PSNet, The US NEC is quite clear that no one appliance can use the entire branch circuit capacity unless it is a dedicated circuit. This is what drives the derating of the allowable current available to any appliance. It is expected that another appliance will be connected into one of the outlets on that circuit. This requirement is embedded into various safety standards, but the root requirement is the NEC. There is an exception allowed: A dedicated circuit may be supplied for a particular appliance and, in that case, the appliance may use the entire capacity of the circuit. A dedicated circuit is one that is specifically run from the breaker box to a specific location and only has one outlet available there. This is generally avoided in that one must hire an electrician to install the dedicated circuit in order to put the equipment into service; and most customers don't want to spend the money for the electrician. Note that you may UL/NRTL List equipment for such use, but you will be required to specifically note the installation restrictions in the installation manual; and you may be required to put a special tag on the power cord with the same information. If the installation is inspected, the inspector will specifically check for the dedicated circuit before passing the installation. Avoiding inspection is more problematic in these times when companies are working harder to have turn-key installations provided by a contractor - who installs the equipment at the same time the construction is being finished which draws the inspectors attention to all this equipment which also must meet the code requirements (read: be Listed). If the installation is not inspected, you should be so lucky, the customer will probably have nuisance tripping of the breaker from any other significant equipment installed on that circuit - which will lead to customer dissatisfaction with you equipment since it isn't reliable and always working when expected.
I have such a circuit in my garage specifically for the freezer; not so much as the freezer needs the entire 15A available from that circuit, but that I don't want some other appliance throwing the breaker and causing the freezer to defrost whereby we would loose the entire store of frozen goods. (That happened to us once before in another house - the circuit blew the first day of a 3 week vacation, according to the neighbor who saw that the full-time light we had left burning was out. Anyway, we had moldy meat in the unit and berry juice running out over the carpet in front of the freezer. We lost most of half a frozen cow plus a year's crop of berries, and had to throw the rug out plus my wife spent most of a month getting the rotten meat smell out of the unit so we could put it back into service. So much for the war stories.) br, Pete Peter E Perkins, PE Principal Product Safety Consultant Tigard, ORe 97281-3427 503/452-1201 fone/fax p.perk...@ieee.org ------------------------------------------- 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org