5 Ton A/C

[mtnelectrical]

What you guys usually charge for wiring a 5 Ton A/C, with fusable Disco 40' from panel and air handler 25' from panel?(Of course with emergency switch included) All accesible for wiring. Thanks

[U. P. Chuck Electric]

from $750 & up

[jjhoward]

What ampacity wire, what size breaker for the compressor?
What size circuit for the air handler?
Is there room in the existing panel?

[j_erickson]

$750 seems about right. What are you refering to as emergency switch? Is it an oiled fired warm air furnace?

[goldstar]

You have to estimate how much time it will take you to complete but $750.00 seems to be a fairly good # based on the distance of the runs you have. Don't forget to include the breakers in your estimate. If it's AC only (no heat) it's a 240 volt circuit for the AHU. Ten amps per ton is the usual rule of thumb for the condenser but check the nameplate rating anyway.

[mtnelectrical]

Well its 31.5 Amps circuit with max 50 Amps breaker on nameplate, I am running 8 Ga and 40 Amps breaker, furnace is gas (air handler) and it requires a safety switch with 20 amps CB. There is no room for a/c compressor breaker so I am changing 2 breaker with the tandem type to have room for my double pole.H O will pay the permit and wait for inspector this is a town where the inspector tells you to wait for him from 10 to 3 p.m so I just would seal the permit and let the HO handle it.

[LarryFine]

Well its 31.5 Amps circuit with max 50 Amps breaker on nameplate, I am running 8 Ga and 40 Amps breaker, . . .
You could use #10 (except TW or UF) and a 50-amp breaker, believe it or not.

[infinity]

You could use #10 (except TW or UF) and a 50-amp breaker, believe it or not.

You couldn't use NM either.

[goldstar]

There is no room for a/c compressor breaker so I am changing 2 breaker with the tandem type to have room for my double pole.
Make sure the panel will accept and is rated for tandem breakers. The onus is on you to prove that it is. I got knocked down in Ridgewood for this not too long ago. The HO had already installed tandems and I added to them but ended up installing a sub-panel and removing his tandems so I could pass inspection.

You couldn't use NM either.
Do you mean outside the house and within the whip to the condenser or inside the house to the disconnect ? Please explain.

[mtnelectrical]

how the customer took the extra? or you did it just to pass inspection?
And I believe your not supposed to use NM in the whip,it is not rated for Wet location

[infinity]

.Do you mean outside the house and within the whip to the condenser or inside the house to the disconnect ? Please explain.

I mean if you're using #10 NM cable. Larry had posted that you could use #10 conductors, just not TW or UF. I'm adding to that you can't use #10 NM since like TW and UF, it has to be used at the 60 degree C ampacity. At 60 degrees C the ampacity is 30 amps. This is below the 31.5 MCA that was posted.

[goldstar]

If you strip the jacket off NM cable, what is the type of insulation and rating of the conductors inside ? I always thought it was THHN and 90 degrees. Am I wrong ?

[hillbilly]

If you strip the jacket off NM cable, what is the type of insulation and rating of the conductors inside ? I always thought it was THHN and 90 degrees. Am I wrong ?

NM-B, NMC-B, and NMS-B have conductors rated for 90C. That "B" is the Key (hey...a rhyme).
If you strip the outer cover off, there's no way to prove it because the conductor insulation is not marked. The inspectors that I know probably wouldn't take your word for it.
THHN..??? who knows?, it doesn't have to be.
If somebody does know, I'd be interested in learning.
steve