DIYbanter - View Single Post - What size wiring for Central A/C compressor?

The Daring Dufas[_8_]

On 3/4/2013 2:15 PM, wrote:
On Mon, 04 Mar 2013 12:50:54 -0600, The Daring Dufas
wrote:

How often do you deal with electrical and mechanical inspection
services? I've done electrical and HVAC work for a living and I
base my assertions on practical experience where I've worked. It
may be different where you did your electrical and HVAC work for
a living. Perhaps the authorities interpret the NEC differently
where you have done your professional electrical and HVAC work?

TDD

I have been a certified, state licensed electrical inspector for about
20 years.

Florida and we follow the NEC state wide, unaltered, except for
requiring bonding of steel studs.

I said before, this is a common question on the inspector tests and if
you say 8ga on a 40a breaker for a motor circuit like this, you got
that one wrong.
Maybe your inspectors are not certified and it is just the mayor's
nephew who learned his trade from the Time Life electrical wiring for
dummies book.

That's what they want around here with a disconnect at the condensing
unit. I've always gone by the breaker size required by the label on the
unit and sized the wiring for the breaker and that's what the inspectors
want. If you were the inspector at the site, I would do what you
demanded. It can't be simpler than that. Of course, different insulation
types handle different currents. I don't argue with the inspector and do
what their department requires. The inspectors around here would reject
a 40 amp breaker on #10 copper 60°C NM/UF cable. Higher temp rated wire
insulation would be different. NEC Table 310-16. I would put a 40amp
breaker on #10 copper if it has 90°C rated THHN/THWN/XHHW insulation. O_o

TDD