Split 110v off a 230v branch circuit?

[jeffeverde]

Is it possible to split out a 110v branch from a 230v branch circuit? I'd like to put an exterior light and 15A receptacle near my A/C compressor, but it's a 120' run back to the panel, and access it difficult.

I've got a 230v/50A circuit supplying the A/C compressor and the compressor only requries 35A, so overloading the 50A circuit isn't an issue. The A/C circuit terminates in a fused disconnect box, and then a whip into the unit.

[jadnashua]

Not sure if this is legal, but would only be possible if they ran a neutral. If you only have two wires and ground, then no. If you have three wires plus ground, then yes. From neutral to one hot is 120vac. You'd get the same 120vac from one hot to ground, but that would not be code or safe

[jeffeverde]

The 230v circuit is #6-3 w/ground. This will be inspected, so along with safety, code compliance is also important.

[arfeller]

So, if i understand correctly, you have a 6/3 + ground. So two (2) hots, one (1) neutral, and one (1) ground going to the compressor?

If you do have the neutral then splitting out a 110 v ciruit should not be a problem. However, you might run into problems with the fused box.

I had a fused box that would not support splitting a circuit like that so had to replace it with a subpanel. They are pretty cheap ~$35 at home depot + another ~$30 for breakers you might need.

I recently ran 2x #6 hot, 1x #8 neutral, and 1x #10 ground to a subpanel and have a 220v circuit and two 110 v circuits.

I'm not an electrician and am only speaking from DIY projects i have recently done.

So make sure and get comformation of this

[Scuba_Dave]

You want to put a branch circuit on a 50a breaker ?

[drick]

Remove your outdoor A/C disconnect and replace it with a small weatheproof subpanel. Add the proper sized 2 pole breaker for the A/C and then add a 20A single pole breaker for your outside outlet. The subpanel will act as a disconnect for the A/C so you will no longer need the disconnect.

-rick

[hj]

VERY few air compressors have a neutral wire, since they do not have any 110/120 volt components. In addition, the circuit breaker is primarily to protect the wires, NOT just the appliance, so any wires connected to that circuit would have to be rated for 50 amps, which is a little large for a duplex receptacle.

[jeffeverde]

Ok, i think there is some confusion about the situation.

It is my understanding that what Jeff has is:

120' of 6/3 with ground that runs out to a fused disconnect box. From this box he has wired up the A/C unit. If this is true, there is an unused neutral wire in the circuit that could be used to make the 110v circuit. . . .

Correct

Remove your outdoor A/C disconnect and replace it with a small weatheproof subpanel. Add the proper sized 2 pole breaker for the A/C and then add a 20A single pole breaker for your outside outlet. The subpanel will act as a disconnect for the A/C so you will no longer need the disconnect.

-rick

Thanks for your input, that's what I was thinking.

[jar546]

I've got a 230v/50A circuit supplying the A/C compressor and the compressor only requries 35A, so overloading the 50A circuit isn't an issue.

Ahh,...yes, yes it is an issue.

What is the motor FLA, FLC, HP & Service Factor

[codeone]

I've got a 230v/50A circuit supplying the A/C compressor and the compressor only requries 35A, so overloading the 50A circuit isn't an issue. The A/C circuit terminates in a fused disconnect box, and then a whip into the unit.

What is the minimum circuit ampacity for you a/c?
What is the max breaker size for your a/c?

These facts are needed to do the calculation you need.

[codeone]

I've got a 230v/50A circuit supplying the A/C compressor and the compressor only requries 35A, so overloading the 50A circuit isn't an issue. The A/C circuit terminates in a fused disconnect box, and then a whip into the unit.

The issue is if your minimum circuit ampacity is 35A you haved to multiply 35 x 125% to come up with your calculated load for the circuit. This is for start up current.

35 x 125% = 43.75 or 44A
50A - 44A = 6A
Dont have as much extra as you thought!

Now if the 35A is you max breaker size you might be ok.
Give us some more info please.