wiring outdoor AC unit


Old 06-07-05, 09:50 AM
Thread Starter
Join Date: May 2005
Posts: 44
wiring outdoor AC unit

Hi All,

I need to wire in an outdoor AC unit. The load is 220 ~ 7amps and the unit needs to be hard wired. What is the best way to do this? Do have to protect the unit with GFCI? The unit will sit right outside close to the house.

Below is a link to the wiring diagram. I have the 9000 unit. I assume L1 and L2 are my two hots and I can see where the ground connects. Does this mean I do not need to pull a neutral? I have a bunch of 14/3 around, can I just pull it and not connect the neutral if that is the case.


Thanks Bob

Last edited by bob_m; 06-07-05 at 12:47 PM.
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Old 06-07-05, 12:14 PM
Join Date: Dec 2004
Location: Minneapolis
Posts: 28
First I am not an electrician but I think I see some misunderstanding on your wiring attempt. First do NOT use 14gauge...Your air conditioner needs 220v and at a miniumum I would use 12 gauge with a 20amp double pole breaker....Using smaller wiring is dangerous and will damage your compressor...(Think of it this way...12gauge or bigger is the same as you going jogging with a 1" pipe in your mouth...14 gauge is the same as going jogging with a drink straw in your mouth...how soon until you keel over?... ) Wiring 220v to an appliance does not need a neutral...you have two "hots" and a ground....

Old 06-07-05, 12:33 PM
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Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,530
The link you posted is broken, so I can't get to the actual instructions. The instructions should tell you what size breaker (OCPD) to use and will probably recommend a wire size.

If it does only draw 7 amps, then #14 would probably be okay for a short distance. It wouldn't hurt to bump up to #12, and I would definately say #12 if the run from the panel is longer than a few feet. Larger wire is always desirable for an appliance that will be running on a continuous basis.

The unit will not require GFCI, nor would it be desirable.

You're correct, no neutral is required for a pure 240V circuit.
Old 06-07-05, 12:53 PM
Thread Starter
Join Date: May 2005
Posts: 44
Thanks Guys,

They recommend 14 or greater on the wire size. I just purchased some 12/2 so that should do the trick. I was just trying to save a few pennies with the 14 I had on hand. You are correct, 12ga will be better in the long run.

Since I will not be runnning a neutral, is it ok for me to use the white as a hot in the 12/2. I believe you wrap some electrical tape around the end of the white to indicated a hot conductor?

Do I need to put in a disconnect outside? What is required by code?

I fixed the link.

Thanks Bob
Old 06-07-05, 01:00 PM
Join Date: Sep 2000
Location: United States
Posts: 18,497
Yes, you can use the white as a hot. Mark both ends of the white insulation with a black magic marker.

In most cases, you need a readily-accessible disconnect within sight of the unit.

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