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AC Low Voltage Control Wire Questions

3 posts in this topic


I'm buying a foreclosed property where the low voltage (24 volt?) control wire to the air conditioner is cut. This is the wire that closes the contactor to start the compressor.

The wire is cut between the place where it exits the exterior wall and where it goes into the outside part of the air conditioner. I suspect a careless landscaper with a power weed trimmer, as the wire is very thin. In any case, I need to replace the wire to get the air conditioner working and I have a few questions:

1. Since this is a low voltage wire, is it legal (in terms of code) to splice the wire with wire nuts outside the house? The home inspector seems to think so, but I'm not sure that's the best idea? In the long term I intend to replace, but if there's a quick and legal way to get the AC to run before closing (it's required to work for an FHA loan), then it might be easier to splice for now and then replace after closing. But only if that's legal.

2. If I rerun this length of wire (and eventually I will), where does the other end of it go to? It's basically a 2 conductor wire. Does it go from the contractor directly to the thermostat, or does it go to the inside of the handler unit?

3. What gauge of wire is required? The run is maybe 30-40'. It's basically from one side of a 2 car garage to the other, plus up and down the walls.

The Unit is a RUUD 2.5 ton, built in 2005. The handler is a 7 KW. I'm not sure how brand specific this question is though.

Thanks in advance for any help you can provide!

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Need appliance parts? Call 877-803-7957 now!

Usually 24v AC

It should be OK, as long as it is "low voltage"

Usually use standard "thermostat wire", available at any hardware store in 2, 3, 4 or more wire varieties.

Usually the "other end" is on the thermostat terminal strip inside the Furnace (or air handler) wiring area.

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Simply go to lowes or home depot and buy 2 or 4 ft of 18 gauge 2 conductor thermostat wire and 2 orange wirenuts.

Turn off power to the heater (so you dont short out the control transformer in the heater.)

Cut the old wire and tie in the new wire to it. then route the new wire along the refrigerant pipe into the outside unit . Remove the old wire and connect the new wire in its place.

Wrap the orange wirenuts with electrical tape so that none of the orange shows( the wirenut will break down from exposure to the sun . Then tape the wire to the underside of the refrigerant pipe (hidden from view) .

Thats it . It is repaired. REMEMBER this is low voltage and as such does not really fall under any " electrical code" rules. Just make it neat and so it does not get wacked again and it will be fine.

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