Which Wire From The Main Breaker To The A/C Condenser? - HVAC - DIY Chatroom Home Improvement Forum

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Old 10-15-2008, 08:10 AM   #1
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Which wire from the main breaker to the A/C condenser?

I am installing electrical for a new A/C system on a residential rehab project. I am confused about running power from the main breaker box to the 2.5 ton condenser. I was told I needed a 220 line with a double 20A breaker. Because I am running less than twenty feet away, I was told to purchase 10/2 or 12/2 outdoor wire. I must be missing something. Typically, a 220 line has 2-hot wires to attach to the respective contacts on the double breaker. Obviously, 2-wire has only 1-hot conductor. My confusion does not end there. If I were to use 10/3 or 12/3 wire, which would accommodate the breaker, there are only two leads at the condenser whip/disconnect box to tie back into. How do I resolve this?


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Old 10-15-2008, 09:44 AM   #2
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the 2 wire will be blk/white + copper ground,but still able to handle your load run out.the 3 wire will give you the blk/white/red and that copper ground $$$......blk/red for the 220volts single phase,and an optional neutral but it is 220V out there and you'll end up not hooking it to anything in the condenser,and the copper ground will screw into the cabinet.so go with the 2 wire and tape the white over with red at both ends or maybe you can get a 2 wire with the blk/red already...it is the sizing of the wire #10 or #12 thats critical the colores are for inspections and service people latter on to ID.if i went up to a condenser with a blk/white into the L of a contactor i would think this guy could of used any color to wrap the white to signify 220V..even a red marker to paint the wire6" from the connections at both ends.


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Old 10-15-2008, 01:33 PM   #3
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The guy that told you to get 10/2, meant 10/2 with ground.

As above.
By code, the white wire must be made a different color, other then white, or green.
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air conditioning , heating and cooling , hvac , service panel , wiring

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