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-   -   A/C wiring manual says 14 awg & 20 amp breaker? (http://www.diychatroom.com/f18/c-wiring-manual-says-14-awg-20-amp-breaker-107830/)

brianosaur 06-16-2011 10:45 AM

A/C wiring manual says 14 awg & 20 amp breaker?
 
Wiring a mini-split a/c and the manual says use a 14 awg & 20A breaker.

I ran about twenty feet of 14 awg exterior sheathed solid wire through conduit at the panel through the exterior wall and to the outside condenser unit.

...*then* I read "use a 20A breaker"

I thought I was going to use a 15A breaker.

Can I use a 20A breaker with this wiring?

This is the manual. See page #24 of the .pdf
http://us.lge.com/download/product/f...%29_011607.pdf

Can this unit operate on a 15A breaker?
See page #11 (first column unit LAN091CNP / LAU091CNP)

jbfan 06-16-2011 10:48 AM

Follow the instructions.
14 gauge wire and 20 amp breaker.

brianosaur 06-16-2011 10:50 AM

...yeah but isn't code 12/20?

jbfan 06-16-2011 10:56 AM

Quote:

Originally Posted by brianosaur (Post 668272)
...yeah but isn't code 12/20?

Code is follow the instructions of the manufacturer.

A/C circuits have their own rules about size and ocp

brianosaur 06-16-2011 11:05 AM

ok sounds good :thumbsup:

darren 06-16-2011 05:07 PM

Code will also tell you to use #14 on a 20A breaker.

Your unit does not use more then 15A when it is running, but when it starts it needs the extra bit to get itself going, that is why it goes on a 20A breaker.

Red Squirrel 06-16-2011 05:19 PM

Personally I would try a 15 amp breaker and if it trips then go with the 20. Seems kinda odd they would go against standard conventions though.

SD515 06-16-2011 05:51 PM

As jb mentioned, AC’s have some different rules, and one of them is that a larger breaker can be used than you would typically for a given gauge of wire. I see your line of thinking Red Sq, but if anything should be changed, I would change to 12ga wire. You can always use a larger wire. Not that the OP has too though, as per the instructions.

kbsparky 06-16-2011 07:53 PM

The section of the Code [240.4(D)] that requires 15 Amp max on circuits fed with 14 AWG does not apply in cases of HVAC circuits.

A different section [240.4(G)] applies, where such limitations are removed.

Red Squirrel 06-16-2011 09:33 PM

Quote:

Originally Posted by SD515 (Post 668521)
As jb mentioned, ACís have some different rules, and one of them is that a larger breaker can be used than you would typically for a given gauge of wire. I see your line of thinking Red Sq, but if anything should be changed, I would change to 12ga wire. You can always use a larger wire. Not that the OP has too though, as per the instructions.

Yeah was thinking that too, but figured maybe they said 14 awg because of how the wire connects at the other end or something. But if it's just a screw terminal no reason not to just use 12awg. Or terminate at a junction box then switch to 14awg.

The way I see it, if by chance something else was added to that circuit, you don't want to overload the wire. Now this should not happen in first place, but always good to be safe.

NJMarine 06-17-2011 06:01 AM

Most Minisplits use 14 wire. It listed as a communication cable, which is listed for outside use and is sunlight resistant. Use what the mfg says to use. Some minisplit such as Fujitsu, will not work properly with splices. That info came from Fujitsu tech support.
I just had a cervice call on one of these. There was a splice. Ran new 14 communication wire and the unit worked fine.
The inside unit gets it powewr from the outside unit. There is a signal wire, which tells the outside unit when to turn on or off. This signal is dc and needs a direct connection to each unit.

brianosaur 06-17-2011 09:08 AM

It wasnt in the a/c install manual but,
I also read somewhere that a visible shutoff switch is needed near the outside unit.

Should I put one in along the cable mentioned?

Red Squirrel 06-17-2011 12:45 PM

I would do it just for convinience sake. Good to close it in winter so you don't accidentally turn it on from inside when it is covered.

electures 06-17-2011 03:57 PM

Quote:

Originally Posted by brianosaur (Post 668811)
It wasnt in the a/c install manual but,
I also read somewhere that a visible shutoff switch is needed near the outside unit.

Should I put one in along the cable mentioned?

I disconnect is required within site of the unit. Does not have to be fused unless nameplate requires it. A knife switch will comply.


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