Dear Friends,
Thanks very much to the input regarding CB Tripping During Fault Testing.
There were many thoughts on the subject and I am sure that next time the wall
CB trips during fault tests at your third part certification laboratory, you
have something to talk about - make sure they do not
Hi Peter:
My comments were based on the proposed requirement to
test the PE path with the circuit prospective current
transient, e.g. 200 amps from a 10,000-amp source for
the period of time required to operate the overcurrent
device -- say less than a second or so.
(The 200 amps is a
This thread has been largely theoretical. Let's look at
some empirical test results for a product I just completed
testing.
The product has a redundant power configuration and nearly
identical current paths for each of two power supplies,
though one has about 2 in. longer traces on one side of
From: Rich Nute
Sent: Wednesday, February 05, 2003 12:20 PM
Hi Peter:
Hi, Rich.
This test implies a near 0-ohm fault to the
PE, where the PE circuit includes a PE trace
on the PWB.
That's a reasonable assumption and is convenient for the
purposes of testing. It is unlikely to be the
Hi Peter:
Not quite. I^2·t will tell you the let through current of
the copper trace, but will not necessarily tell you if the
construction will be compliant. The compliance criteria for
this test include:
* no damage to the trace (no lifting, probably no
Hi Chris:
It seems funny to me that most equipment has been historically made with
18AWG protective ground pigtail wires; and 25A ground fault tests have been
used for years.
Now that PC traces are being used for protective ground; we want to test
with 200A or greater impulse
. Tarver; emc-p...@majordomo.ieee.org
Subject: Re: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)
Why not provide a fuse to prevent deterioration of the PE trace on a PCB?
Joking of course, but now that I have your attention, I would like to see
]
Sent: Tuesday, February 04, 2003 11:36 AM
To: Peter L. Tarver; emc-p...@majordomo.ieee.org
Subject: Re: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)
Why not provide a fuse to prevent deterioration of the PE trace on a PCB?
Joking of course
Chris,
Douglas Brooks wrote an article about Preese's and Onderdonk's equations
for fusing currents of wires, which was published in Printed Circuit
Magazine. It can be downloaded from UltraCAD's web site at
http://www.ultracad.com/fusing.pdf
Appendix F of the book that I am writing for
I read in !emc-pstc that Chris Maxwell chris.maxw...@nettest.com wrote
(in 83d652574e7af740873674f9fc12dbaaf7e...@utexh1w2.gnnettest.com)
about 'EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)' on Tue, 4 Feb 2003:
This would make heat dissipation different
(was Re: Circuit Breaker
Tripping Dring Fault Tests)
Not quite. I^2·t will tell you the let through current of
the copper trace, but will not necessarily tell you if the
construction will be compliant. The compliance criteria for
this test include:
* no damage to the trace (no lifting
Not quite. I^2·t will tell you the let through current of
the copper trace, but will not necessarily tell you if the
construction will be compliant. The compliance criteria for
this test include:
* no damage to the trace (no lifting, probably no
discoloration)
* no damage to
Message-
From: drcuthbert [SMTP:drcuthb...@micron.com]
Sent: Monday, February 03, 2003 7:50 PM
To: 'John Woodgate'; emc-p...@majordomo.ieee.org
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)
What is needed is the I squared t
I've had extensive discussion with UL regarding the
performance of this test. Below are my comments, taken from
these discussions.
-Original Message-
From: Carl Newton
Sent: Monday, February 03, 2003 9:20 AM
1. Three samples are tested;
Intended to demonstrate repeatability of
To: emc-p...@majordomo.ieee.org
Sent: Monday, February 03, 2003 11:19 AM
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)
A slight divergence from the EN specifically, but I thought that the
following would be helpful to this thread:
I am
, February 03, 2003 11:19 AM
Subject: RE: EN60950 protective conductor test (was Re: Circuit Breaker
Tripping Dring Fault Tests)
A slight divergence from the EN specifically, but I thought that the
following would be helpful to this thread:
I am presently working this issue with a UL engineer
This thread has been interesting. I am, at this moment, considering a design
where I am almost forced to use a PC (printed circuit) trace for Earth ground.
It seems funny to me that most equipment has been historically made with 18AWG
protective ground pigtail wires; and 25A ground fault tests
I read in !emc-pstc that Nick Williams nick.willi...@conformance.co.uk
wrote (in p05200f03ba60957364e4@[192.168.1.28]) about 'EN60950
protective conductor test (was Re: Circuit Breaker Tripping Dring Fault
Tests)' on Fri, 31 Jan 2003:
At 12:22 + 31/1/03, John Woodgate wrote
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