Type of Wire for 60a supply

[black00lightning]

I getting a 2 tone heat pump installed in my 30' * 32' woodshop. Contractor says I need a 25a circuit for the outside unit and 60a for the inside unit.

25a : I have some 10-3 Romex wire I plan on using even though the neutral is not needed. I'll run the Romex to the disconnect box. What should run to the unit? Run is 60 feet.

60a: Run is 35 feet. I figure on running 6 gauge copper. Should I use a Romex type? Any thought on wire selection? Thanks.

 

[Mustang51js]

Doesn't seem right as usually the outside is more amps than the inside,I would double check that. But if it is right then you are right with the wire size,better off using romex since you won't save much getting al ser cable

 

[Norcal]

Doesn't seem right as usually the outside is more amps than the inside,I would double check that. But if it is right then you are right with the wire size,better off using romex since you won't save much getting al ser cable

Am going to assume electric back up heat, so the indoor unit would have larger requirements then the condenser outdoors.

 

[pattenp]

Clarify the run to the outside unit. Isn't the disconnect outside by the unit? Are you saying the 60ft is from the disconnect to the outside unit? Romex should not be run outside in damp/wet areas.

 

[theoldwizard1]

What kind of heat pump ? A mini-split even with 2 air handlers would draw less current (cheaper to operate). And if you chose the proper high efficiency mini-split, you will NOT need any resistance heat (HUGE operational savings).

 

[mike93lx]

Those are huge current requirements, wow.

My 2 ton mini split has a 20a 240v line.

 

[Joe100]

I would run #4 gauge and #8 gauge in conduit, that's just my own preference. For sure no romex use UF cable. Good job when done.

 

[Speedy Petey]

I would run #4 gauge and #8 gauge in conduit, that's just my own preference. For sure no romex use UF cable. Good job when done.

WHAT????
Please, do not give any more electrical advice if this is what you would suggest for this application.
Just wow!

 

[Speedy Petey]

I agree 25A seems high for 2T, but I bet that's the max breaker rating. Although most 2T I have seen the max breaker is less than 20A. Could be an inefficient unit since it's only a shop.

Agreed, the inside unit almost certainly has electric backup heat. That's the only explanation for the high amperage.

black00lightning, those runs are pretty short, so voltage drop is not an issue. We'd need to know the "minimum circuit ampacity" and "maximum fuse or circuit breaker" ratings of both units to give accurate advice.

 

[wyliesdiesels]

I would run #4 gauge and #8 gauge in conduit, that's just my own preference. For sure no romex use UF cable. Good job when done.

#4 cu for a 60a circuit and #8 cu for a 25a circuit? And UF cable? Thats a HUGE waste of money!

 

[black00lightning]

The unit will be a Carrier 2 ton heat pump with a 10kw heat pack. I asked the contractor what electrical requirements were needed and he asked for what I stated in original post. The romex for the outside unit feed through the brick wall to the disconnect box. I need to know what to use from the box to the unit.

For the inside air handler in the attic (not a mini split) the run is approximately 35 feet. Hope this helps.

 

[pattenp]

You can use #4 Al SE for the inside to air handler and use a #10 Cu AC whip to outside condenser from disconnect.

 

[brewchief]

Use #10 thhn/thwn inside of liquidtight flexible conduit. You can buy a premade whip in 4' and 6' lengths cheaper then you can buy the parts in most cases.
http://www.homedepot.com/p/AFC-Cable-Systems-Liquidtite-1-2-in-x-6-ft-AC-Whip-8015-HD/202286686

 

[black00lightning]

Thanks guys. I have a whip kit with fittings I bought at Ace for the water heater I'm installing in the shop, so I'll just buy one more.

 

[Norcal]

The unit will be a Carrier 2 ton heat pump with a 10kw heat pack. I asked the contractor what electrical requirements were needed and he asked for what I stated in original post. The romex for the outside unit feed through the brick wall to the disconnect box. I need to know what to use from the box to the unit.

For the inside air handler in the attic (not a mini split) the run is approximately 35 feet. Hope this helps.

On the condensing unit (outdoor unit) there is a label that will state the minimum circuit ampere, and maximum overcurrent protection.



The above unit is a cooling only 4 ton unit, min amperes 18.3, max overcurrent protection 30A (3 phase) could have been wired w/ 14 AWG but since it was not a bid job & only needed 25' of MC cable so used 10/3.