Service outlet at air conditioning air handler...

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stiege

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Is it compliant to take power from one phase of the 240 feed to the air handler for a service outlet. Before the two pole shut off switch, using the neutral in the three conductor cable?

15 amp double pole breaker.

It was done like this in a previous home and passed inspection.

Thanks in advance,

Jason
 
If you have a 3W cable then you would have 2 hots and a ground. No neutral.

The receptacle tap would be non compliant.

Tapping a HVAC circuit before the disco for a receptacle is common, but you need a 4W cable, 2 hots, 1 neutral and 1 ground.

The feeer circuit must be properly sized for the HVAC and receptacle and the taps properly sized, and the taps and receptacle need an OCPD. 210.21(B).
 
four wire cable... red, black, white and green. 15 amp double pole breaker.

So there is no code citation that prevents this specifically.


Thanks,

Jason
 
jumper said:
The feeer circuit must be properly sized for the HVAC and receptacle and the taps properly sized, and the taps and receptacle need an OCPD. 210.21(B).
Click to expand...

what would be the "proper" sizing of the feeder circuit? would it be 180 VA more than the FLA of the HVAC system?
 
Take a look at 210.23(A)(2).

If you just have an air handler, you are probably under 50% of the branch circuit rating, if you also have a compressor unit - it is a crap shoot.
 
stiege said:
four wire cable... red, black, white and green. 15 amp double pole breaker.

So there is no code citation that prevents this specifically.
Click to expand...

As long as the breaker is common-trip. When mixing 240V and 120V loads on a MWBC, this is important so that the 120V loads on one leg aren't backfed through the 240V load(s) by the other leg, if the breaker on only one legs trips.
 
stiege said:
...
So there is no code citation that prevents this specifically.
...
Click to expand...
As long as the disconnect is not fused. If it is fused, the line side cable is a feeder... and according to many, you can't supply a branch-circuit outlet with a feeder.
 
Smart $ said:
As long as the disconnect is not fused. If it is fused, the line side cable is a feeder... and according to many, you can't supply a branch-circuit outlet with a feeder.
Click to expand...

And according to many others, the wire to the AC is a branch circuit to the AC and a feeder to the separately protected receptacle, with no logical contradiction involved.

The code says that anything meeting definition A is a feeder, anything meeting definition B is a branch.
Since there is nowhere a statement that the two are mutually exclusive a circuit that meets both A and B conditions at the same time is both a branch circuit (and subject to branch circuit articles) and a feeder circuit (and subject to feeder circuit articles.)
If you find a branch circuit requirement and a feeder requirement that cannot both be met at the same time, then you cannot have a circuit which is both. But I have not found such a pair of requirements.
You do not even have to apply any tap rule if you run full feeder sized wire to the load side of the branch OCPD.
 
GoldDigger said:
And according to many others, the wire to the AC is a branch circuit to the AC and a feeder to the separately protected receptacle, with no logical contradiction involved.

The code says that anything meeting definition A is a feeder, anything meeting definition B is a branch.
Since there is nowhere a statement that the two are mutually exclusive a circuit that meets both A and B conditions at the same time is both a branch circuit (and subject to branch circuit articles) and a feeder circuit (and subject to feeder circuit articles.)
If you find a branch circuit requirement and a feeder requirement that cannot both be met at the same time, then you cannot have a circuit which is both. But I have not found such a pair of requirements.
You do not even have to apply any tap rule if you run full feeder sized wire to the load side of the branch OCPD.
Click to expand...

Are not they mutually exclusive by their definitions?

Branch Circuit. The circuit conductors between the final
overcurrent device protecting the circuit and the outlet(s).

Feeder. All circuit conductors between the service equipment,
the source of a separately derived system, or other
power supply source and the final branch-circuit overcurrent.
device.
 
jumper said:
Are not they mutually exclusive by their definitions?

Branch Circuit. The circuit conductors between the final
overcurrent device protecting the circuit and the outlet(s).

Feeder. All circuit conductors between the service equipment,
the source of a separately derived system, or other
power supply source and the final branch-circuit overcurrent.
device.
Click to expand...

If you have a circuit which leaves the load side of OCPD in panel A and goes in parallel to a load and to a fused disconnect for a second load, then the circuit (or at least parts of it) meets both the Branch definition and the Feeder definition.
You are starting out with the implicit assumption that you cannot put a load and an OCPD in parallel and are then using that assumption to try to prove your point.
 
maximum circuit ampacity called for is 4, double pole common trip breaker, disconnect is double pole snap switch in same box as service outlet.

Thanks for all the comments. Electrician is on site next week, hvac installer says it's done all the time. My brother in law who is a licensed electrician says it's a bad idea, but couldn't really give me reason why.
 
jumper said:
If you have a 3W cable then you would have 2 hots and a ground. No neutral.

The receptacle tap would be non compliant.

Tapping a HVAC circuit before the disco for a receptacle is common, but you need a 4W cable, 2 hots, 1 neutral and 1 ground.

The feeer circuit must be properly sized for the HVAC and receptacle and the taps properly sized, and the taps and receptacle need an OCPD. 210.21(B).
Click to expand...

Do you refer to 14/3 as 4 wire cable?
 
stiege said:
Is it compliant to take power from one phase of the 240 feed to the air handler for a service outlet. Before the two pole shut off switch, using the neutral in the three conductor cable?

15 amp double pole breaker.

It was done like this in a previous home and passed inspection.

Thanks in advance,

Jason
Click to expand...

I agree with post #2.

The typical HVAC unit does not have a neutral, it has two hots and a ground. A lot of older installs are wired with SE cable, however the bare conductor is not a neutral and cannot carry current under normal operating conditions. Ranges and dryers installed pre-'96 NEC are also often wired with 3 wire SE cable, and the 120V components inside do make use of the ground as a neutral, however it cannot be done like that anymore.

nm, just read post #3 that says it's a 4 wire feed on a 15A breaker. I dont see a problem with that.

"maximum circuit ampacity called for is 4..."

Huh? 4A is low, and it's usually minimum circuit ampacity and maximum overcurrent protection... I've never heard of a maximum circuit ampacity.
 
jumper said:
Sorta. I call it 3 wire+ground. Depends on who I am talking to.:)
Click to expand...
I find 3 wire (or conductor) with ground works for most. Back when I was just a helper a journeyman told me to pull 2 runs of 3-wire MC and 1 of 4-wire. It was the first time we had worked together. I thought he meant 12-2 and 12-3 MC. Not. Had to replace 2 runs.
 
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