tapping into a/c breaker box

can a radon mitigator tap into exterior a/c breaker box for 15amp supply to gfci outlet that runs a radon fan?

No not allowed

Are you talking about the condenser disconect?
How are they protecting that from overcurrent and what are they using for a neutral? OTOH if they are just talking the HVAC service outlet (15 or 20a 120v) it should be fine.

In Canada many home owners shut of the Air Conditioner at the panel in the winter .
This would also shut of the power to the radon mitigator.

I personally don’t think what “could” happen enters into it. Besides, the poster is in the US.

IMO the question is WAY too vague.
If this is a 240v pull out for a condenser, then it absolutely cannot be done.
If this is a small panel with breakers it certainly can be done.
If this is a 120v feed for an air handler it most likely can be done.

There is too little information to answer this accurately.

I thought the a/c should have it’s own dedicated circuit and that nothing should tap into it. Where did I mess this up? :shock:


Thats the way it is In Canada . AC only nothing else .

If the question is…can you TAP into the disconnect for the AC unit outside…NOPE…as Greg stated where will your neutral come from…so that one is easy…in regards to that question…

However, if they are speaking of as peter stated the outside service ( within 25’ ) receptacle then it would probably be fine…

Erol…yes the outside AC unit is dedicated and probably 240V anyway so running the 120V Radon Fan is not going to happen…legally anyway…so we wont go into how it can be done illegally…:slight_smile:

Chances are again as peter stated…if it is an outside AC unit…chances are 240V and not gonna happen…so erase that option…:slight_smile:

I think your thought is solid yet, Erol, I didn’t see anyone condoning tapping into the AC circuit.

This is most certainly NOT written in stone. At least as far as the NEC is concerned. It all depends on the individual appliaction.

In addition to the Condenser 240v feed via disconnect, there’s also a requirement to have another receptacle in the vicinity for ‘servicing’ the HVAC…

I think if its tapped into the servicing receptacle then constant power to the fan would be available w/o affect on the 240v to the Unit itself…

Or I could be suffering heat exhaustion :smiley:

peter I think the only written in stone part is…I don’t know any electricians who would not probably run a dedicated line to the outside units…just easier to do so and what you would see most of the time.

Also I can’t recall seeing ( but then again I am only 37 remember ) any 120V outside AC units…guess the houses I wire are all large…:wink:

Yes mike…within 25’ of the units…if this is the one he is asking about tapping into…then probably fine…

Now they need to understand IF they actually DID find a way to TAP into the AC Disconnect…they are running a wire from it to a fan …and the smaller conductors would not be PROPERLY protected…since the OCPD is sized to the AC unit only…

Just make sure they dont try it and use one of the legs and the EGC as the neutral…oh we have seen THAT before have we not…oh so wrong…Love that saying…well it all goes back to the same location anyway paul…yeah…ok…I hear ya.

In any event one would need to run a 4 wire feed, wouldn’t they?

Nope…we run (3) wires to the AC units all the time…no Neutral needed…so (2) ungrounded conductors and (1) EGC is all that is needed…its not a sub-panel…:slight_smile:

No, Paul, I was referring to tapping into the 240 AC circuit to supply the radon fan question.

Erol didn’t think one could do it.

Speedy said it wasn’t written in stone.

That’s Mr Gault (or Col. Gault if you prefer) there young Whipper Snapper Sparky!:mrgreen: :mrgreen:

lol…ok…let me rephrase it…read my pervious posts…

1.) Chances are if the AC Unit is 240V…nope he should not TAP it because chances are the TAPPED conductors would be smaller than the OCPD that is protecting the AC Circuit to begin with.

2.) 4 conductors would not be needed for the FAN either…BUT the AC unit probably only has (3) conductors running to it as well…so you have to be careful from DIYers who think the EGC is the same as the neutral…and tap one leg of the 240V disconnect and use the EGC as the return path…which is wrong…but I have seen it many times…on DIYers work.

Just making you aware…nothing more…nothing less…

Sorry…tehehhee…I don’t call anyone Mr. anymore…oh wait you are right…I usually call Mr. Decker…Mr. Decker…but then again he is HUGE…can’t piss him off…:slight_smile:

UNless I missed something, the OP has only posted once to this thread. He mentions tapping into an “exterior a/c breaker box”.

We have NO confirmation that this is a straight 240v condenser.
We have it mentioned that this is a “breaker box”.
We have nothing else to go on. All this is speculation.

Of course you would not pull a 120v receptacle from a straight 240v feed. For several reasons. One being there is no neutral and the other being you can’t feed general 125v receptacles from more than a 20 amp circuit. An A/C condenser likely fits both these things.

Some of what I commented on has nothing to do with the OP’s exact situation. A point was made that an A/C circuit must be dedicated. This is a VERY broad statement that is not entirely true. That was what my comment was directed at.

I think my first reply to this thread was ignored.

I ABSOLUTELY did NOT. This is my point. Read ALL the replies…especially my first one!