Hi Guys,

This is great information and is a perfect example of what I'd like to bring to 
ISPCE 2015 Symposium.  We are having a Design for Compliance/Compliance 101 
type track to try to expand our attendees to Designers and this subject is 
perfect for it and can easily be turned into a 45 minute power point 
presentation.  Any takers??

John Allen (from the USA)
IEEE PSES
2015 Symposium Chair

PS - If you make your device with keyhole slots it becomes removable without a 
tool and is therefore not considered permanent.  Then you can use a Power cord 
vs hard wiring it.  This is often done in Lighting.  Not sure what other 
Standards say about it, but believe most are the same.

-----Original Message-----
From: Don Gies [mailto:don.g...@alcatel-lucent.com] 
Sent: Wednesday, July 30, 2014 8:04 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NRTL / OSHA interpretation of UL60950 clause 3.2.3

Expanding on Ted Eckert's citation of NEC 400.7 (Flexible Cords - Uses 
Permitted), it is useful to cite NEC 400.8 (Flexible Cords- Uses Not 
Permitted).  Most articles of the NEC state uses twice, as "uses permitted"
and "uses not permitted:"

400.8 Uses Not Permitted. Unless specifically permitted in 400.7, flexible 
cords and cables shall not be used for the
following:
(1) As a substitute for the fixed wiring of a structure
(2) Where run through holes in walls, structural ceilings, suspended ceilings, 
dropped ceilings, or floors
(3) Where run through doorways, windows, or similar openings
(4) Where attached to building surfaces
Exception to (4): Flexible cord and cable shall be permitted to be attached to 
building surfaces in accordance with the provisions of 368.56(B)
(5) Where concealed by walls, floors, or ceilings or located above suspended or 
dropped ceilings
(6) Where installed in raceways, except as otherwise permitted in this Code
(7) Where subject to physical damage
400.9 Splices. Flexible cord shall be used

In the above, Items (1) and (4) are the reason you are not using a flexible 
cord for permanent connection to the mains. 368.56(B) would not apply to 
pico-cells (it is in the "Busways" article).

I have had clients and end customers (wireless service providers) insist on 
"connectorization" for bringing power to outdoor remote radio heads, because 
they do not want to send an electrician up a cell tower to interchange the 
equipment. Besides using a NRTL-Listed, outdoor rated AC or DC appliance inlet 
(very difficult to find), we have used the "pendant" philosophy somewhat 
liberally.  "Pendant" is not defined anywhere in the NEC, but it is generally 
assumed to be a flexible cord fixed on one end with a receptacle on the other 
end.  For the pendant powering, we assume the cord-side mate for the appliance 
inlet to be the receptacle.  Also, to reinforce our intent, we mention in our 
installation documentation that it is our intent that the equipment use a 
pendant in accordance with Article 400 of the NEC and Rule 4-012 of the 
Canadian Electrical Code, Part I. We would supply the mating connector, but 
expect the service provider to use their own cord to run power from their !
 distribution box over to the radio head.

Best regards,


DON GIES
ALCATEL-LUCENT
SENIOR PRODUCT COMPLIANCE ENGINEER
GLOBAL PRODUCT COMPLIANCE LABORATORY
600-700 Mountain Avenue
Room 5B-104
Murray Hill, NJ 07974-0636 USA
Phone: +1 908 582 5978
Fax: +1 908 582 0582
don.g...@alcatel-lucent.com


-----Original Message-----
From: John Allen [mailto:john_e_al...@blueyonder.co.uk]
Sent: Tuesday, July 29, 2014 2:43 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NRTL / OSHA interpretation of UL60950 clause 3.2.3

Can anyone explain or speculate as to WHY the NEC does not appear to allow cord 
connection of stationary/fixed equipment because it's a perfectly "legal" way 
of connection in the UK (and probably other countries), and is regularly done 
with items like central heating boilers, instantaneous water heaters and so on 
(provided that the cord outlet is fitted with a manually-operable d/p isolating 
switch, generally incorporating a fuse, to enable it to be completely isolated 
)?

John Allen
W. London, UK

-----Original Message-----
From: Ted Eckert [mailto:ted.eck...@microsoft.com]
Sent: 29 July 2014 14:13
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NRTL / OSHA interpretation of UL60950 clause 3.2.3

The United States national differences are based off of NFPA 70, also known as 
the National Electrical Code or NEC. In theory, all NRTLs are obligated to 
ensure that the products they approve to UL 60950-1 or UL 60950-22 comply with 
NEC. Not all NRTLs are as strict about it, but it is possible that the NRTL in 
question is properly reading the NEC.

NFPA 70 Section 400 covers flexible cords and cables. Section 400.7 covers 
permitted uses and 400.8 lists prohibited uses. You may be able to use
400.7(6) or 400.7(8) to argue for a flexible cord on your product. If not,
400.7(10) may be a possibility, but you would need to review section 645, 
Information Technology Equipment and chapter 8, Communication Systems, to see 
if there is something that would allow flexible cord on your product.

400.7 Uses Permitted.
(A) Uses. Flexible cords and cables shall be used only for the following:
(1) Pendants
(2) Wiring of luminaires
(3) Connection of portable luminaires, portable and mobile signs, or appliances
(4) Elevator cables
(5) Wiring of cranes and hoists
(6) Connection of utilization equipment to facilitate frequent interchange
(7) Prevention of the transmission of noise or vibration
(8) Appliances where the fastening means and mechanical connections are 
specifically designed to permit ready removal for maintenance and repair, and 
the appliance is intended or identified for flexible cord connection
(9) Connection of moving parts
(10) Where specifically permitted elsewhere in this Code

I have run into a few cases where an NRTL has allowed a flexible cord 
connection on a product based on a liberal interpretation of the NEC, yet the 
local electrical inspector then prohibited the product from being connected 
because it did not comply with the NEC. 

The prohibition of flexible cord connections for many products is a historical 
artifact of the NEC. There was a safety basis long ago, but I'm not sure that I 
could argue that the rationale is still valid. I'm not arguing that the NEC is 
right or wrong. This is only what I have experienced from similar issues.

Ted Eckert
Compliance Engineer
Microsoft Corporation
ted.eck...@microsoft.com

The opinions expressed are my own and do not necessarily reflect those of my 
employer.
-----Original Message-----
From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
Sent: Tuesday, July 29, 2014 2:31 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] NRTL / OSHA interpretation of UL60950 clause 3.2.3

In message <6af0cb17eff94b31971265f87afee...@thhste15d1be4.hs20.net>,
dated Tue, 29 Jul 2014, Charlie Blackham <char...@sulisconsultants.com>
writes:

>I was going off memory, and have had another look at the standard:
>
>The equipment is "Stationary Equipment" as it is not "movable 
>equipment" due to it being bolted to a mast or pole. However, 
>Stationary Equipment" can be  pluggable in UL60950-1 - I'm just 
>wondering whether it has to be permanently connected in UL60950-22 
>(which I don't have)

I don't see anything in the IEC version of 60950-22 that demands permanent 
connection. The clause is short but not easy to interpret as it refers to
3.3 of IEC 60950-1 for one case and IEC 60364 for another, but the cases are 
not easy to distinguish.
--
OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Quid 
faciamus nisi sit?
John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

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