Electrical Engineering - Re: electric outlet for window AC question

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Re: electric outlet for window AC question

Bud

2005-06-28, 6:25 pm

w_tom wrote:

quote:

> indago wrote:
>
>
> Where do these numbers come from? 15 amp wire cannot blow a
> 20 amp breaker? Nonsense. From Automatic Electric, the
> continuous current for fusing a copper 18 AWG wire is 82.9
> amps. Therefore an 18 AWG wire can carry more than 82
> intermittent amps - for the milliseconds necessary to trip a
> breaker.
>

It actually takes a lot longer than one might guess to trip a breaker
(or fuse). Most circuit breakers have a thermal trip element, which is
like a fuse with a time delay - it won't trip, for example, on a motor
start. For Sqare D, 80 amps on 20 amp breaker has a minimum clearing
time of 6 seconds. Above 200 amps the maximum clearing time is 1 cycle.

Bud--

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