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John Gilmer John Gilmer is offline
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Default need to downgrade breaker (from 40amp to 15amp) for new hvac?


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...
On Mon, 25 Jun 2007 10:00:27 -0500, Bud--
wrote:

For motors the rules change. The breaker protects the wire from short
circuits, not overloads, as gfretwell said. Rather arcane rules for
motors are among the reasons why electricians have licenses.



Exactly right Bud.
In fact there is a question on every inspector exam I have taken about
a 115v 1HP motor with internal overload protection (16a FLA) and the
correct answer is "40a breaker, 14 ga wire".
I understand this is an anomally using all the exceptions and "round
up" rules but it is NEC compliant.


Really?

That's plain nuts!

Your run of the mill CB takes seconds to trip just from FLA currents.
There just isn't any need to put a 40 amp breaker on a motor circuit.

If there is something about the motor the keeps it from coming up to speed
in a second or two then fix that. But don't put a 40 amp breaker on #14
wire.