Gary,
It was always my understanding that house fuses/breakers were to protect
all the upstream stuff, e.g. service entry box, external transformers etc.
They cannot realistically protect downstream stuff, as they have no
knowledge of how much current is too much for a given appliance. However,
the house wiring should be able to carry a current up to that of the fuse
or CB rating.
ITE manufacturers must protect their own product by the use of incoming
fuses, CBs, etc. A fixed line cord is part of the product. Hence, the
product fuse must blow before a "skinny" line cord on the product would
melt down. For example, suppose a device is rated to draw 2.5A (electric
razor?) and uses a "skinny" line cord at that rating. If an internal
fault draws 14A, it might melt down the cord or the device, but it should
not harm house wiring rated up to 15A.
Of course, I have been wrong before. I think it was 1961.
George
---------------------- Forwarded by George Alspaugh/Lex/Lexmark on 10/24/2001
02:31 PM ---------------------------
Gary McInturff <gary.mcinturff%[email protected]> on
10/24/2001 12:06:00 PM
Please respond to Gary McInturff
<gary.mcinturff%[email protected]>
To: "EMC-PSTC (E-mail)" <emc-pstc%[email protected]>
cc: (bcc: George Alspaugh/Lex/Lexmark)
Subject: skinny power cords.
Fuses and breakers etc, are provided to protect the wiring
downstream from these devices. A 15 amp breaker is allowed to have 14 AWG
wire attached and run all though my house, and terminates in a 15 amp rated
receptacle - parallel blade with ground pin.
Why then can I plug in a computer that has only a 6 or 10 amp rated
power cord? Surely, its not because the computer has supplemental fusing at
2 amps or whatever. That 2 amp fuse can't protect the wiring between it and
the 15 amp breaker in my garage from prolonged operation at 15 amps. The
breaker is completely happy running at that value so the wire just sits
there and cooks!
One would think that any cord rated less than 15 amps, would have
to be terminated in a plug that doesn't mate with the wall outlet, much like
a 15 amp connector plugged into a 20 amp outlet.
Gary
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