Re: [PSES] Routine Test 60950-1, 62368-1

[IBM Ken]

Hi Kurt!
My apologies; I imagined your situation as being a 19" rack with various
units (1U servers, network switches, etc) plugging to one or more PDUs.

There are some mechanical tricks you can do to mitigate the long-screw
problem, but it sounds like your product is already well past the design
phase.  Is there an Agency requesting that you (re)do hipot testing at the
system level, or are you just thinking about if it is required from a
safety (and liability) standpoint?

-Ken A

On Sun, Sep 3, 2017 at 4:20 PM, Kurt Beneder  wrote:

> Dear Ken
>
> its a 19 inch rack mountable product with a backplane and several
> submodule plug-in pcb's.
> It has a metall case for mounting it into a 19 inch rack.
> From the protection class point of view its a class I (protection earth)
> product.
> Good point regarding assembly failures and wiring failures. We will
> performing an analysis and document it.
>
> My argument for not doing an isolation test on the assembled system is
> that it will test only solid insulation which is allready tested at subunit
> level.
> Maybe screws which are fallen in can be detected with that test.
>
> I want to render the argument pointless which states that one can detect a
> clearance distance violation due e.g. too long screws with such test.
> Verification of clearances uses much higher test voltages which depends on
> the height above sea level.
> The hipot test is also done with voltage levels which tests the solid
> insulation and not the clearances.
>
> Best regards
> Kurt Beneder
>
>
> On Sun, Sep 3, 2017 at 6:10 PM, IBM Ken  wrote:
>
>> Hi Kurt!
>> At the system (end product level);
>>
>> -Do you add a PDU and plug on the manufacturing line and plug all the
>> modules into it?
>> -Do you have small screws, wires, etc which are used to assemble the end
>> product which might fall into the product?
>> -Do you have any opportunity for miswiring/misplugging?
>>
>> In most cases, it's a good idea to hipot the assembly as a complete
>> product at the end of the manufacturing line.  It is not usually required
>> to re-do each module hipot test separately, but rather just once at the
>> Mains input (but I don't know the construction of your product).
>>
>> Regarding your comment about height above sea level;  the hipot test is
>> based on the working voltage and the maximum operating altitude as designed
>> (it is not dependent on the actual altitude of the factory).
>>
>> -Ken A
>>
>>
>> On Sun, Sep 3, 2017 at 11:28 AM, Kurt Beneder 
>> wrote:
>>
>>> Hi all,
>>>
>>> i am defining the routine tests for a 19 inch Rack System according to
>>> IEC 60950-1 and IEC 62368-1.
>>> We test routinely the solid insulation of each submodule during
>>> production.
>>> The final system is variable, so some modules are sometimes in the
>>> system or not, depending on the configuration from the customer.
>>>
>>> The question for me is wether a routine test of the solid insulation of
>>> the final product is still necessary.
>>> Especially if one has many circuits with hazardous voltages (relais
>>> contacts, power supply, other hazardous voltage outputs) which increases
>>> the test effort.
>>>
>>> As far as i know the test voltages applied according the standards are
>>> for verification of solid insulation only.
>>> This is done in our case at the subassembly level: every circuit against
>>> every other circuit of the submodule
>>> So the argument sometimes that we have to retest the whole device for
>>> verification of the clearances,
>>> which could be compromised during assembly of the final product, is not
>>> valid for me
>>> as this would require much different and higher voltage levels dependent
>>> on the height above sea level of the test site.
>>>
>>> What is your opinion?
>>>
>>> Best regards
>>>
>>> Kurt Beneder
>>> -
>>> 
>>>
>>> This message is from the IEEE Product Safety Engineering Society
>>> emc-pstc discussion list. To post a message to the list, send your e-mail
>>> to emc-p...@ieee.org
>>>
>>> All emc-pstc postings are archived and searchable on the web at:
>>> http://www.ieee-pses.org/emc-pstc.html
>>>
>>> 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 sdoug...@ieee.org
>>> Mike Cantwell mcantw...@ieee.org
>>>
>>> For policy questions, send mail to:
>>> Jim Bacher j.bac...@ieee.org
>>> David Heald dhe...@gmail.com
>>>
>>
>>
> -
> 
>
> This message is 

[PSES] Why higher value for DC in SELV - Electrical Shock Safety Criteria"

[mickm]

At http://www.sciencedirect.com/science/article/pii/B9780080253992500187 
I found


Electrical Shock Safety Criteria

Proceedings of the First International Symposium on Electrical Shock 
Safety Criteria


1985, Pages 173–181

DYNAMIC ASPECTS OF BODY IMPEDANCE

Richard Nute

Tektronix, Inc., Beaverton, Oregon

Available online 17 November 2013

ABSTRACT

This paper describes a group of experiments conducted on humans to 
determine physiological factors that attend the onset of electrical 
shock sensation including how body resistance varies as a function of 
the potential and frequency of an applied voltage. The unique test setup 
employed is fully explained and diagrammed, experimental techniques are 
described, and several X-Y plots, where each point on the resultant 
curve represents instantaneous body resistance, are included. Data from 
this investigation suggests that: 1) for some portions of the human 
body, impedance is a function of both applied voltage level and the 
duration of its application; and 2) at a particular voltage level there 
is an apparent sudden decrease in skin impedance (increase in current) 
coincident with the onset of (the sensation of) electrical shock.


The PDF file purchase price is $31.50

Other proceedings papers are listed papers are also listed.





Regards,

Mick Maytum

Safety and Telecom
Standards

mjmay...@gmail.com

https://ictsp-essays.info


-- Original Message --
From: "Richard Nute" 
To: EMC-PSTC@listserv.ieee.org
Sent: 03/09/2017 21:15:21
Subject: Re: [PSES] Why higher value for DC in SELV




Hi Vincent:



As far as I know, the papers in "Electrical Shock Safety Criteria" have 
never been available in electronic form.  I don’t have a copy except 
the hard-copy book as it was well before electronic storage was common.




Best regards,

Richard Nute





From: Vincent Lee [mailto:ntueeestud...@yahoo.com]
Sent: Sunday, September 03, 2017 2:06 AM
To: Richard Nute 
Subject: Re: [PSES] Why higher value for DC in SELV



Richard,



Good morning

Thank you very much for the reply.



May I know can you kindly provide the article that you published, 
"Electrical Shock Safety Criteria," edited by J.E. Bridges, Pergamon 
Press, 1985 because I was not able to access it after much Internet 
search ?




Lastly, what are the difference between electrical shock and electrical 
burn? Do they have the same safety criteria ?




Once again, thank you a lot

Regards, Vincent


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Re: [PSES] Routine Test 60950-1, 62368-1

[John Woodgate]

Ah, I thought you were asking about a rack of different products, not a single 
rack-mountable product with plug-ins. It's very unusual, I think, to 
routine-test subunits. But you could do that, and also test the unpopulated 
enclosure. The usual way of eliminating the 'long screw' issue is to ensure 
that even the longest screw the standard considers cannot cause a violation.
 
With best wishes DESIGN IT IN! OOO – Own Opinions Only
  www.jmwa.demon.co.uk J M Woodgate and 
Associates Rayleigh England
 
UK is a sovereignty, not a Zollverein-ty
 
From: Kurt Beneder [mailto:kurt.bene...@ieee.org] 
Sent: Sunday, September 3, 2017 9:20 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Routine Test 60950-1, 62368-1
 
Dear Ken
its a 19 inch rack mountable product with a backplane and several submodule 
plug-in pcb's.
It has a metall case for mounting it into a 19 inch rack.
>From the protection class point of view its a class I (protection earth) 
>product.
Good point regarding assembly failures and wiring failures. We will performing 
an analysis and document it.
 
My argument for not doing an isolation test on the assembled system is that it 
will test only solid insulation which is allready tested at subunit level.
Maybe screws which are fallen in can be detected with that test.
 
I want to render the argument pointless which states that one can detect a 
clearance distance violation due e.g. too long screws with such test.
Verification of clearances uses much higher test voltages which depends on the 
height above sea level.
The hipot test is also done with voltage levels which tests the solid 
insulation and not the clearances.
 
Best regards 
Kurt Beneder
 
 
On Sun, Sep 3, 2017 at 6:10 PM, IBM Ken  > wrote:
Hi Kurt!
At the system (end product level);
 
-Do you add a PDU and plug on the manufacturing line and plug all the modules 
into it?
-Do you have small screws, wires, etc which are used to assemble the end 
product which might fall into the product?
-Do you have any opportunity for miswiring/misplugging?
 
In most cases, it's a good idea to hipot the assembly as a complete product at 
the end of the manufacturing line.  It is not usually required to re-do each 
module hipot test separately, but rather just once at the Mains input (but I 
don't know the construction of your product). 
 
Regarding your comment about height above sea level;  the hipot test is based 
on the working voltage and the maximum operating altitude as designed (it is 
not dependent on the actual altitude of the factory).
 
-Ken A
 
 
On Sun, Sep 3, 2017 at 11:28 AM, Kurt Beneder  > wrote:
Hi all,
i am defining the routine tests for a 19 inch Rack System according to IEC 
60950-1 and IEC 62368-1.
We test routinely the solid insulation of each submodule during production.
The final system is variable, so some modules are sometimes in the system or 
not, depending on the configuration from the customer.
The question for me is wether a routine test of the solid insulation of the 
final product is still necessary.
Especially if one has many circuits with hazardous voltages (relais contacts, 
power supply, other hazardous voltage outputs) which increases the test effort.
As far as i know the test voltages applied according the standards are for 
verification of solid insulation only.
This is done in our case at the subassembly level: every circuit against every 
other circuit of the submodule
So the argument sometimes that we have to retest the whole device for 
verification of the clearances, 
which could be compromised during assembly of the final product, is not valid 
for me 
as this would require much different and higher voltage levels dependent on the 
height above sea level of the test site.
What is your opinion?
Best regards
Kurt Beneder
-

This message is from the IEEE Product Safety Engineering Society emc-pstc 
discussion list. To post a message to the list, send your e-mail to 
emc-p...@ieee.org  
All emc-pstc postings are archived and searchable on the web at: 
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Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.
Website: http://www.ieee-pses.org/
Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 
 
List rules: http://www.ieee-pses.org/listrules.html 
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David Heald dhe...@gmail.com   
 
 
-

Re: [PSES] Routine Test 60950-1, 62368-1

[Kurt Beneder]

Dear Ken

its a 19 inch rack mountable product with a backplane and several submodule
plug-in pcb's.
It has a metall case for mounting it into a 19 inch rack.
>From the protection class point of view its a class I (protection earth)
product.
Good point regarding assembly failures and wiring failures. We will
performing an analysis and document it.

My argument for not doing an isolation test on the assembled system is that
it will test only solid insulation which is allready tested at subunit
level.
Maybe screws which are fallen in can be detected with that test.

I want to render the argument pointless which states that one can detect a
clearance distance violation due e.g. too long screws with such test.
Verification of clearances uses much higher test voltages which depends on
the height above sea level.
The hipot test is also done with voltage levels which tests the solid
insulation and not the clearances.

Best regards
Kurt Beneder


On Sun, Sep 3, 2017 at 6:10 PM, IBM Ken  wrote:

> Hi Kurt!
> At the system (end product level);
>
> -Do you add a PDU and plug on the manufacturing line and plug all the
> modules into it?
> -Do you have small screws, wires, etc which are used to assemble the end
> product which might fall into the product?
> -Do you have any opportunity for miswiring/misplugging?
>
> In most cases, it's a good idea to hipot the assembly as a complete
> product at the end of the manufacturing line.  It is not usually required
> to re-do each module hipot test separately, but rather just once at the
> Mains input (but I don't know the construction of your product).
>
> Regarding your comment about height above sea level;  the hipot test is
> based on the working voltage and the maximum operating altitude as designed
> (it is not dependent on the actual altitude of the factory).
>
> -Ken A
>
>
> On Sun, Sep 3, 2017 at 11:28 AM, Kurt Beneder 
> wrote:
>
>> Hi all,
>>
>> i am defining the routine tests for a 19 inch Rack System according to
>> IEC 60950-1 and IEC 62368-1.
>> We test routinely the solid insulation of each submodule during
>> production.
>> The final system is variable, so some modules are sometimes in the system
>> or not, depending on the configuration from the customer.
>>
>> The question for me is wether a routine test of the solid insulation of
>> the final product is still necessary.
>> Especially if one has many circuits with hazardous voltages (relais
>> contacts, power supply, other hazardous voltage outputs) which increases
>> the test effort.
>>
>> As far as i know the test voltages applied according the standards are
>> for verification of solid insulation only.
>> This is done in our case at the subassembly level: every circuit against
>> every other circuit of the submodule
>> So the argument sometimes that we have to retest the whole device for
>> verification of the clearances,
>> which could be compromised during assembly of the final product, is not
>> valid for me
>> as this would require much different and higher voltage levels dependent
>> on the height above sea level of the test site.
>>
>> What is your opinion?
>>
>> Best regards
>>
>> Kurt Beneder
>> -
>> 
>>
>> This message is from the IEEE Product Safety Engineering Society emc-pstc
>> discussion list. To post a message to the list, send your e-mail to 
>> emc-p...@ieee.org
>>
>> All emc-pstc postings are archived and searchable on the web at:
>> http://www.ieee-pses.org/emc-pstc.html
>>
>> 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 sdoug...@ieee.org
>> Mike Cantwell mcantw...@ieee.org
>>
>> For policy questions, send mail to:
>> Jim Bacher j.bac...@ieee.org
>> David Heald dhe...@gmail.com
>>
>
>

-

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discussion list. To post a message to the list, send your e-mail to 


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http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
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Re: [PSES] Why higher value for DC in SELV

[Richard Nute]

 

Hi Vincent:

 

As far as I know, the papers in "Electrical Shock Safety Criteria" have never 
been available in electronic form.  I don’t have a copy except the hard-copy 
book as it was well before electronic storage was common.  

 

Best regards,

Richard Nute

 

 

From: Vincent Lee [mailto:ntueeestud...@yahoo.com] 
Sent: Sunday, September 03, 2017 2:06 AM
To: Richard Nute 
Subject: Re: [PSES] Why higher value for DC in SELV

 

Richard,

 

Good morning

Thank you very much for the reply. 

 

May I know can you kindly provide the article that you published, "Electrical 
Shock Safety Criteria," edited by J.E. Bridges, Pergamon Press, 1985 because I 
was not able to access it after much Internet search ?

 

Lastly, what are the difference between electrical shock and electrical burn? 
Do they have the same safety criteria ?

 

Once again, thank you a lot

Regards, Vincent


-

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


All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

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

Website:  http://www.ieee-pses.org/
Instructions:  http://www.ieee-pses.org/list.html (including how to unsubscribe)
List rules: http://www.ieee-pses.org/listrules.html

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Scott Douglas 
Mike Cantwell 

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

Re: [PSES] Why higher value for DC in SELV

[John Allen]

Hi Rich,

Very well stated, as always.  Your contributions to our industry will forever 
be appreciated.

Thank you and Best Regards,

John

John Allen
Product Safety Consulting, Inc
www.productsafetyinc.com

On Sep 2, 2017, at 3:47 PM, Richard Nute 
> wrote:



Hi Pete and Vincent:

While the body is susceptible to current, the body resistance changes (lowers) 
as a function of voltage.  At voltages below 30 volts (DC or AC peak), the body 
impedance is very much greater (orders of magnitude) than the 1500-ohm value 
specified in IEC 60990.

Consider, if the body impedance was always 1500 ohms, then a 1.5-volt battery 
would give 1 mA body current.  We all know that this isn't the case.

I have done a number of experiments applying a slowly rising (1 minute) voltage 
(from a voltage source) from zero to 30 to the palm and forearm.  Large contact 
area.  The voltage and current were shown on an oscilloscope.  The body 
resistance could then be calculated from the voltage and current at any 
specific time.   The body resistance changes to a lower value, dramatically, as 
the voltage approaches 30.  I published the results in "Electrical Shock Safety 
Criteria," edited by J.E. Bridges, Pergamon Press, 1985.  I have repeated the 
test in many of my HBSE classes, and the results remain the same.  The voltage 
and time of dramatic lowering of body impedance is a function of applied 
voltage, duration, and the individual.

Where the "prospective voltage" exceeds the low-voltage limit, the current must 
be limited.  There is no current limit if the voltage is below the low-voltage 
limit value.

Because the body impedance is a function of voltage, low voltages, regardless 
of source current, are considered "safe" by most authorities.

The values of 30 volts AC and 60 volts DC are traditional, but have since been 
rationalized in IEC 61201.  The body responses to AC and DC current are 
described in IEC 60479.  The body response to AC is at a lower current than DC. 
 Hence, 30 volts AC and 60 volts DC.  And 0.5 mA AC and 2 mA DC.

For electric shock conditions, both voltage and current must exceed specified 
values.  If *either* voltage or current does not exceed specified values, then 
conditions for electric shock does not exist and safety is assured.

Best regards,
Richard Nute


On 9/2/2017 7:10 AM, Pete Perkins wrote:
Vincent,

The issue of adequate electric shock protection is difficult in 
that the human body responds to current rather than voltage.  This was quickly 
discovered by the early workers, such as Dalziel in the USA, and has been 
incorporated in the IEC work in the 60479 series of standards dealing with the 
effects of current on the human body.

IEC 60479-1 and 60479-2 deal directly with these currents.  The 
long term limit for LETGO-IMMOBILIZATION is 5mArms/7.1mApeak for bipolar/AC and 
25Ma for monopolar/DC.  More current is allowed at higher frequencies/shorter 
times as shown in the accompanying curves in these standards.  Note that I have 
expanded the waveform description to more easily allow you to see how it is 
implemented for non-sinusoidal waveforms which are much more important these 
days for switching electronics such as SMPS, VSDs and CFL/LED lamps.

Voltage has been used as a proxy for current since the early 
days because it has always been easier to measure voltage.  Because different 
historical limits have been used at various times and in various places there 
is some variation as to which voltage limits constitute adequate protection.   
The case for choosing the correct voltage limits to provide the same protection 
is much more complicated and needs to be modified to include the contact 
conditions and body impedance variations.  It is covered in IEC 61201 and 
60479-5 which contain dozens of curves for a myriad of these conditions.

The addition of switching electronics has brought about 
additional scrutiny for proper electric shock protection.  The development of 
IEC 60990 brings the needed focus on making proper TOUCH CURRENT measurements 
in products today, focusing on making peak measurements of these pulse driven 
non-sinusoidal waveforms.  Product standards, starting with IEC 60950 and 61010 
have worked to implement these methods and they are being further implemented 
in other product standards (and need to be more fully implemented further as 
electronic switching spreads to other product families).  Many presentations 
and articles have been published on this thru the IEEE PSES/ISPCE symposium 
records and newsletters and are available thru the IEEE PSES.

Hopefully this rather long answer to your short question is 
helpful.

:>) br,  Pete

Peter E Perkins, PE
Principal Product Safety & Regulatory Affairs Consultant
PO Box 23427
Tigard, ORe  97281-3427

503/452-1201

Re: [PSES] Routine Test 60950-1, 62368-1

[John Allen]

Whilst generally not a mandated production test, a set of touch and ground 
conductor leakage currents might be a good idea when you have quite a few 
modules with different PSUs in the same rack/assembly, since you may well then 
exceed the maximum allowed for a unit with a single power cord with a 
non-locking power cord if that is what is used to connect to an adjacent supply 
outlet  – probably most relevant in the “fully loaded” configuration. You then 
require further precautions (locking plugs, labelling or even a permanent 
connection to the supply).

 

John E Allen 

W. London, UK

 

From: IBM Ken [mailto:ibm...@gmail.com] 
Sent: 03 September 2017 17:10
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Routine Test 60950-1, 62368-1

 

Hi Kurt!

At the system (end product level);

 

-Do you add a PDU and plug on the manufacturing line and plug all the modules 
into it?

-Do you have small screws, wires, etc which are used to assemble the end 
product which might fall into the product?

-Do you have any opportunity for miswiring/misplugging?

 

In most cases, it's a good idea to hipot the assembly as a complete product at 
the end of the manufacturing line.  It is not usually required to re-do each 
module hipot test separately, but rather just once at the Mains input (but I 
don't know the construction of your product). 

 

Regarding your comment about height above sea level;  the hipot test is based 
on the working voltage and the maximum operating altitude as designed (it is 
not dependent on the actual altitude of the factory).

 

-Ken A

 

 

On Sun, Sep 3, 2017 at 11:28 AM, Kurt Beneder  wrote:

Hi all,

i am defining the routine tests for a 19 inch Rack System according to IEC 
60950-1 and IEC 62368-1.
We test routinely the solid insulation of each submodule during production.
The final system is variable, so some modules are sometimes in the system or 
not, depending on the configuration from the customer.

The question for me is wether a routine test of the solid insulation of the 
final product is still necessary.
Especially if one has many circuits with hazardous voltages (relais contacts, 
power supply, other hazardous voltage outputs) which increases the test effort.

As far as i know the test voltages applied according the standards are for 
verification of solid insulation only.
This is done in our case at the subassembly level: every circuit against every 
other circuit of the submodule

So the argument sometimes that we have to retest the whole device for 
verification of the clearances, 

which could be compromised during assembly of the final product, is not valid 
for me 

as this would require much different and higher voltage levels dependent on the 
height above sea level of the test site.

What is your opinion?

Best regards

Kurt Beneder

-


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

All emc-pstc postings are archived and searchable on the web at: 
http://www.ieee-pses.org/emc-pstc.html

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:
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All emc-pstc 

Re: [PSES] Routine Test 60950-1, 62368-1

[IBM Ken]

Hi Kurt!
At the system (end product level);

-Do you add a PDU and plug on the manufacturing line and plug all the
modules into it?
-Do you have small screws, wires, etc which are used to assemble the end
product which might fall into the product?
-Do you have any opportunity for miswiring/misplugging?

In most cases, it's a good idea to hipot the assembly as a complete product
at the end of the manufacturing line.  It is not usually required to re-do
each module hipot test separately, but rather just once at the Mains input
(but I don't know the construction of your product).

Regarding your comment about height above sea level;  the hipot test is
based on the working voltage and the maximum operating altitude as designed
(it is not dependent on the actual altitude of the factory).

-Ken A


On Sun, Sep 3, 2017 at 11:28 AM, Kurt Beneder  wrote:

> Hi all,
>
> i am defining the routine tests for a 19 inch Rack System according to IEC
> 60950-1 and IEC 62368-1.
> We test routinely the solid insulation of each submodule during production.
> The final system is variable, so some modules are sometimes in the system
> or not, depending on the configuration from the customer.
>
> The question for me is wether a routine test of the solid insulation of
> the final product is still necessary.
> Especially if one has many circuits with hazardous voltages (relais
> contacts, power supply, other hazardous voltage outputs) which increases
> the test effort.
>
> As far as i know the test voltages applied according the standards are for
> verification of solid insulation only.
> This is done in our case at the subassembly level: every circuit against
> every other circuit of the submodule
> So the argument sometimes that we have to retest the whole device for
> verification of the clearances,
> which could be compromised during assembly of the final product, is not
> valid for me
> as this would require much different and higher voltage levels dependent
> on the height above sea level of the test site.
>
> What is your opinion?
>
> Best regards
>
> Kurt Beneder
> -
> 
>
> This message is from the IEEE Product Safety Engineering Society emc-pstc
> discussion list. To post a message to the list, send your e-mail to 
> emc-p...@ieee.org
>
> All emc-pstc postings are archived and searchable on the web at:
> http://www.ieee-pses.org/emc-pstc.html
>
> 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
>
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> Mike Cantwell mcantw...@ieee.org
>
> For policy questions, send mail to:
> Jim Bacher j.bac...@ieee.org
> David Heald dhe...@gmail.com
>

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Re: [PSES] Routine Test 60950-1, 62368-1

[John Woodgate]

If each rack-mounted product, and any power-distribution fitted in the rack 
itself, is routine-tested, I see no reason to test the rack as a whole, even 
for Europe. But you must document your decision and give reasons.
 
With best wishes DESIGN IT IN! OOO – Own Opinions Only
  www.jmwa.demon.co.uk J M Woodgate and 
Associates Rayleigh England
 
UK is a sovereignty, not a Zollverein-ty
 
From: Kurt Beneder [mailto:kurt.bene...@ieee.org] 
Sent: Sunday, September 3, 2017 4:29 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Routine Test 60950-1, 62368-1
 
Hi all,
i am defining the routine tests for a 19 inch Rack System according to IEC 
60950-1 and IEC 62368-1.
We test routinely the solid insulation of each submodule during production.
The final system is variable, so some modules are sometimes in the system or 
not, depending on the configuration from the customer.
The question for me is wether a routine test of the solid insulation of the 
final product is still necessary.
Especially if one has many circuits with hazardous voltages (relais contacts, 
power supply, other hazardous voltage outputs) which increases the test effort.
As far as i know the test voltages applied according the standards are for 
verification of solid insulation only.
This is done in our case at the subassembly level: every circuit against every 
other circuit of the submodule
So the argument sometimes that we have to retest the whole device for 
verification of the clearances, 
which could be compromised during assembly of the final product, is not valid 
for me 
as this would require much different and higher voltage levels dependent on the 
height above sea level of the test site.
What is your opinion?
Best regards
Kurt Beneder
-

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discussion list. To post a message to the list, send your e-mail to 
 >
All emc-pstc postings are archived and searchable on the web at: 
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 
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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  > 

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Re: [PSES] God EMC practice

[Jim Bacher]

What I have always set as a target is 6 dB better than spec on prototype /
first units tested, then 3 dB better on production audits.

That may no longer be good enough. The reason is a lot of products now have
radio receivers in them as in Bluetooth, wifi, NFC, and RFID. If your
unintentionally radiation is at the same frequency range as your receiver,
your radio performance will be degraded even if you are 6 dB down from the
limit.

Another thing to consider is that the rf noise floor is increasing. One
solution to help minimize the increasing floor is to lower the
unintentionally radiation requirements. So it could be in another 10 years
the limits might become 10 dB more strict.

Learn from the EMC experts, a number of which are on this list, and your
products will easily meet the margins I suggested.


Jim Bacher, JB Consulting
Product Regulatory Compliance Consultant
https://trc.guru/
IEEE Life Senior Member j.bac...@ieee.org

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[PSES] Routine Test 60950-1, 62368-1

[Kurt Beneder]

Hi all,

i am defining the routine tests for a 19 inch Rack System according to IEC
60950-1 and IEC 62368-1.
We test routinely the solid insulation of each submodule during production.
The final system is variable, so some modules are sometimes in the system
or not, depending on the configuration from the customer.

The question for me is wether a routine test of the solid insulation of the
final product is still necessary.
Especially if one has many circuits with hazardous voltages (relais
contacts, power supply, other hazardous voltage outputs) which increases
the test effort.

As far as i know the test voltages applied according the standards are for
verification of solid insulation only.
This is done in our case at the subassembly level: every circuit against
every other circuit of the submodule
So the argument sometimes that we have to retest the whole device for
verification of the clearances,
which could be compromised during assembly of the final product, is not
valid for me
as this would require much different and higher voltage levels dependent on
the height above sea level of the test site.

What is your opinion?

Best regards

Kurt Beneder

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[PSES] Test

[Edward Price]

Test of my new e...@jwjelp.com email address subscription.

Ed Price
WB6WSN
Chula Vista, CA USA





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