# 30A Air Conditioner Disconnect



## HooKooDooKu (Jan 7, 2008)

Are you using conduit that is weather proof between the building penetration and the bottom of the disconnect?

If you're using EMT, I don't know if that would be considered "water proof" and therefore not suitable for what I assume is a "wet" location (outdoors in the rain). The disconnect for my AC uses some sort of gray colored flexable conduit between the house and the disconnect. Since there is NM 10/2 running through the basement, and no junction box at the wall penetration, I assum the NM wire continues through this weather protection conduit to the disconnect box.

My disconnect box is then something of a pair of knife like blades (one knife for each of the two hots). The blades are positioned such that you disconnect the power by pulling the "thing" the blades are mounted to. The blades are positioned such that you spin the "thing" around and insert it back into the disconnect. That way, the hots in the disconnect are covered, but the unit is disconnected.

As a guess, the HVAC doesn't want a fussed disconnect because that way you don't have to worry about blowing the fuses (requiring that you either stock the fuses, or run to the local supplier when one of them activates). It's much simpler to only have to worry about tripping a breaker rather than worring about blowing a fuse.


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## JPWMU (Apr 19, 2010)

I was going to use the grey plastic conduit (Sch 40 I believe) from the disconnect to the LB and through the wall. It should be water tight, because I’m going to glue it. It’s the same material that runs from my meter to the LB and through the wall for the main service wires, just smaller diameter. 

The fusible disconnects that I’ve seen are the “knife blade” type as well, but there needs to be a 1/2" +/- fuse in there to make the connection. 

I was thinking that the non-fused disconnect would be beneficial for the exact reasons you mentioned. I just don’t understand why Lowe’s/HD doesn’t carry these right in the same spot. Is there a code issue?


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## Jupe Blue (Nov 9, 2008)

You should be able to get a non-fused disconnect at your local electrical supply wholesale house. They should also sell retail to you.

If you are running cable outside of the house to the disconnect, you must use the type rated for a wet area. You can set a j-box in the basement and transition to UF or just run UF all the way back to the panel.


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## jbfan (Jul 1, 2004)

Not a code issue unless the data plate on the A/C calls for fused protection.
They should be located in the same place, but they may be labeled as a 60 amp disconnect.
You can not run romex inside the conduit.
Mount the disconnect so the cable enters the back of the disconnect.


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## JPWMU (Apr 19, 2010)

Jupe Blue said:


> If you are running cable outside of the house to the disconnect, you must use the type rated for a wet area. You can set a j-box in the basement and transition to UF or just run UF all the way back to the panel.


Even if it's in an enclosed conduit? Can't I use NM-B in a conduit?


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## jbfan (Jul 1, 2004)

JPWMU said:


> Even if it's in an enclosed conduit? Can't I use NM-B in a conduit?


Not in a wet location, and outside the house is a wet location.


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