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sgip2000 10-07-2012 12:22 AM

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

Dierte 10-07-2012 12:55 AM

No. size for your min breaker

Glennsparky 10-07-2012 03:10 AM

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.

mpoulton 10-07-2012 03:55 AM

Quote:

Originally Posted by Dierte (Post 1025592)
No. size for your min breaker

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.

beenthere 10-07-2012 05:08 AM

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

darren 10-07-2012 07:56 AM

Quote:

Originally Posted by Glennsparky (Post 1025601)
Upgrade the wire a little and you can recoup your investment with lower bills.



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

hammerlane 10-07-2012 08:26 AM

Quote:

Originally Posted by darren (Post 1025668)
if this was true he should be wiring it with #6 or #4 to save even more money.

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

sgip2000 10-07-2012 09:00 AM

Quote:

Originally Posted by beenthere (Post 1025613)
12 is fine. Myself I would use a 10, but code allows 12.

Thank you. I do plan on using 10ga.

sgip2000 10-07-2012 09:03 AM

Quote:

Originally Posted by Glennsparky (Post 1025601)
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.

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

electures 10-07-2012 10:57 AM

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.

sgip2000 10-07-2012 05:32 PM

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

Thank you everyone.

stickboy1375 10-07-2012 06:27 PM

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

stickboy1375 10-07-2012 06:28 PM

Quote:

Originally Posted by beenthere (Post 1025613)
12 is fine. Myself I would use a 10, but code allows 12.

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

beenthere 10-07-2012 06:47 PM

Quote:

Originally Posted by stickboy1375 (Post 1026083)
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.

stickboy1375 10-07-2012 06:49 PM

Quote:

Originally Posted by beenthere (Post 1026099)

No real cost difference between 10 and 12.

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


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