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Old 04-26-2009, 09:28 PM   #1
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Wiring AC unit through 20A Disconnect


I am having some issues wiring my Central Air unit.
Currently there is a red two wire 12G wire running from the AC unit to a 20A Non Fusible, Pull Out Disconnect Switch. Then a Orange Two Wire 10G from the Disconnect to the Breaker Panel. The disconnect has four term screws labeled Load/Line on each. The Wire from the machine has Red to Line and Black to Load on one side, the wire to the panel has a White wire to Line and Black to Load.

Once at the breaker, I have wired the white wire to common/trip and the black to the other side of a 2 Pole 20 Amp Circuit Breaker.

I keep tripping the breaker .... What am i doing wrong.
Is it at the disconnect?

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Old 04-26-2009, 09:34 PM   #2
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Wiring AC unit through 20A Disconnect


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I am having some issues wiring my Central Air unit.
Currently there is a red two wire 12G wire running from the AC unit to a 20A Non Fusible, Pull Out Disconnect Switch. Then a Orange Two Wire 10G from the Disconnect to the Breaker Panel. The disconnect has four term screws labeled Load/Line on each. The Wire from the machine has Red to Line and Black to Load on one side, the wire to the panel has a White wire to Line and Black to Load.

Once at the breaker, I have wired the white wire to common/trip and the black to the other side of a 2 Pole 20 Amp Circuit Breaker.

I keep tripping the breaker .... What am i doing wrong.
Is it at the disconnect?
Yes it is at the disconnect. You need to have the wires from the orange cable on the line terminals, and the wires from the red cable on the load terminals.

The way you have it now is a dead short, because each line terminal has a corresponding load terminal. So the black and white from the orange cable are directly connected together through the disconnect.

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Old 04-26-2009, 09:38 PM   #3
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Wiring AC unit through 20A Disconnect


Your wires comeing from the panel have to go to the line side of the disconnect. The wires going to your unit have to be connected to the load side.

I am assumeing this is 220V. most our, you will have to put both the white and black on the 2 pole breaker.

Make sure you check the nameplate and get the minimun circuit capacity and maxium breaker size. The minumun circuit capacity will give you what size wire you need and the maxium breaker size will give you what the largest breaker you can use. The breaker size will be bigger to compensate for startup.
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Old 04-26-2009, 10:05 PM   #4
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Wiring AC unit through 20A Disconnect


Thats awesome guys, thanks ..
So at the breaker ... was i correct connecting the white to common/trip and the black to the other terminal ..

or does it even matter ?
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Old 04-26-2009, 10:19 PM   #5
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Wiring AC unit through 20A Disconnect


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Thats awesome guys, thanks ..
So at the breaker ... was i correct connecting the white to common/trip and the black to the other terminal ..

or does it even matter ?
That is just writing on the breaker case, not an indicator of polarity. For 240 V loads, no, it doesn't matter.
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Old 04-26-2009, 10:40 PM   #6
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Wiring AC unit through 20A Disconnect


You guys are awesome .... thx!

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