I'll join the speculation... I think it is also based on the likelihood of undetected damage to the cord leading to a situation. The cord lengths are limited by standards, they are jacketed with materials designed to withstand some abuse, the condition is easily (albeit rarely) inspected by the user, they are not supposed to be physically attached to the wall (so no fear of damage by a metal cable clamp for example), and so on.
The wiring in your walls, by comparison, may be more at risk, since it can't be inspected, it is stapled to the studs, and you're always drilling or pounding nails into walls having no idea whether or not there is wiring behind the drywall. Regards, Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power web: www.xantrex.com <http://www.xantrex.com> Any opinions expressed are those of my invisible friend, who really exists, and frequently has gas. Honest. -----Original Message----- From: Rich Nute [mailto:[email protected]] Sent: Wednesday, October 24, 2001 12:21 PM To: [email protected] Cc: [email protected] Subject: Re: skinny power cords. Hi Gary: Somewhere in my past, I've heard the rationale for this conundrum. I'm just guessing here. Power cords and similar mains devices are sized based on rated load, and are not sized based on fault-condition load. The requirement should be that, under fault conditions, the device is capable of withstanding the fault until the overcurrent device operates without igniting or otherwise causing a hazard. It can get hot; indeed, it can exceed rated temperature under the fault, and it can fail, but it should not ignite or otherwise cause a hazardous condition. A power cord is supposed to be sufficiently robust as to withstand the rigors of use. There are different degrees of robustness according to use. In other words, the power cord itself is not expected to fail under normal conditions of use. So, the power cord should only be subject to load faults. Since the load is protected against faults, the fault-protection in the load also provides fault-protection for the power cord. Best regards, Rich ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
