Hi Chris,
As usual, Rich is correct that removing more then one ground connection
would be an improper single fault test.
However, Rich's comment...
A single-fault test is with one ground open (a meaningless
test when there is a second ground in place)...
Is not quite accurate, the test is
Hi Chris:
Consider a product with two, independent protective
grounding/earthing connections. This may be by
means of two power cords (as is done for uptime
reliablity by employing parallel power supplies) or
by means of one power cord and a separate ground
connection (as, for example, by
All,
Paragraph C4 in cfr 1020.40 States: Each door of a cabinet X-Ray
system shall have a minimum of two safety interlocks.
One, but not both of the required interlocks shall be such that the door
opening results in physical disconnection of the energy supply circuit to
the high
Hmm,
This question centers around whether two separate ground cables equals
double protection.
Safety standards call for single fault testing. For Class I equipment, one
of the single fault test conditions is removal of the ground connection.
I'm curious how most test labs would
Hi Dave:
Can anybody tell me where it is defined at what point in production it is
permissible to apply the UL mark? Can it only be done after the hi-pot has
passed? Or is it OK to have the label applied before the test as long as the
units are clearly marked as having failed
Forwarded for Mike Hopkins.
Original Message
Subject: RE: ESD Question
List-Post: emc-pstc@listserv.ieee.org
Date: Wed, 30 May 2001 16:06:48 -0400
From: Mike Hopkins mhopk...@thermokeytek.com
To: 'Chris Maxwell' chris.maxw...@nettest.com,'Sandy
Mazzola'mazzo...@symbol.com,
I've also seen this effect when testing component power supplies
(off-line switch-mode converters, 50-500W).
The problem became apparent when a customer added another EMI
filter ahead of our power supply, creating a system we didn't
anticipate. The power supply alone passed the test, but the
I would have to state that the polymeric material would be listed under the
manufacture of that material (not necessarily the EMI gasket manufacturer)
and the shield effectiveness data would be from the manufacturer of the EMI
gasket. You should be able to contact the EMI gasket manufacture for
Hi Peter,
Gaket material are covered as Recognized Plastics material. They are in the
yellow books, just like regular plastics material (QMFZ2). Some gasket
material were Recognized under that QMFZ2 category, but there is also a special
category (Q) that covers gaskets in particular. I
Dear All,
While UL does its' own research, under what UL category one can find
polymeric insulated RFI/EMI gaskets that have been previously evaluated for
flammability and shielding effectiveness?
PETER S. MERGUERIAN
Technical Director
I.T.L. (Product Testing) Ltd.
26 Hacharoshet St., POB
Forwarded for Leslie Wood. Please CC Leslie (lesliew...@aol.com) on
replies.
Dave Heald
Original Message
Subject: JISC to U.S. Code equivalency
List-Post: emc-pstc@listserv.ieee.org
Date: Thu, 31 May 2001 20:49:00 EDT
From: lesliew...@aol.com
To: emc-p...@majordomo.ieee.org
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