That's what I love about this mailing list. I learn something new most every
day. Thanks Tania!
----------
From: Grant, Tania (Tania) [SMTP:[email protected]]
Sent: Wednesday, March 10, 1999 4:27 PM
To: 'EMC-PSTC - forum'; 'WOODS, RICHARD'
Subject: RE: Rack System Safety (UL1950/EN 60950) Questions
Richard,
Regarding your last statement "....I don't believe that they [CSA
& UL]
will accept each others marks."
Certain UL and CSA component standards have been "harmonized" and, I
believe, this effort is continuing. If you look at Appendix P.2
[be sure
it is P.2 and not P.1] of UL 1950, 3rd edition, you will find a
matrix of
UL and CSA component standards where meeting one or the other is
considered
acceptable for meeting the requirements of UL1950, 3rd edition.
Additionally, if you are working with an astute UL engineer, very
often they
will inform you of additional components that fall under that
category but
have not yet been published in this Appendix.
Tania Grant, Lucent Technologies, Octel Messaging Division
[email protected]
----------
From: WOODS, RICHARD[SMTP:[email protected]]
Sent: Wednesday, March 10, 1999 5:00 AM
To: 'EMC-PSTC - forum'
Subject: RE: Rack System Safety (UL1950/EN 60950) Questions
As I think about this situation, there is a way of obtaining UL
Listing on
the rack and have other certification marks on the internal
equipment. Have
UL List just the rack without the equipment. Now you can mix and
match the
internal certified equipment as you see fit keeping in mind not to
exceed
the cooling and electrical capacity of the rack. This is what we use
to do a
decade ago at a mini-computer company. We would configure systems
from
Listed racks, cpus, disks, tapes, etc.
Now to Jim's point. There is no law that requires one agency to
accept the
certification marks of another agency. For example, UL will not
accept ETL
marks on components and both are NRTLS. The only way one agency will
accept
the marks of another is if there is an agreement between them. The
CB scheme
is one good example. CSA and UL have an agreement to accept each
others test
data I believe, but I don't believe that they will accept each
others marks.
----------
From: Jim Eichner [SMTP:[email protected]]
Sent: Tuesday, March 09, 1999 3:23 PM
To: 'EMC-PSTC - forum'
Subject: RE: Rack System Safety (UL1950/EN 60950) Questions
Re Richard's item 5)...
> 5. UL requires that all internal equipment be UL Listed
or
> Recognized.
>
If that is true, then the value of the CSA/NRTL mark, and
conversely
the
cUL mark if CSA plays this way too, is highly questionable.
Do you
have
a direct-from-UL interpretation saying that they are not
accepting
the
CSA/NRTL mark? If so, I would expect CSA to take action to
defend
its
mark, and UL to have no firm ground to stand on!
Comments?
Jim Eichner
Statpower Technologies Corporation
[email protected]
http://www.statpower.com
Any opinions expressed are those of my invisible friend, who
really
exists. Honest.
> -----Original Message-----
> From: WOODS, RICHARD [SMTP:[email protected]]
> Sent: Tuesday, March 09, 1999 11:15 AM
> To: [email protected]; [email protected]
> Subject: RE: Rack System Safety (UL1950/EN 60950)
Questions
>
> 1. Peter, equipment with the standard NEMA plug is
considered
to be
> Class A..
> 2. Equipment using the heavy duty Industrial plugs
complying
with
> IEC
> are considered to be Class B. I have never seen those used
inside
rack
> mounted equipment.
> 3. If the power supply is UL "Listed", then temperature
> measurements
> are not required. However, most power supplies are
categorized as
> "Recognized" and are therefore incomplete in construction
- that
is,
> they
> cannot pass the safety requirements for a stand alone
power
supply.
> Temperature measurements will be required.
> 4. Stability is performed in a worst case situation,
but reason
is
> also
> taken into account. Most likely, you will determine that
it is
> possible and
> reasonable to assume that more than one assembly can be
extending
at
> the
> same time.
> 5. UL requires that all internal equipment be UL Listed
or
> Recognized.
>
> ---
> From: [email protected] [SMTP:[email protected]]
> Sent: Tuesday, March 09, 1999 11:26 AM
> To: [email protected]; [email protected]
> Subject: Rack System Safety (UL1950/EN 60950)
Questions
>
> Dear All,
>
> I would like to know some of your professional
advice on
some
> issues reagrding rack systems to be evaluated to
UL1950/EN
60
> 950.
>
> 1. For the North America, does a NEMA 125 V, 20 A
plug meet
the
> pluggable B definition?
>
> 2. What are some plug configurations which will meet
the
> pluggable B equipment requirements for North America
and
> Europe?
>
> 3. Does anyone have experience with UL and/or CSA
and/or
TUV
> when testing a unit employing a
Recognized/Certified/Approved
> computer type "totally enclosed" power supply? I am
interested
> to
> know if temperatures should be monitored within such
a power
> supply. So far, I have been asked to thermocouple
various
points
>
> within the power supply and as you all know, it
could get
very
> crowded in there. I am interested to know if someone
out
there
> knows if such a waiver exists for totally enclosed
Approved
> power
> supplies.
>
> 4. When conducting stability tests for rack systems,
should
all
> the
> serviceable card cages be extended out or is it
enough to do
it
> one
> at a time.
>
> 5. For a CSA NRTLC unit employed in the rack system,
does
> anyone know if the CSA NRTLC Mark is automatically
accepted
by
> UL or does UL require that the unit must be
re-investigated
and
> placed under their Follow-Up Program?
>
> 6. Has the US Robotics Listed "Sporster" card modem
been
> evaluated to UL1950 Third Edition?
>
> 7. Can I List/Certify a rack system to UL1950 Third
Edition
if
> the
> units within it have been Listed/Certified to UL1950
First
> and/or
> Second Editions? I do not think so, but am
interested to
hear
> your
> opinions.
>
> 8. How is a CB test report done for a rack system
which
consists
>
> of previously Listed/Certified/Approved units? Does
the CB
> scheme
> Recognize the Approvals of the various test agencies
> (UL/CSA/TUV)?
>
> Thanks in advance.
>
>
> PETER S. MERGUERIAN
> MANAGING DIRECTOR
> PRODUCT TESTING DIVISION
> I.T.L. (PRODUCT TESTING) LTD.
> HACHAROSHET 26, P.O.B. 211
> OR YEHUDA 60251, ISRAEL
>
> TEL: 972-3-5339022
> FAX: 972-3-5339019
> E-MAIL: [email protected]
> Visit our Website: http://www.itl.co.il
>
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