2 or 3 Wire Romex for Central Air Condenser?


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Old 05-07-14, 06:22 PM
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2 or 3 Wire Romex for Central Air Condenser?

Hi,

I currently have the walls open around my main box for some renovations I am doing and while the walls are open, I want to pre-run wiring for adding central air in the future.

For the condenser, I am planning on running #8 Romex but I am not clear if central air condensers usually need 2 or 3 wire Romex (e.g., 8/2 or 8/3). Any insight you have would be very appreciated.

Thanks,
Matt
 
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Old 05-07-14, 06:48 PM
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They are 240 so they need 2 conductor +ground. If there isn't a receptacle within six feet of the location you may also want to run 12-2 for a 120 volt maintenance receptacle.
 
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Old 05-07-14, 07:39 PM
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# 8 is way overkill. You might be able to run #12 or even #14.
 
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Old 05-08-14, 07:22 AM
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Not having any idea of the size of the house or size of any future new A-C unit, I'd be hesitant to run anything smaller than 10-2 /G NM cable
 
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Old 05-08-14, 08:06 AM
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From my experience you can get away with as small as 14-3 for the inside unit and usually 10-3 is good for the outside unit. I've run as large as 6-3 for the outside unit, and dual 6-3 for the inside unit because the inside unit for heat strips. You really need to know the requirements of the air handler and outside unit before running your wiring. You can also get away most likely with */2 cable, too, but I usually run */3 cable in case it would ever be needed.
 
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Old 05-08-14, 10:43 AM
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Thanks for the tips guys.

House is 2 stories and ~2700 sq ft. I am thinking #8 wire for the compressor to be better safe than sorry. At this point, I don't have any idea of the actual compressor I would end up getting in the future and I really don't want to re-open up the walls at that time.

Matt
 
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Old 05-09-14, 10:38 AM
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House is 2 stories and ~2700 sq ft. I am thinking #8 wire for the compressor to be better safe than sorry.
You could do that as long as you won't need two condensing units.
 
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Old 05-09-14, 05:59 PM
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While you have the walls open you should also run a 120 volt line with your A/C line. Code requires a GFCI protected receptacle within 25' of A/C equipment.
 
 

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