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 - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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