On Wed, 8 Mar 2006 13:12:01 -0600, Robert Swinney wrote:
A 5 HP single phase motor, on 240 volts, should be fed with a 20 amp double
pole breaker.

Not hardly.

My marathon 5hp is spec'ed at 27.5amps continuous on 230v. It has a
starting surge captured by my peak-reading clamp on ammeter at around
100amps. There is NO WAY it is going to run from a functional 20amp
breaker. Following NEC rules, since no delayed action breaker was
available for my panel, it is currently very happy on a 50amp breaker.

That size breaker would afford full load current protection
for the motor.

I depend on the motor's own overload protection and let the breaker
protect the wiring as that is the way things are designed to work.

Check with local code to be sure what is "right" for your
location.

That at least is very good advice.

sdb
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