RE: Coaxial cable

[Gary McInturff]

Nicely put, but I want to emphasize one point. The foil in most cables
doesn't have a metal to metal contact. Where the foil overlaps itself the
polyester on the "underside" is what is in contact with the foil "outside".
The type cable you are mentioning is called an  "e" fold if I remember
correctly, but I don't kno why. A lot of folks don't realize that they are
not getting foil to foil contact, just and overlap of material. 
Gary

-Original Message-
From: jrbar...@lexmark.com [mailto:jrbar...@lexmark.com]
Sent: Tuesday, November 07, 2000 8:58 AM
To: sergioro...@siemens.com.br; emc-p...@ieee.org
Subject: Re: Coaxial cable



Sergio,
A "foil & braid" shield is quite common on high-speed cables.  If a cable is
properly terminated and you don't have common-mode problems, most of its
radiated emissions will be from holes in the shield.  Thus "optical
coverage",
the percentage of the shield's nominal area that is actually covered by
wires/conductive  foil, is a reasonable approximation to the shielding
effectiveness.

It is very difficult to braid wires in a way that achieves over 95% optical
coverage.  A foil shield, with the overlap folded over so the conductive
surfaces touch, can easily achieve 100% optical coverage, but is fragile.
If a
foil-shielded cable vibrates, or is repeatedly bent, the foil will
eventually
tear.  Even if end-to-end continuity is retained, this hole in the shield
can
cause a great increase in  radiated emissions.  By braiding wires over the
foil,
you start out with 100% optical coverage, and if/when the foil tears degrade
in
just that area to the 90-95% optical coverage of the braid.

We used to use a type of parallel cable for Electromagnetic Compatibility
(EMC)
testing that had a foil shield.  We would get about three weeks use out of
these
before they went bad and had to be thrown away because of excessive radiated
emissions.   I helped develop and release an IEEE-1284 parallel cable in
1994
(Lexmark partnumber 1329605) that used a foil & braid shield, and we put
these
in our EMC lab.  It took nine months of heavy use before the first of these
cables exhibited a noticeable increase in emissions over brand-new cables.

  John Barnes  Advisory Engineer
  Lexmark International



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Re[2]: EMC Compliance job opening

[Jim Bacher]

forwarding for she...@harbornet.com

Reply Separator
Subject:Re: EMC Compliance job opening
Author: she...@harbornet.com (Sheila A. Schultz)
List-Post: emc-pstc@listserv.ieee.org
Date:   11/7/00 12:22 PM

11/7/2000
Job Title: Senior EMC Compliance Engineer
Company:  Mordue, Allen, Roberts, Bonney, Ltd.  
Location: Seattle, WA


Sr. EMC Compliance Engineer to lead design for EMC compliance for electronic
device manufacturer. Lead field testing and screen room testing. Work closely
with mechanical and electrical engineers on prototype fabrication for this new
product, system grounding layout for low noise performance,electromagnetic
modeling, system integration and PCB layout.

REQUIREMENTS:
* Ability to solve complex problems
* Motivated, self-starter, Team player. 
* Good written and oral communication skills. 
* Minimum BSEE and 2 years experience in design and testing for EMC compliance. 
* Knowledge of EMC standards & testing tools. 
* Knowledge of low noise PCB and system layout techniques. 

Contact:
Sheila A. Schultz  253 851 5355
Mordue, Allen, Roberts, Bonney, Ltd.  
she...@harbornet.com

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RE: Coaxial cable

[jrbarnes]

Richard,
The term that I ran across many times while researching my book was "optical
coverage"-- as though you put a light bulb inside the shield and measured what
percentage of its light leaked out.  The basic assumptions are:
1.  Electric and magnetic fields inside the shield are totally blocked by the
"picks" (conductive wires/strips/foil in a
 group), so the only leakage is through the holes between picks.
2.  The fields that leak out are incoherent, and thus add as scalars (sum of
magnitudes) for the peak leakage.

This is a first-level approximation, and is closely related to a discussion of
the shielding effectiveness of arrays of holes/ honeycomb on this mailing list a
couple of weeks ago.  Over a wide range of frequencies, and far enough away from
the shield that the openings seem to blur together, the leakage is approximately
proportional to how much of the inside/ other side of the shield is exposed to
our view.  But at specific frequencies, or if we get very close to a hole in the
shield,
we get diffraction and constructive-/distructive-interference that cause lobes
and notches in the leakage fields.

Some companies have tried to take advantage of this for special (high-priced)
single-function cables.  "Optimal braiding" selects the gauge and number of
wires in each "pick" (group of wires laid parallel to one another) and carefully
controls their crossing angle during construction of the cable.  The idea is to
create holes with a certain size and shape, and thus polarizability, and with a
certain spacing lengthwise and around the cable.  The authors of the articles
claimed that at the design frequency they would get distructive interference,
just like a diffraction grating, making the holes in the shield appear smaller
than they really were.

The problem that I saw with this scheme was that at other frequencies, or if you
bent/pulled/deformed the cable in any way, the geometry changed and you would
get an *increase* in emissions.  So it always seemed more sensible to me to try
to completely seal the electric and magnetic fields inside the cable/shield and
not optimize just one tiny operating point.

   John Barnes  Advisory Engineer
   Lexmark International
   author of   Electronic System Design:  Interference and Noise
Control Techniques
 (Prentice-Hall, 1987)







richardg%exabyte@interlock.lexmark.com on 11/07/2000 12:11:36 PM

To:   john_barnes.lexm...@sweeper.lex.lexmark.com
cc:(bcc: John Barnes/Lex/Lexmark)
Subject:  RE: Coaxial cable



John,

Couldn't quite follow the "optical coverage" reference. Sounds like it
should be "optimal coverage" for copper wire cable verses optic cable.

Thanks.

Richard Georgerian
Technical Committee 8 Product Safety (TC-8), Vice-chair
Colorado Product Safety Technical Committee (CPSTC), Chair
Product Compliance Engineer
Exabyte
1685 38th Street
Boulder, CO 80301
USA
tel.: 303-417-7537  fax: 303-417-5710mailto:richa...@exabyte.com

-Original Message-
From: jrbar...@lexmark.com [mailto:jrbar...@lexmark.com]
Sent: Tuesday, November 07, 2000 9:58 AM
To: sergioro...@siemens.com.br; emc-p...@ieee.org
Subject: Re: Coaxial cable



Sergio,
A "foil & braid" shield is quite common on high-speed cables.  If a cable is
properly terminated and you don't have common-mode problems, most of its
radiated emissions will be from holes in the shield.  Thus "optical
coverage",
the percentage of the shield's nominal area that is actually covered by
wires/conductive  foil, is a reasonable approximation to the shielding
effectiveness.

It is very difficult to braid wires in a way that achieves over 95% optical
coverage.  A foil shield, with the overlap folded over so the conductive
surfaces touch, can easily achieve 100% optical coverage, but is fragile.
If a
foil-shielded cable vibrates, or is repeatedly bent, the foil will
eventually
tear.  Even if end-to-end continuity is retained, this hole in the shield
can
cause a great increase in  radiated emissions.  By braiding wires over the
foil,
you start out with 100% optical coverage, and if/when the foil tears degrade
in
just that area to the 90-95% optical coverage of the braid.

We used to use a type of parallel cable for Electromagnetic Compatibility
(EMC)
testing that had a foil shield.  We would get about three weeks use out of
these
before they went bad and had to be thrown away because of excessive radiated
emissions.   I helped develop and release an IEEE-1284 parallel cable in
1994
(Lexmark partnumber 1329605) that used a foil & braid shield, and we put
these
in our EMC lab.  It took nine months of heavy use before the first of these
cables exhibited a noticeable increase in emissions over brand-new cables.

  John Barnes  Advisory Engineer
  Lexmark International



---
This message is from the IEEE EMC Socie

Fwd:FW: UL1950 - Clause 2.5.5

[Jim Bacher]

forwarding for ptar...@nortelnetworks.com

Forward Header_
Subject:FW: UL1950 - Clause 2.5.5
Author: "  Peter Tarver   "
List-Post: emc-pstc@listserv.ieee.org
Date:   11/7/00 1:25 PM



-Original Message-
From: Tarver, Peter [SC1:9031:EXCH] 
Sent: Tuesday, November 07, 2000 7:42 AM
To: emc-p...@majordomo.ieee.org
Subject: RE: UL1950 - Clause 2.5.5


Imagine my surprise that an NRTL is asking this question ;>

Since the product is only intended for sale in the US, the NEC accepts green
insulated equipment grounding conductor insulation in power supply cords
[refer to USNEC Section 400-23(b)] and considering that UL wouldn't turn
away a client for US only certification that used a Listed cordset, it
shouldn't be a big issue for you, either.  Perhaps you can make mention of a
relaxation of the requirement in your descriptive report, citing the NEC
reference.

BTW, I've cut open cords and found green/yellow insulation on the earthing
conductor.

Regards,

Peter L. Tarver, PE
ptar...@nortelnetworks.com


-Original Message-
From: Loop, Robert [mailto:rl...@hnt.wylelabs.com]
Sent: Monday, November 06, 2000 7:53 AM

Group,

We are looking at a Class 1, cord connected product that utilizes a NEMA
5-15P plug on one end and is wired to a non-service accessible terminal
block in the rear of the unit with a Recognized compression fitting for
strain relief.  The product is being evaluated against UL1950.

Here's the problem:

The manufacturer only wants to sell the product in the USA and is using a UL
listed cordset with US color code (black/white/green).  Clause 2.5.5
requires that the ground wire be bare or green with a yellow stripe.  They
have expressed an unwillingness to change out the cordset claiming ( in
which my experience agrees) that no one sells a cordset with
black/white/green-yellow color code. 

In order to meet the letter of the clause, we could require them to strip
the 1-1/2 " portion of the green wire that extends past the outer jacketing,
but it seems like a backhanded way of meeting the Clause (does the bare wire
make the product any safer?).

I remember some clause in 1950 making reference to installing the product
"in accordance with the national wiring rules", but can't seem to locate it.
If that's the case, and the NEC does recognize the black/white/green color
code, what's the best answer to resolve this?

Your engineering expertise and enlightenment is always welcomed.


Sincerely,
Robert Loop
Engineering Supervisor
Wyle Laboratories 
Product Safety
ph - (256) 837-4411 x313
fax- (256) 721-0144
e-mail: rl...@hnt.wylelabs.com

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IEEE Atlanta Section / EMCS Meeting on November 15

[DDennis]

REMINDER:
> There will be a joint meeting of the IEEE Atlanta Section and the Atlanta
> Chapter IEEE EMC Society on November 15, 2000.  The specifics are listed
> below:
> Topic: "EMC and the PCB - Fundamental Concepts and Design Techniques"
> Speaker: Mark Montrose of Montrose Compliance Services, Inc. (IEEE EMCS
> Distinguished Lecturer)
> Date: Wednesday November 15, 2000
> Time: 6:30 - 8:00 PM social (sandwiches) and meeting
> Place: Georgia Tech, CRB Conference Room 119, Atlanta, GA (map is
> attached)
> Speaker Information: Mark Montrose is principal consultant of Montrose
> Compliance Services, Inc., and is an IEEE EMC Society Distinguished
> Lecturer. For the last twenty-one years, he has held positions as a
> systems design engineer, product engineer, manufacturing engineer and
> component engineer. He has also held management positions in both
> Regulatory Compliance and Engineering Services. His work experience
> includes design, test and certification of Information Technology
> Equipment and Industrial, Scientific and Medical Equipment, specializing
> in the international arena for the European EMC and Low Voltage
> Directives.
> In 1996, Mr. Montrose authored a best selling reference/textbook, Printed
> Circuit Board Design Techniques for EMC Compliance, published by IEEE
> Press and translated into Japanese by Ohmsha. The second edition was
> released in 2000. His second book, released in 1998, also published by
> IEEE Press, EMC and the Printed Circuit Board - Design, Theory and Layout
> Made Simple discusses in a simplified manner how and why EMI exists within
> a printed circuit board without use of sophisticated math. All books are
> published under the sponsorship of the IEEE EMC Society. In addition, he
> is a contributing author (Chapter 6) for the Electronics Packaging
> Handbook, co-published by IEEE Press and CRC Press, 2000.
> Mark is a member of the Board of Directors of the IEEE Electromagnetic
> Compatibility Society and a Senior Member of the Institute of Electrical
> and Electronic Engineers (IEEE). In addition, he is a director of TC-8
> (Product Safety Technical Committee of the IEEE EMC Society), and member
> of the dB Society. He is an active participant in local, national, and
> international activities of the IEEE and the EMC Society. Mark is a life
> member in the American Radio Relay League with the Amateur Extra Class
> License, K6WJ. Mark has authored and presented numerous papers on printed
> circuit board design, theory, layout, and signal integrity, related to EMC
> and signal integrity at IEEE International EMC Symposiums and Colloquiums
> in North America, Europe and Asia.
> A complete biographical sketch for Mark can be found at
> 
> For Information: David Dennis, Chapter Chair, phone: (678) 775-2435,
> email: mailto:dden...@itsqs.com,
> RSVP's are helpful for planning purposes, but not required
> Non-IEEE members are WELCOME! 
 <> 


GT MAP.pdf
Description: Binary data

Re: Coaxial cable

[Ken Javor]

No.  The foil has lower inductance at high frequencies.  The combination of
foil and braid gives the best protection in a flexible cable.

--
>From: "SERGIO LUIZ DA ROCHA LOURES SERGIO" 
>To: 
>Subject: Coaxial cable
>Date: Tue, Nov 7, 2000, 8:14 AM
>

>
> Group
>
> We are using a coaxial cable with two shields. One is a metallic mesh and
> the other is a aluminium foil. This foil is known as "static foil".
> What is the use of this foil? Is this used for electrostatic reasons?
>
> Regards
>
> Sérgio Rocha Loures
> Siemens Ltda. - Brazil
> ICN FL QEL
> Tel:  +55 41 341-5755
> Fax: +55 41 341-5058
> E-mail: sergioro...@siemens.com.br
>
>
> ---
> This message is from the IEEE EMC Society Product Safety
> Technical Committee emc-pstc discussion list.
>
> To cancel your subscription, send mail to:
>  majord...@ieee.org
> with the single line:
>  unsubscribe emc-pstc
>
> For help, send mail to the list administrators:
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>  Michael Garretson:pstc_ad...@garretson.org
>
> For policy questions, send mail to:
>  Richard Nute:   ri...@ieee.org
>
> 

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Re: Coaxial cable

[jrbarnes]

Sergio,
A "foil & braid" shield is quite common on high-speed cables.  If a cable is
properly terminated and you don't have common-mode problems, most of its
radiated emissions will be from holes in the shield.  Thus "optical coverage",
the percentage of the shield's nominal area that is actually covered by
wires/conductive  foil, is a reasonable approximation to the shielding
effectiveness.

It is very difficult to braid wires in a way that achieves over 95% optical
coverage.  A foil shield, with the overlap folded over so the conductive
surfaces touch, can easily achieve 100% optical coverage, but is fragile.  If a
foil-shielded cable vibrates, or is repeatedly bent, the foil will eventually
tear.  Even if end-to-end continuity is retained, this hole in the shield can
cause a great increase in  radiated emissions.  By braiding wires over the foil,
you start out with 100% optical coverage, and if/when the foil tears degrade in
just that area to the 90-95% optical coverage of the braid.

We used to use a type of parallel cable for Electromagnetic Compatibility (EMC)
testing that had a foil shield.  We would get about three weeks use out of these
before they went bad and had to be thrown away because of excessive radiated
emissions.   I helped develop and release an IEEE-1284 parallel cable in 1994
(Lexmark partnumber 1329605) that used a foil & braid shield, and we put these
in our EMC lab.  It took nine months of heavy use before the first of these
cables exhibited a noticeable increase in emissions over brand-new cables.

  John Barnes  Advisory Engineer
  Lexmark International



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Coaxial cable

[SERGIO LUIZ DA ROCHA LOURES SERGIO]

Group

We are using a coaxial cable with two shields. One is a metallic mesh and the 
other is a aluminium foil. This foil is known as "static foil".
What is the use of this foil? Is this used for electrostatic reasons?

Regards

Sérgio Rocha Loures
Siemens Ltda. - Brazil
ICN FL QEL
Tel:  +55 41 341-5755
Fax: +55 41 341-5058
E-mail: sergioro...@siemens.com.br


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Oct. 20, 2000 EMC/Telco/Product Safety Update Now Available

[Glen Dash]

The Curtis-Straus Update (formerly Conformity-Update) for the week
ending Nov. 3, 2000 is now available at:

http://www.conformity-update.com

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Nov. 3, 2000 EMC/Telco/Product Safety Update Now Available

[Glen Dash]

The Curtis-Straus Update (formerly Conformity-Update) for the week
ending Nov. 3, 2000 is now available at:

http://www.conformity-update.com

---
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RE: Gnd grid

[Allan, James]

For those that don't know, Kemet the capacitor company has a very useful
downloadable capacitor impedance calculator available on their web page. Go
get it and try it,

http://www.kemet.com/kemet/web/homepage/kechome.nsf/vabypagename/spicesoft

Jim Allan
Manager, Engineering Services
Milgo Solutions LLC
1619 N Harrison Parkway
Sunrise, FL, 33323
E-mail james_al...@milgo.com
Phone (954) 846-3720
Fax (954) 846-5693

> -Original Message-
> From: jrbar...@lexmark.com [SMTP:jrbar...@lexmark.com]
> Sent: Monday, November 06, 2000 3:41 PM
> To:   yas...@gega.net; emc-p...@ieee.org
> Subject:  Re: Gnd grid
> 
> 
> Yasser,
> 
> The si-list archives at  http://www.qsl.net/wb6tpu  have a lot of
> information on
>   this and
> 
> related subjects.  Here is a post that I made on power/ground gridding in
> April.
> 
> 
>   John Barnes  Advisory
> Engineer
> 
>   Lexmark International
> 
> 
> 
> 
> 
>>I'm relaying out a pcb for one of my customers. The goal is to
> reduce
>   the cost
>   >by going from 4-layer (internal PWR and GND planes) bd. down to
> 2-layers.
>   One
>   >of the major concerns is increased EMI.
>   >One of the ideas that was brought up to minimize EMI is to have a
> "grid"
>   of
>   >horizontal PWR traces spaced around 2cm from each other on top side
> and
>   >vertical GND traces spaced 2cm on the opposite side. In addition,
> the
>   board
>   >would have a GND ring around the perimeter on both sides that would
> be
>   stiched
>   >with vias. Every point of intersection of these PWR and GND lines
> will
>   have a
>   >.01uF and .1uF bypass cap.
>   >Since I haven't heard about this approach, your input would be
>   appreciated.
> 
> Ilya,
> You would do much better to tightly grid both power and ground, by
> putting:
> *  Horizontal PWR and GND traces topside, next to each other if possible.
> *  Vertical PWR and GND traces bottomside, ditto.
> *  Additional GND traces anywhere you can sneak them in, of whatever width
> will
> fit.
> *  Vias connecting the topside and bottomside PWR traces wherever they
> cross, as
> close as possible to the power
>pins of the IC's and connectors.
> *  Vias connecting the topside and bottomside GND traces wherever they
> cross, as
> close as possible to the ground
>pins of the IC's and connectors.
> 
> I also like to put a ground ring around the board on each layer, and tie
> these
> ground rings together with vias about every 1/2 inch (1.2cm), irregularly
> spaced.  This style of gridding will give you low inductance in both PWR
> and
> GND.  For any direction of current flow within a grid you have multiple
> paths,
> widely spaced so their mutual inductance is low.  Therefore the effective
> partial inductance between any two points is the partial inductance of any
> one
> path divided by the number of parallel paths between the points.  For
> power
> going out to a device, it can return by a parallel ground path which has
> high
> mutual inductance and therefore low overall loop inductance/impedance.
> You do
> lose much of the capacitance between power and ground planes that you
> would have
> on a multilayer board, but for a four-layer FR-4 board that amounts to
> only
> about 100pF/square inch (15 pf/square cm).
> 
> After gridding, an overall view of the board might look like (V=via,
> P=power
> trace, G=ground trace):
> 
> 
>  overall grids =   ground grid   + power grid
> +--+  +--+
> +--+
> !VGGVGVVVGV!  !VGGVGVVVGV!  !
> !
> !GVPGPGVPPPGVPPPGVPPPVG!  !G  G GGG G!  ! VVVVPPPV
> !
> !GP G GP   GP   GP   PG!  !G  G GGG G!  ! PPPP   P
> !
> !GP G GP   GP   GP   PG!  !G  G GGG G!  ! PPPP   P
> !
> !GP G GP   GP   GP   PG!  !G  G GGG G!  ! PPPP   P
> !
> !VGGVGVGGVGVVGV!  !VGGVGVGGVGVVGV!  ! PPPP   P
> !
> !GVPPPGVPGPGVPPPGVPPPVG!  !GG  G GG G!  ! VVVVPPPV
> !
> !GP   GP G GP   GP   PG!  !GG  G GG G!  ! PPPP   P
> !
> !GP   GP G VVP   PG!  !GG  G VV G!  ! PPPP   P
> !
> !GP   GP G GP   GP   PG!  !GG  G GG G!  ! PPPP   P
> !
> !VVGGVGVVGV!  !VVGGVGVVGV!  ! PPPP   P
> !
> !GVPPPGVPPPGVPPPGVPPPVG!  !GGGG G!  ! VVVVPPPV
> !
> !GP   GP   GP   GP   PG!  !GGGG G!  ! PPPP   P
> !
> !GP   VVP   GP   PG!  !GVVG G!  ! PPPP   P
> !
> !GP   GP   GP   GP   PG!  !GGGG G!  ! PPPP   P
> !
> !GVPPPGVPPPGVPPPGVPPPVG!  !GGGG G!  ! VVVVPPPV
> !
> !VVVVGV!  !VVVV

RE: R&TTE Interpetation question

[WOODS]

The commission covered this question in their explanatory document. If a
harmonized standard exists for the radio suites, then there is no need to
consult with a Notified Body nor is there a need to apply the number of the
Notified Body after the CE marking. 

The document can be found at
http://europa.eu.int/comm/enterprise/rtte/infor.htm
 

Richard Woods

--
From:  Kevin Harris [SMTP:harr...@dscltd.com]
Sent:  Monday, November 06, 2000 4:55 PM
To:  EMC-PSTC (E-mail)
Subject:  R&TTE Interpetation question


Hello group,

I have an interpretation question for you. In Annex III of this
document is
says " The identification of the test suites that are considered to
be
essential is the responsibility of the notified body chosen by the
manufacturer except where the test suites are defined in the
harmonised
standards" Does this mean if I have a harmonised standard and I want
to take
the Annex III route can I chose not to use a notified body or does
this mean
that all the notified body's job in this case is to list the
harmonised
standard (nice job if you can get it :-)))?


Best Regards,


Kevin Harris
Manager, Approval Services
Digital Security Controls
3301 Langstaff Road
Concord, Ontario
CANADA
L4K 4L2

Tel: +1 905 760 3000 Ext. 2378
Fax +1 905 760 3020

Email: harr...@dscltd.com  

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Re: UL1950 - Clause 2.5.5 - green/yell sleeving

[Eric Monk]

Hi Robert.

I do not know about availability in the US but in the UK 
green/yellow electrical grade sleeving is available in various 
diameters (100 m reel lengths).
A short length of green/yellow sleeving over the earth  where 
the cord is stripped back  may be a solution to your 
problem. 
Would probably require to be secured with adhesive ?

The sleeving is primarily intended for the electrical installation 
contractors market where twin and ECC cable is terminated in sockets/ 
light switches etc. and there is a requirement in the 
national IEE electrical wiring regulations BS7671
that the bare ECCs should be insulated and identified. 
(and used anywhere else an Earth Continuity Conductor (ECC) conductor 
needs to be identified)

Eric.

On  6 Nov 00 at 9:53, Loop, Robert wrote:

> 
> Group,
> 
> We are looking at a Class 1, cord connected product that utilizes a NEMA
> 5-15P plug on one end and is wired to a non-service accessible terminal
> block in the rear of the unit with a Recognized compression fitting for
> strain relief.  The product is being evaluated against UL1950.
> 
> Here's the problem:
> 
> The manufacturer only wants to sell the product in the USA and is using a UL
> listed cordset with US color code (black/white/green).  Clause 2.5.5
> requires that the ground wire be bare or green with a yellow stripe.  They
> have expressed an unwillingness to change out the cordset claiming ( in
> which my experience agrees) that no one sells a cordset with
> black/white/green-yellow color code. 
> 
> In order to meet the letter of the clause, we could require them to strip
> the 1-1/2 " portion of the green wire that extends past the outer jacketing,
> but it seems like a backhanded way of meeting the Clause (does the bare wire
> make the product any safer?).
> 
> I remember some clause in 1950 making reference to installing the product
> "in accordance with the national wiring rules", but can't seem to locate it.
> If that's the case, and the NEC does recognize the black/white/green color
> code, what's the best answer to resolve this?
> 
> Your engineering expertise and enlightenment is always welcomed.
> 
> 
> Sincerely,
> Robert Loop
> Engineering Supervisor
> Wyle Laboratories 
> Product Safety
> ph - (256) 837-4411 x313
> fax- (256) 721-0144
> e-mail: rl...@hnt.wylelabs.com
> 
> 
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> 
> 

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