Air Conditioner Disconnect

Apr 04, 2005 14 Replies

If my central air compressor is sitting beneath my service panel (less than six feet) does the code allow the breaker in the service panel itself to serve as the AC disconnect?


If I'm reading the NEC correctly, section 440.14 all that's required is that it be in sight of the unit.



R. Tarin



Yes you can use a breaker for the AC. However, it also seems that you do not have the minimum room required around your panel. 3' clearance in front and 30" to the side.

If I'm reading the NEC correctly, section 440.14 all that's required is that it be in sight of the unit.

R. Tarin

Well, that can be corrected since the unit has yet to be installed. I just didn't want to have to install a redundant disconnnect.

panel (less than

panel itself to

required is that

correct

Seems to me you could have an indoor/outdoor problem - but I can't see your installation. Typically, the service panel is indoors and the compressor outdoors. In that case, a breaker in the panel does not protect the person servicing the A/C. That's the reason for having a disconnect in sight of the A/C. You want the A/C service person to have uncompromizeable control over the feed to the A/C.

Ed

The panel is outdoors. I need only to run a 6' whip to connect. The service panel is totally accessible.

So, you seem to be talking about surface wiring.

You MAY technically be OK.

You are pushing the envelope for LOTS of reasons.

1) In a "normal" installation, the technician SEES the cable running from the unit to the disconnect. When he pulls the disconnect there is no question which was the "right" disconnect.

2) The panel may be accessible but you are asking the tech to either "trust you" that your label is right or take the panel cover off.

3) The disconnect adds a Junction Box there the wires go "airborne" for a foot or two. In many places a different type of cable is used but the box provides a better anchor for the direction change than just another cable clamp or whatever you propose.

4) You installation would not LOOK standard.

Look standard?!? I just remodeled a bank and trust me nothing looks standard.

If you are that nervous use a chase nipple.

So, you seem to be talking about surface wiring.

You MAY technically be OK.

You are pushing the envelope for LOTS of reasons.

1) In a "normal" installation, the technician SEES the cable running from the unit to the disconnect. When he pulls the disconnect there is no question which was the "right" disconnect.

2) The panel may be accessible but you are asking the tech to either "trust you" that your label is right or take the panel cover off.

3) The disconnect adds a Junction Box there the wires go "airborne" for a foot or two. In many places a different type of cable is used but the box provides a better anchor for the direction change than just another cable clamp or whatever you propose.

4) You installation would not LOOK standard.

If the situation allows, I would generally run the wiring through the back of the panel into the crawlspace, and then back out with the lineset. Looks much neater. This will also allow you a little more flexibility layout-wise if you're going with 'carflex' for the whip. Just make sure you label everything properly, including "service disconnect" beside the breaker label.

John

I'm not "nervous." It's not my place.

I also don't know who put in the air conditioner. If it were installed by a "professional" he would put in a disconnect without even thinking twice.

I think the OP said it wasn't set yet.

It would be mighty neighborly for the HVAC contractor to do so, but the practice varies regionally. Especially in union areas where electricians typically install ALL the wiring. Personally I prefer to do it myself since, being ultimately responsible, I'm going to go behind someone else and check their work anyway. Plus I can make sure everything lines up visually.

Circuit breakers for motor protection is not the best situation IMP. The circuit breaker will meet the code for motor protection as discussed. Depending on your FLA the breaker could be over sized for good protection. I like fuses for motors protection cause I can be sure that the fuse will usually react sooner than the breaker. The fuse must be applied for the application for this statement to work. Check with your installer and get the name plate information. The manufacture will state the FLA and the minimum breaker size needed. If the breaker is say a 30 amp and the FLA on the compressor is 18 amps, I would want fuses. I would fuse at 20 amps with a dual element fuse. Your home your dollars. A 30-60 amp pull out disconnect are not all that expensive for protection of my a/c.

I don't think he was talking about using the panel breaker for 'motor protection'. He specifically asked if the panel breaker would meet the requirements for a *disconnect*. Not the same thing as motor protection.

daestrom

for this statement to work.

In any case, an air conditioner with any kind of warrentee would have some kind of "built in" overload protection. Most compressors have thermal CBs inside. Some units shut down when the "high side" pressure exceeds some point.

The disconnect is just a way to be SURE there is no juice going to the outside unit.

FYI. The AC was installed today. The installer was more than thrilled with the method of disconnect. I've known the installer personally for over 25 years and he's been doing this longer than that.

R. Tarin

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