Central air wiring question
 

The old aluminum wiring for my A/C is oxidized and I'd like to replace it. Based on the info on the tag, I should be able to use a 30A breaker with 12 gauge or larger wire, correct?

Thanks.

http://i1337.photobucket.com/albums/...ps51733a0d.jpg

No. size for your min breaker

The OP is correct, that's the code. And for short distances there's no down side for #12 wire. For longer distances, esp. through hot attics, there is power lost as heat from the resistance in the wire. Upgrade the wire a little and you can recoup your investment with lower bills. By the way, aluminum is a perfectly good conductor. A wire brush, some Noalox grease and a torque screwdriver will make for efficient long lasting connections.

Totally incorrect. #12 on a 30A breaker is just fine in this application. In fact, I'm pretty sure #14 would be allowed since it is actually rated 20A (25A for 90C) but, like #12, is subject to a special maximum breaker size for most types of circuits - but not this one.

12 is fine. Myself I would use a 10, but code allows 12.

What are you talking about, if this was true he should be wiring it with #6 or #4 to save even more money.

:laughing::laughing::laughing::laughing:

Thank you. I do plan on using 10ga.

Thanks for your input. True, aluminum is fine, but since I have the copper, I'd like to just replace it.

If you use a fused disconnect it has to be #10 to the disco, then #12 to the unit. Non fused can be #12 from the panel all the way.

I got it done with 10-2 to the fused disconnect and kept the 8ga whip that was already there.

Thank you everyone.

Depending on what code cycle you are on, you could use #14 AWG. and a 30 amp breaker. :)

Why would you use 10 AWG? It serves no purpose.

No idea how long his run is. but less voltage drop on those hot days when the compressor has to start. Also, don't have to run a new wire down the road if he adds on and needs to increase the size of the A/C to something that has a min cir amp of 25.

No real cost difference between 10 and 12.

yes, there is... :) I personally would wire the unit with 14 AWG.