"Eigenvector" wrote in message
. ..

"Doug Miller" wrote in message
...
In article k.net,
"David Martel" wrote:
RBM,


60 is fine

Is the OP wrong that the #6 line is rated for only 55 amps or are you
saying that a 60 amp breaker is safe with wire that will fail at 55 amps.
Something is wrong here.

Nothing is wrong at all. The NEC specifically permits going up to the
next
higher standard breaker size when the rated ampacity of the wire (55A in
this
case) does not correspond to any standard breaker size.

--
Regards,
Doug Miller (alphageek at milmac dot com)


That doesn't make sense to me at all.

Why allow the breaker to trip at a higher rating than the wire?
Conceivably the wire would fail without the breaker ever tripping. That
presumes the wire rating of 55 A means it is only capable of carrying 55A
at 120V
My cottage had a 23a water heater on #12 for 35 years before I found it and
replaced it with #10.
That is about the worst possible thing, since it comes on at full draw, and
stays on for a long period of time; yet nothing happened. Code is rather
conservative, which prevents many fires.

And don't forget, the wire is 90degree and the panel and breaker are
75degree; yet the 55a limit is as though they were 60degree. So the extra 5
amps is not a big deal.