Failed on the first try. Let's try again.
Peter
-Original Message-
From: Peter Tarver [mailto:peter.tar...@sanmina.com]
Sent: Friday, December 14, 2001 8:57 AM
To: 'EMC-PSTC Forum'
Cc: 'Barry Esmore'
Subject: RE: 2 Phases in North America
This is a recurring topic.
While
Rich -
While I can't speak for Chris, there are a few reasons to
perform production line ESTs on 48V dc mains powered
equipment.
1) in 48Vdc SMPSs, the voltages present on transformer
insulation are typically in excess of ELV limits. If the
power supply has had fault testing performed that
Dave -
Perhaps I was misinformed, but it was my understanding that
70V battery was not panEuropean, but is specific to Germany
and Austria, and then not necessarily ubiquitous in those
countries.
I'd appreciate your expanding on this.
Regards,
Peter L. Tarver, PE
Product Safety Manager
We are looking for a good failure analysis company in the SF
Bay area. Anyone have any leads for companies you've had a
positive experience with?
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
peter.tar...@sanmina.com
Perry -
A note of general concurrence with Joe's take on your
circuits. The various DSL power feeds are at this time
treated as hazardous voltage circuits. There is activity in
IEC, TC47, to consider requirements for remote feeding
circuits, but publication is not imminent.
The UL/CSA
Good morning.
I have a Yokogawa Electric, Model 2509, digital wattmeter
for which I have no manual. I searched both Manuals Plus'
and Manual Merchant's web sites and came up negative.
Even though this is a very simple meter, I would like to
have a manual for each piece of equipment in my
Rich -
Regarding UL Recognized Component Appliance Wiring Material,
the yellow book states that the marking must be on a tag,
the reel or smallest unit container, not surface marked on
the wire insulation, as referred to by Greg. Very few UL
FUS folks will accept surface marking, though I had
Gary -
Or for the less scrupulous than careless, to remove the
certification mark from a product and place it one that is
not safety certified.
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
peter.tar...@sanmina.com
From: Gary McInturff
The Product
Peter -
If you have such a memo, please do provide a copy. I my
years working at UL and working with them since, it was ever
abundantly and adamantly maintained (by UL's FUS Label
Services group) that the Control Number is a required part
of the Listing Mark and there is no substitution for it.
Rich is quite right, in general. There are UL Listing Marks
available, but they won't have the other three required
elements that make up the complete marking (some may include
the word Listed).
The page Rich referred to in a UL Follow-Up Services
Procedure, though, is separate from the Section
Sorry. I clicked too fast during spell checking. I meant,
thank you.
-Original Message-
From: Peter Tarver
Think you, Angus.
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
Visit
Think you, Angus. The title for this standard is:
Primary Batteries - Part 4: Safety Standard for Lithium
Batteries
In my case, and I think this is true of all Li ion cells and
batteries, it is a secondary battery, meaning rechargeable.
Primary batteries can't be or aren't intended to be
: Peter Tarver
I am looking for safety standards related to large
lithium-ion secondary batteries (nonautomotive). I've
searched several standards web sites (IEC, ANSI, IEEE,
CENELEC, BSI, UL, CSA) and there appears to be nothing
specific to lithium-ion cells.
Your help will be appreciated
I am looking for safety standards related to large
lithium-ion secondary batteries (nonautomotive). I've
searched several standards web sites (IEC, ANSI, IEEE,
CENELEC, BSI, UL, CSA) and there appears to be nothing
specific to lithium-ion cells.
Your help will be appreciated.
Regards,
Peter
the ACA on the topic of
when AS60950 will replace AS3260.
So my question stands.
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
peter.tar...@sanmina.com
-Original Message-
From: Peter Tarver
Sent: Wednesday, October 10, 2001 2:27 PM
Does any one have
Does any one have a view of when (or if) AS/NZS 60950 (based
on IEC60950, Third Edition) will become the legally required
standard for ITE in Australia and/or New Zealand (whether
independently or through TS001)?
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
.
Peter
-Original Message-
From: John Woodgate
Sent: Wednesday, October 03, 2001 10:45 AM
I read in !emc-pstc that Peter Tarver
peter.tar...@sanmina.com wrote
some stuff
Yes, there can be confusion about these terms.
However, I suspect that
the TC28 'material category' takes
John -
The RTI you are referencing from IEC TC28 appears to be not
the same parameter as being discussed. In UL parlance, as
you surmised, RTI represents Relative Temperature Index
and gives a maximum operating temperature at which a
polymeric material may experience for its other properties
to
Tony -
The UL746 series of standards are referenced in CSA/UL60950,
Annex P.2. RTI is a material property evaluated in UL746B,
Polymeric Materials - Long Term Property Evaluations. IIRC,
guidance on the applicability of RTI is given in UL746C,
Polymeric Materials - Use in Electrical Equipment
Yes.
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
peter.tar...@sanmina.com
-Original Message-
From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On
Behalf Of Stone, Richard A
(Richard)
Group,
can you
The infamous Laser notice 50.
The following is Excerpted from Federal Register / Vol. 66,
No. 144 / Thursday, July 26, 2001 / Notices under the
heading titled, Laser ProductsConformance with IEC
608251, Am. 2 and IEC 60601222 (Laser Notice 50).
CDRH intends to amend its standards for laser
The tardiness of this reply is due to my employer's
insistence upon performance of tasks of their choosing to
accommodate remuneration in the locally common monetary
exchange units.
Jim Eichner pointed out a fallacy in my below statement and
I must acquiesce. By operating from memory (but I
Ed -
First and foremost, there must exist a resonant cavity
formed inside the semiconductor or in combination of the
semiconductor die and its packaging. Then the threshold
current (for population inversion of the lasing medium) must
be exceeded. Only the latter is related to external faults
I don't have the answer to Glenn's question, but do have a
comment on Nick's response.
Nick states: The rating of a UL rated fuse is more or less
the current at which it blows. The rating of a fuse to IEC
127 (used throughout Europe) is more or less the working
current of the fuse and the
Not so. Most household appliances contain motors (excluding
entertainment appliances). Motors (ac induction types; the
most commonly used) are generally less efficient at lower
voltages (largely by virtue of their increased I^2*R loss)
and draw more current to perform the same amount of work or
Peter -
1) Agreed. Keep in mind that IEEE 802.3 compliant signals
are unearthed SELV and how SELV is derived in the power
source was not specified.
2) There are potential problems, but this is not to say
insurmountable. I doubt, however, that LAN cable meeting
Reinforced insulation
Amund -
For the most part, installation code issues, component
standard issues, power cross (overvoltage) testing and a
number of other items sprinkled throughout the standard.
You will need to buy a copy of the standard to get the full
picture. It is not simple enough to place in an e-mail.
I have a Kurz, model 441s hot wire probe unit. Refer to
http://www.kurz-instruments.com/
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
peter.tar...@sanmina.com
-Original Message-
From: Kurt Mikolajewski [mailto:kmiko...@catena.com]
Sent: Monday,
Job Title: Product Integrity Engineer
Job Location: San Jose, CA
Company Description:Sanmina is a Tier-1 electronics manufacturing
services (EMS) company with over 50 world class manufacturing facilities.
Sanmina provides a full spectrum of integrated, value-added services that
Job Title: Product Safety Engineer
Job Location: San Jose, CA
Company Description:Sanmina is a Tier-1 electronics manufacturing
services (EMS) company with over 50 world class manufacturing facilities.
Sanmina provides a full spectrum of integrated, value-added services that
includes:
The same is easily said of other products, Rick, like firearms (where there
are politically motivated lawsuits in progress and also directly analogous
to the tobacco lawsuits on many levels), hot coffee from MacDonalds, ad
infinitum. That a product is known to be hazardous or dangerous is not
From the Telecom Digest
Monty Solomon wrote:
Cell Phone Suit Will Get Its Day in Court
NEW ORLEANS, La. - In ruling that could shake the cell phone industry, a
federal judge let stand a lawsuit that says companies are making and selling
cell phones with the knowledge that they may be
The component is marked, does not comply...?
I haven't seen that one yet.
Regards,
Peter L. Tarver, PE
Product Safety Manager
Sanmina Homologation Services
peter.tar...@sanmina.com
-Original Message-
From: acar...@uk.xyratex.com [mailto:acar...@uk.xyratex.com]
Sent: Wednesday,
Hi, KB.
It is incorrect that IEC825 does not apply to components. In the case of
components, the worst case emissions, based on power supply and any other
factors that affect output power/energy must be considered.
The FDA requirements in 21CFR requires all laser sources, devices or
products to
I need to add the following to clarify my below statements regarding FDA
certification.
21CFR, Chapter I, Section 1002.1(b) allows exemption for components intended
for sale exclusively to other manufacturers for use in other products. The
implication is that, if the component might be sold
...@mail.monarch.com'; peter.tar...@sanmina.com;
Peter Tarver, in the message below, mentions he obtained a
new edition of
the IT safety standard CSA60950/UL60950.
I have been unable to locate a Dec. 1, 2000 edition of
UL60950 on the IHS
Global DOcument website, nor have I found a CSA60950
Early this week I received a copy of CSA60950/UL60950, Third Edition, the
new Bi-National Standard, based on IEC60950, Third Edition. The edition
number was maintained to correspond with the IEC standard edition number.
Publication date is 1DEC2000. Nifty.
Regards,
Peter L. Tarver, PE
At one time or another, we certainly all do. Each NRTL has its own level of
absurdity, whether by being too harsh or too lax.
There is one NRTL the international safety community of a previous employer
had agreed was lax to the point of not accepting any component or OEM device
that certified
I've had this kind of thing pulled on me before, to. Start with their team
leader, then group leader , then section head, then dept. manager, until you
get satisfaction.
Peter Tarver
ptar...@nortelnetworks.com
-Original Message-
From: Doug [mailto:dmck...@gte.net]
Sent: Thursday
Gary -
The below may be a little more than you bargained for, but here goes. My
apologies, if this is more basic than your question.
Each of the drawings in Figures NAB.1 and NAB.2 show grounding electrodes at
the bottom. In Figure NAB.1, the electrode is used to earth the centralized
dc power
Kurt -
Except under special circumstances, the USNEC does not use color coding for
phase conductors. There are reserved insulation colors for ground (green,
with one or more yellow stripes) and for neutral (white or natural gray
[whatever that is]). Otherwise, your free to use whatever color
Richard -
Then the answer is no. The MOT, as Pete Perkins pointed out, establishes
the test points for thermal conditioning, but solder resists are then tested
in conjunction with the PWB only for flammability classification.
Regards,
Peter L. Tarver, PE
ptar...@nortelnetworks.com
You're welcome, Richard.
MOTs are developed for a copper clad industrial laminate and verified by
certain tests on a finished PWB. Conformal coatings are not a normal part
of this process, though I suppose a board house could ask for such
considerations to be made for a selection of coatings.
Richard -
Basically, yes, though you may want to throw in a fudge factor to assuage
your caution/due diligence monkey.
FYI: The Maximum Operating Temperature (this is a normal operating condition
temperature) for a PWB is based on accelerated aging testing, and comparing
as received performance
Richard -
What is required is approval by any of the individual state's governmental
bodies in Australia. I can't find my list of authorities at the moment, but
perhaps someone else can.
Regards,
Peter L. Tarver, PE
ptar...@nortelnetworks.com
-Original Message-
From:
Chris Maxwell asks: Can anybody shoot a hole in this theory with a single
fault condition?
This subject has been debated before, on this list and elsewhere.
Safety is always relative. In the scenarios you painted, Chris, the phase
conductor always has an intact fuse after the neutral fuse
There seems to be some confusion regarding terminology and the location of
the overcurrent protective devices being discussed.
In the US and Canada, if a circuit breaker is located in the panelboard,
John is generally correct that the neutral will not be controlled by the
circuit breaker. On the
There is no correlation between air filter flammability class and the UL94
classifications.
Regards,
Peter L. Tarver, PE
ptar...@nortelnetworks.com
-Original Message-
From: Jim Eichner [mailto:jim.eich...@xantrex.com]
Sent: Friday, October 06, 2000 10:17 PM
To: 'emc-p...@ieee.org'
Bimetal switches have been used for decades and proven generally to provide
an adequate or better safety protection function. Not all bimetal switches
are autoreset types; some require manual resetting. I've also experience
bimetallic thermal protectors in motors in an open failure mode, more
Tamura makes a good quality product, but most of their transformers are UL
Recognized, rather than Listed.
You can search UL's web site in their Certifications area, using the CCN
XOKV and probably get the latest set of companies with Listings.
Regards,
Peter L. Tarver, PE
Luiz -
Bimetal switched are used as manual and automatic reset thermal protectors
in electric motors, transformers. Very common and has been for many years.
Regards,
Peter L. Tarver, PE
ptar...@nortelnetworks.com
-Original Message-
From: jim_bac...@mail.monarch.com
Rich and Andy -
There is an additional reference in 4.3.9 of IEC60950, Second Edition, and
applies where certain types of required insulation can be bridged, rather
than being limited to just power supply cord conductors (though this could
easily have been the origin of the requirement [actually,
Ted -
At issue, really, is whether or not the under side of the raised floor is
used for environmental air, not simply that it's in a computer room. For
the question at hand, though, I'll assume that's the case.
My first inclination is to say it's not allowed. If you also look at 300-22
of the
Lisa -
While I can't speak directly to the case in EN61326, this sounds a lot like
the concept of a centralized dc power system, as addressed in UL1459 and
carried over into CSA950/UL1950 and working it's way into IEC60950 as a dc
mains supply (there is only reference in IEC60950, Third Edition,
Lauren -
I'm not familiar with NFPA79, so I'll answer only with regard to NFPA70 (the
US NEC).
The 125% issue in the NEC is for two items: attachment plugs sizing and
circuit breaker sizing (1/1.25 = 0.80), both relative to load current.
Attachment plugs for equipment that contain motors must
My experience with safety agencies is they do not want to rely on traces
opening to act as fuses and no standards have been developed, that I am
aware of, to address this issue. Fuses certification gets involved in the
metallic alloys used, to the fraction of a percent, the conductor size,
but to rely on that mechanism
for fire prevention is a bit far fetched. From my limite experience with
fuses, there is generally a large structure that is enclosed in sand to
prevent a fire from spreading.
Jim Freeman
Peter Tarver wrote:
My experience with safety agencies is they do not want
Richard is absolutely correct. It's like trying to compare a match stick to
a bon fire.
Regards,
Peter L. Tarver, PE
ptar...@nortelnetworks.com
-Original Message-
From: wo...@sensormatic.com
I just went through this myself. There is no real correlation between UL94
flame ratings and
Bandele -
Please forgive an ignorant question:
I'm not going to pretend to be an EMC standards expert, but I fail to see
how the presence or absence of processing an incoming signal has anything to
do with whether there is a direct or indirect connection to outside lines.
To wit: outside is
Further on HD topics, I reviewed several HDs on the IHS web site and found
them to not be of much use, beyond giving standard references in each
country for the point of harmonization, with dates of withdrawal, and the
like. I didn't find any, in the dozen or so I looked at, covering diverse
Richard -
I have no direct evidence to support a claim either way, but if a material
can only meet HB requirements, I have strong doubts about its ability to
have a FS of 200, using ASTME84 test. The Steiner Tunnel testing uses a
significantly different method from the 1/2 in. flame test used
Other items include:
service entrance equipment
panelboards and circuit breakers (in general)
insulated wiring
GFCI outlets
flue dampers
double-walled flue pipes
Regards,
Peter L. Tarver, PE
ptar...@nortelnetworks.com
-Original Message-
From: Price, Ed
Sent: Monday, July 31, 2000
Peter -
Thermistors are in common usage and my limited experience with them
indicates they are reliable for their intended function.
The thermal issues have been discussed, and the usual regimen for high
temperature components applies. I'm not aware of any other particular
safety concerns.
I really don't have a clear idea of whether or not your solution will work.
Let us know.
NTCs, as with most thermistors, get very hot when in their switched state.
For the NTC, that's it's steady-state condition. I wouldn't put this in a
junction box with other wiring, unless you're absolutely
That's really just a rule of thumb. A working premise that provides
reasonable results in a relatively short time. As Kaz mentioned, it's not
uncommon for some circuits/parts to exhibit a cycling of temperature, either
by cyclical loads presented to them or some form of (generic) limiting
Peter -
UL has no problem with components bridging the insulation, provided you
comply with the appropriate testing in the standard and provide otherwise
appropriate clearances and creepages (just as you expected).
In Europe, the Nordic countries require Supplementary insulation between
SELV and
Not so dumb. It's probably a translation issue, since Kenji and the English
alphabet are nothing alike. I've mostly seen it spelled in all-caps as
DENTORI.
Regards,
Peter L. Tarver, PE
Homologation Engineering
Nortel Networks
ptar...@nortelnetworks.com
-Original Message-
From:
For ITE, refer to IEC60950, 3rd ed, Subclause 1.7.7.2, first dashed
paragraph.
Regards,
Peter L. Tarver, PE
Homologation Engineering
Nortel Networks
ptar...@nortelnetworks.com
-Original Message-
From: bur...@andovercontrols.com [mailto:bur...@andovercontrols.com]
Sent: Wednesday, June
Don -
There are additional details beyond the following, but in essence, there are
pull-out and wire retention tests that are done for field wiring purposes
that may or may not have been done for factory wiring purposes. Field
wiring terminal blocks are subjected to the full range of tests
Hi, Peter.
From: Peter Merguerian [mailto:pmerguer...@itl.co.il]
Dear All,
1. For ITE (without a connection to a telecommunication
network), what are the applicable standards and requirements? I assume
AS3260
(safety) and AS3548 (emc) and the manufacturer applies the C-Tick Mark (ie
Hi Rich.
The exception being Table G.2 of IEC60950, 3rd ed. Table G.2 clearly states
its applicability up to 2km, when using Annex G and its Alternative method
for determining minimum clearances.
Peter L. Tarver, PE
ptar...@nortelnetworks.com
From: Rich Nute [mailto:ri...@sdd.hp.com]
Hi
My apologies for not sending this to the group originally. Others may have
interest.
Regards,
Peter L. Tarver, PE
Homologation Engineering
Nortel Networks
ptar...@nortelnetworks.com
-Original Message-
From: Tarver, Peter [SC1:4N02:EXCH]
Sent: Thursday, May 25, 2000 1:16 PM
To:
IEC60825-1 contains requirements for noncoherent infrared radiation.
Likewise does EN60825-1, with Amendment A11.
Regards,
Peter L. Tarver, PE
ptar...@nortelnetworks.com
From: Israel Yeshurun [mailto:israel_yeshu...@creoscitex.com]
Can some comment on this ?
Can Infrared
From: Ned Devine [mailto:ndev...@entela.com]
Hi,
Hi, Ned.
OK, I wasn't going to say anything, but.
1.A UL Listed product complies with all of the applicable
requirements. Usually from a standard.
2.A UL Recognized Component does not comply with all of
the applicable
All -
In addition to all of the other comments (all essentially true), I would
like to clarify one issue, touched on by Rich Nute, but not made as clear as
could be. The backwards UR ligature is copyrighted by UL and can not be
applied to a product certified by another NRTL, without violating
Jim -
Most any calibratable voltmeter with 1000+ Ohms/V should work OK. The
Ohms/V information should be on the indicator plate. Is there a specific
test you're concerned about using this meter for, or is it for general
applications?
For the manual, try posting to sci.electronics.equipment and
Peter -
These are all in the CEC and US NEC. You need to purchase one or both
(they're significantly similar on all of your points in question).
Regards,
Peter L. Tarver, PE
Homologation Engineering
Nortel Networks
ptar...@nortelnetworks.com
-Original Message-
From:
Arjen -
Check the Conditions of Acceptability on the coatings you're interested in
using. UL Recognized conformal coatings are, for the most part, are tested
for use on the bare board (base laminate) and are not tested for use on
solder masks.
Regards,
Peter L. Tarver
Nortel Networks
Happy holidays, to one and all.
I am looking for a contact for product safety certifications at National
Semiconductor. The operators at their Santa Clara facility are useless,
unless you have a name.
Regards,
Peter L. Tarver, PE
Nortel Networks
ptar...@nortelnetworks.com
-
This
The key word below is allow. There is no requirement that one NCB accept
the report of another NCB. I am aware of one case where a CB Scheme Test
Report from one NCB was refused out of hand by another NCB in the same
country (both shall remain nameless), without any rational qualification.
I
Better yet, how about the subscribers taking the additional two or three
seconds it takes to do the responsible thing and delete it themselves?
Peter L. Tarver
Nortel
ptar...@nt.com
-Original Message-
From: Robert Macy [SMTP:m...@california.com]
Sent: Thursday, October 08, 1998 12:05
_
Subject: RE: US NRTL required ?
Author: Peter Tarver peter.tarver.ptar...@nt.com at INTERNET
Date:9/22/98 11:17 AM
Require? No. Will they? Yes, under certain circumstances and certain
product categories, like ITE. Laptops for instance
Richard -
For a long time, UL (and I believe CSA) thought any device deriving power
from a Class 2 source needed listing. In fact, they were adamantly opposed
to it, even when requests for such certification were made. UL's primary
basis was that the NEC didn't care what was supplied by a Class
To muddy the waters further, Ron, I offer a converse reminder: many
Authorities Having Jurisdiction are still using versions of the NEC the
precede the introduction of 800-4 (and the previous location of the same
idea in the 1990 NEC that eludes me). I've known of some jurisdictions to
use the
Even though it wasn't you point, Daniel, it should be noted that the CB
Scheme provides for participating NCBs to accept one anothers' test data,
but by no means guarantees that an NCB reviewing a CB Scheme Test Report
will not ask to perform some testing. The testing might be required by an
NCB
right now, according to their latest literature.
Jim
__ Reply Separator
_
Subject: RE: EN 60950 A5
Author: Peter Tarver peter.tarver.ptar...@nt.com at Internet
Date:08/28/1998 1:51 PM
Jim
Just to fill the pot with more speculation, my recollection of college
chemistry tells me that alcohol readily absorbs moisture from the
atmosphere, so that any container opened to normal atmospheric conditions
for more than a few seconds will autodilute to somewhere around 93% (that's
the number
Jim -
Yes, that's pretty much how respooling works.
The most odd aspect was that this was wiring already in a wiring harness,
taken from a box with the appropriate wiring harness labeling. The FUS Rep
wanted to see our drawings to verify the design of the harness, which is
normal, but
In the following, I'll speak only to UL certified wire. To get an official
reading, call the nearest UL office and ask for the client advisor, then ask
them to direct you to an engineer working with wire and cable.
One of the best resources for information about any UL product category is
the
A few safety type markings are translated into French in Annex NAA of
CSA950/UL1950.
Regards,
Peter L. Tarver
Nortel
ptar...@nt.com
--
From: ron_pick...@hypercom.com[SMTP:ron_pick...@hypercom.com]
Sent: Tuesday, June 23, 1998 3:06 PM
Hello from quite sunny
A point of clarification here. UL Recognized AWM isn't required to be
surface marked at all. The marking is perfectly legitimate if it is on the
spool the wire is taken from.
Yet another voice chiming in that it was probably not traceable as being R/C
AWM.
Regards,
Peter L. Tarver
Nortel
Gary -
You seem to be doing just fine for your current market. As you market
expands (you mentioned GOST), however, the CB Scheme Test Report does offer
portability to a greater degree than a lesser. Many of the agencies will
want a sample for a looksee, a few may want to perform minor
Richard -
In addition to the previously mentioned manufacturers, there is also Behlman
http://www.behlman.com/
also sold through Electro Venture
http://www.electroventure.com/
Regards,
Peter L. Tarver
Nortel
ptar...@nt.com
--
From: Richard
Alan -
I'm not certain about the origin of the application of Tables 3, 4 and 5 in
your example, but since Tables 3, 4 and 5 generally have lesser distances
for the same voltages than are found in Table 6, this seems primarily an
academic exercise for which I'd need a specific safety concern to
Heber -
This may depend on who's doing the certification of your equipment. I've
heard of certain agencies ignoring faceplate LEDs, but not yet of any
wanting to test. According to Jerome Dennis of the CDRH (at the 1997
International Laser Safety Conference), discussions at the IEC TC76
As with many things in life, there is no simple answer to your whole
question list, but I'll address what I can in a short form.
A telco is a utility and normally a monopolistic entity. The systems and
equipment the telco use are maintained (supposedly) to a much higher degree
(at least inside
George -
While I have not found myself in quite the same predicament as you describe,
I have had good success with your Option D. This quite often clarifies the
applicable requirements for a product's audit and has also quite often
exposes misunderstanding on the part of the inspector as to what
Jeff -
This rumor doesn't make much sense as an across-the-board requirement,
especially considering UL has a component product category for MOVs and
other transient voltage surge suppressors, along with some product standards
that allow reductions of over-surface and through-air electrical
Mike -
Hearsay alert but it may get this discussion rolling and I'm most
certainly interested in the outcome.
I don't have specifics on IEC 332 and I can not strictly testify to the
accuracy of the following, but from discussions with a coworker in the
UK, EEA countries generally dislike plenum
Doug -
Delta-delta transformers are popular with the utilities for economy's
sake (they are less expensive than WYE transformers) For similar
reasons, some industrial applications distribute and use power within
their plants on delta feeds.
In office environments, however, it's typical to use a
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