2018 5:25 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test
 
I disagree with your NRTL.  If the hipot test can degrade the insulation
(we¹re talking about a single test on the production line), then the
insulation system is not up to par.
 
Jim
 
 

From: Nyffenegger, Dave [mailto:dave.nyffeneg...@bhemail.com]
Sent: Wednesday, August 15, 2018 12:18 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test
 
The NRTL I typically use always runs the hipot test for 60 seconds for type
testing during product certification.  The listing reports always specify a
1 second hipot for production line testing 100% of all units.  Their claim
is that the hipot can degrade some insulation and should be kept to a
minimum.
 
-Dave
 

From: Richard Nute [mailto:ri...@ieee.org]
Sent: Tuesday, August 14, 2018 5:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] hipot test
 
 
Hi Doug:
 
I've always viewed the purpose of hipot testing as verification only.
During engineering type testing, it is design verification.
 
I disagree.  The hi-pot test determines the minimum electric strength of the
insulation system.  Design is an indirect measure of electric strength by
selecting the distances through solid and air (clearance) insulations.
However, design rarely includes the shape of the electric field, which is a
parameter that determines electric strength.
 
Since hipot is so stressful to insulationŠ
 
Again, I disagree.  If the design is ³good² (adequate electric strength),
then the hi-pot test does not stress the insulation system.  See Agilent
Technologies Optocoupler Input-Output Endurance Voltage Application Note
1074.
 
Best regards,
Rich
 
 
 
From: Doug Powell 
Sent: Tuesday, August 14, 2018 1:50 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] X & Y Cap rating due to hipot test
 

I've always viewed the purpose of hipot testing as verification only.
During engineering type testing, it is design verification.  During routine
testing for manufacturing, it is workmanship and build verification.

 

During type testing many safety standards will ask for hipot verification at
various stages, after thermal/humidity tests, after abnormal operations,
etc.  Since hipot is so stressful to insulation, it is possible to introduce
latent failures in the test sample after performing multiple hipot tests,
combining many hipots into one is allowable by many inspectors.

 

During routine testing, a brief hipot is added at the end of the
manufacturing cycle to ensure wire routing is correct (spacings are
maintained), integrity of insulation is maintained, in cases where vibration
testing is involved a test for chafing of wire insulation and so on.  Most
safety standards have provision for "allowable disconnects" during the hipot
such as surge suppressors and the like.  Also, hipot of sub-assemblies in
lieu of the finished assembly if it can be shown that the test is
representative.  

 

Best to all, Doug

 

-- 

 
Douglas E Powell

doug...@gmail.com
http://www.linkedin.com/in/dougp01

 
-

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

Re: [PSES] hipot test

[Pete Perkins]

All, This discussion goes around  year after year.  

 

   The test results reported – especially Nute – show that it takes 
dozens, maybe  hundreds of hipot tests to damage adequate insulation.  

 

   In the UK, so I hear, the gov’t safety folks expect each piece 
of equipment to be hipot retested annually to demonstrate adequate insulation.  
We don’t hear a large hue and cry about failing equipment in that arena.  

 

   So from the experience and the data it is clear that both the 
engineering type hipot testing and the factory routine testing should not pose 
any problem to properly designed and manufactured products.  

 

   For line connected products it is foolishness to remove 
components for hipot testing.  If that is being done the product is not robust 
enough in the first place.  This includes DC line powered equipment since so 
much DC power is being installed and used in places where it is subject to the 
same lighting and starting impulses traditionally seen on AC line operated 
equipment.   

 

:>) br,  Pete

 

Peter E Perkins, PE

Principal Product Safety & Regulatory Affairs Consultant

PO Box 23427

Tigard, ORe  97281-3427

 

503/452-1201

 

IEEE Life Fellow

  p.perk...@ieee.org

 

From: Jim Hulbert  
Sent: Wednesday, August 15, 2018 5:25 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test

 

I disagree with your NRTL.  If the hipot test can degrade the insulation (we’re 
talking about a single test on the production line), then the insulation system 
is not up to par.  

 

Jim


 

 

From: Nyffenegger, Dave [mailto:dave.nyffeneg...@bhemail.com] 
Sent: Wednesday, August 15, 2018 12:18 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] hipot test

 

The NRTL I typically use always runs the hipot test for 60 seconds for type 
testing during product certification.  The listing reports always specify a 1 
second hipot for production line testing 100% of all units.  Their claim is 
that the hipot can degrade some insulation and should be kept to a minimum.

 

-Dave

 

From: Richard Nute [mailto:ri...@ieee.org] 
Sent: Tuesday, August 14, 2018 5:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: [PSES] hipot test

 

 

Hi Doug:

 

I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification. 

 

I disagree.  The hi-pot test determines the minimum electric strength of the 
insulation system.  Design is an indirect measure of electric strength by 
selecting the distances through solid and air (clearance) insulations.  
However, design rarely includes the shape of the electric field, which is a 
parameter that determines electric strength.  

 

Since hipot is so stressful to insulation…

 

Again, I disagree.  If the design is “good” (adequate electric strength), then 
the hi-pot test does not stress the insulation system.  See Agilent 
Technologies Optocoupler Input-Output Endurance Voltage Application Note 1074.

 

Best regards,

Rich

 

 

 

From: Doug Powell mailto:doug...@gmail.com> > 
Sent: Tuesday, August 14, 2018 1:50 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG  
Subject: Re: [PSES] X & Y Cap rating due to hipot test

 

I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification.  During routine testing 
for manufacturing, it is workmanship and build verification.  

 

During type testing many safety standards will ask for hipot verification at 
various stages, after thermal/humidity tests, after abnormal operations, etc.  
Since hipot is so stressful to insulation, it is possible to introduce latent 
failures in the test sample after performing multiple hipot tests, combining 
many hipots into one is allowable by many inspectors.  

 

During routine testing, a brief hipot is added at the end of the manufacturing 
cycle to ensure wire routing is correct (spacings are maintained), integrity of 
insulation is maintained, in cases where vibration testing is involved a test 
for chafing of wire insulation and so on.  Most safety standards have provision 
for "allowable disconnects" during the hipot such as surge suppressors and the 
like.  Also, hipot of sub-assemblies in lieu of the finished assembly if it can 
be shown that the test is representative.  

 

Best to all, Doug

 

-- 

 

Douglas E Powell

doug...@gmail.com  
http://www.linkedin.com/in/dougp01

 

-


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

[PSES] TUV SUD RF Test Engineer opening - Raleigh Durham N.C.

[Mac Elliott]

Colleagues, 
TUV SUD America is looking for an experienced RF / Wireless Test Engineer for 
its RTP Test Lab. 
Below is a link to the Indeed job posting sent to me by the lab manager. 
https://www.indeed.com/viewjob?jk=db51de01ad1ba5e2&tk=1ckv0eesr53l88be&from=vjnewtab

Thanks and have a great day
Best regards, 
Mac Elliott

-

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] hipot test

[Jim Hulbert]

I disagree with your NRTL.  If the hipot test can degrade the insulation (we’re 
talking about a single test on the production line), then the insulation system 
is not up to par.

Jim



From: Nyffenegger, Dave [mailto:dave.nyffeneg...@bhemail.com]
Sent: Wednesday, August 15, 2018 12:18 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] hipot test

The NRTL I typically use always runs the hipot test for 60 seconds for type 
testing during product certification.  The listing reports always specify a 1 
second hipot for production line testing 100% of all units.  Their claim is 
that the hipot can degrade some insulation and should be kept to a minimum.

-Dave

From: Richard Nute [mailto:ri...@ieee.org]
Sent: Tuesday, August 14, 2018 5:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] hipot test


Hi Doug:

I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification.

I disagree.  The hi-pot test determines the minimum electric strength of the 
insulation system.  Design is an indirect measure of electric strength by 
selecting the distances through solid and air (clearance) insulations.  
However, design rarely includes the shape of the electric field, which is a 
parameter that determines electric strength.

Since hipot is so stressful to insulation…

Again, I disagree.  If the design is “good” (adequate electric strength), then 
the hi-pot test does not stress the insulation system.  See Agilent 
Technologies Optocoupler Input-Output Endurance Voltage Application Note 1074.

Best regards,
Rich



From: Doug Powell mailto:doug...@gmail.com>>
Sent: Tuesday, August 14, 2018 1:50 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] X & Y Cap rating due to hipot test

I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification.  During routine testing 
for manufacturing, it is workmanship and build verification.

During type testing many safety standards will ask for hipot verification at 
various stages, after thermal/humidity tests, after abnormal operations, etc.  
Since hipot is so stressful to insulation, it is possible to introduce latent 
failures in the test sample after performing multiple hipot tests, combining 
many hipots into one is allowable by many inspectors.

During routine testing, a brief hipot is added at the end of the manufacturing 
cycle to ensure wire routing is correct (spacings are maintained), integrity of 
insulation is maintained, in cases where vibration testing is involved a test 
for chafing of wire insulation and so on.  Most safety standards have provision 
for "allowable disconnects" during the hipot such as surge suppressors and the 
like.  Also, hipot of sub-assemblies in lieu of the finished assembly if it can 
be shown that the test is representative.

Best to all, Doug

--

Douglas E Powell

doug...@gmail.com
http://www.linkedin.com/in/dougp01

-


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)
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>>
David Heald mailto:dhe...@gmail.com>>
-


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

Re: [PSES] hipot test

[Nyffenegger, Dave]

The NRTL I typically use always runs the hipot test for 60 seconds for type 
testing during product certification.  The listing reports always specify a 1 
second hipot for production line testing 100% of all units.  Their claim is 
that the hipot can degrade some insulation and should be kept to a minimum.

-Dave

From: Richard Nute [mailto:ri...@ieee.org]
Sent: Tuesday, August 14, 2018 5:34 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] hipot test


Hi Doug:

I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification.

I disagree.  The hi-pot test determines the minimum electric strength of the 
insulation system.  Design is an indirect measure of electric strength by 
selecting the distances through solid and air (clearance) insulations.  
However, design rarely includes the shape of the electric field, which is a 
parameter that determines electric strength.

Since hipot is so stressful to insulation…

Again, I disagree.  If the design is “good” (adequate electric strength), then 
the hi-pot test does not stress the insulation system.  See Agilent 
Technologies Optocoupler Input-Output Endurance Voltage Application Note 1074.

Best regards,
Rich



From: Doug Powell 
Sent: Tuesday, August 14, 2018 1:50 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] X & Y Cap rating due to hipot test

I've always viewed the purpose of hipot testing as verification only.  During 
engineering type testing, it is design verification.  During routine testing 
for manufacturing, it is workmanship and build verification.

During type testing many safety standards will ask for hipot verification at 
various stages, after thermal/humidity tests, after abnormal operations, etc.  
Since hipot is so stressful to insulation, it is possible to introduce latent 
failures in the test sample after performing multiple hipot tests, combining 
many hipots into one is allowable by many inspectors.

During routine testing, a brief hipot is added at the end of the manufacturing 
cycle to ensure wire routing is correct (spacings are maintained), integrity of 
insulation is maintained, in cases where vibration testing is involved a test 
for chafing of wire insulation and so on.  Most safety standards have provision 
for "allowable disconnects" during the hipot such as surge suppressors and the 
like.  Also, hipot of sub-assemblies in lieu of the finished assembly if it can 
be shown that the test is representative.

Best to all, Doug

--

Douglas E Powell

doug...@gmail.com
http://www.linkedin.com/in/dougp01

-


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)
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>>
David Heald mailto:dhe...@gmail.com>>

-

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


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