I wouldn't bother with the 125 amp main unless you found you needed it, and
the wire size probably wouldn't take it. Use larger conduit than you think
you need. You'll need a mortgage right now for the wire, and I wouldn't
bother with a fused disconnect, unless a local code requires it, just use a
60 amp pullout. The 40 amp main will protect it as per the specs



"James "Cubby" Culbertson" wrote in message
...
Hiya Folks,
I'm planning on pulling a permit to install a branch circuit to drive a
new refrigerated A/C compressor. Before I go to the inspector's office
I'd like your opinions on my plan.

I currently have a 125A (rated) panel feeding the house with a 100A Main
breaker. I plan to check the feeders on this to see if I can bump the
Main up to a 125A breaker. I can change a few breaker's around and get
room for a 220 double breaker. I should be ok from a total amperage
standpoint as I don't use the dryer circuit and am on a gas range but by
bumping up to the 125A, I'd be able to leave those intact, I believe. The
electrical specs on the compressor say the RLA (Rated Load Amps) is 20.2,
the LRA (Locked Rotor Amps) is 137 A, the Fuse or HACR Breaker Min is 35 A
and Max is 45 A. I figure I'll put in a 40 A/220V breaker and run a 6/3
THHN feeder via conduit to the location of the compressor approx. 40 ft.
away. I understand I could probably use 8/3 but just in case I ever want
to upsize, I figure the extra cost of the 6/3 is minimal for the length of
run. The feeder would terminate in a fused disconnect mounted on a
unistrut frame with Double Element fuses sized at 175% of RLA (Time Delay
fuses) so they would be 35 A. From there, I'd continue with the feeder to
the equipment via flex. Does this sound like I'm on the right track?
I still have to figure what size conduit (1/2" would prolly work as there
will minimal 90's but 3/4 might just be easier to deal with) and I'm still
a little shaky on the fuse size. I didn't count the Fan Motor Full Load
Amps (1.2A) so that would move the fuse up to 37.45A so I'd probably have
to stick with the 35A fuses. Am I figuring this correctly?

I've given myself a headache searching all the articles in the codebook
but hope I'm on the right track here. Ultimately, the inspector will be
the judge but I appreciate any advice you may have.
Cheers,
cc