[AngliaBob]

I just purchased a compressor with a 15amp 240 v motor.
I have 2 separate 110v circuits close to the compressor.
Can I use the hot leg from each of these circuits to supply 220v?
Logically it sounds correct, but I am not an electrician.
Thanks,
Bob

[w8rok]

Hi Bob,
First, I would never want to give advise that might harm or KILL somebody. Electricity is something that you cannot take lightly or it will do just that. With that said I will give you my opinion what I think you should do. You really need to supply your air compressor with 220vac form you breaker box with the recomended 220 volt breaker. This type breaker will work properly if something should happen where the two seperate breakers might not and could cause some damage or personal harm. You never want to take shortcuts or chances when it comes to electricity. Also depending on the distance you have to run the wire you will need at least a number 10 AWG maybe 8 AWG size copper wire or comprable size aluminum wire (the smaller the number the larger the wire). You more than likly have 12 or 14 AWG at your recepticles and that would be too small anyway and would get very hot and could cause damage. If I were you I would consult a local electrician and have him give you a hand or at least show you the SAFEST and best way to take care of your need.
I hope this has helped and I hope that I did not step on your toes with my response... I just think that the safe way is always the best way.

Sincerely,
Rok Hoblitzell

[AngliaBob]

Rok,
Thanks for the info..
I have done quite a bit of electrical work in the past, but this was a new situation, and I was trying to use what was available...
I will run a new circuit for the compressor,(It will be a PITA)..
Thanks
Bob

[oldred]

Good move running the 220 volt line because even if this can be made to work I can see several possible issues here, especially if you manage to trip just one breaker and not the other which I think might happen.

[bluesman2333]

You are required by the NEC (National Electrical Code) to run a circuit from a two pole circuit breaker that serves only that motor load. You will run then, two hots and a ground. Depending on your local codes, this can be in NMC, MC or raceway AKA flex or pipe.

Depending on the circuit length, this might be in #10 or #8 depending on the distance and RLA, running load amps. THe back of the NEC has tables for calculating voltage drop, but I'm sure there are on-line calculators for you to figure this out.

DO NO SKIMP ON THE WIRE SIZE. This will cause a fire.

[chas350]

Also I believe aluminum wire (mentioned above) is no longer is accepted by code. be sure to use copper. 15 amps is not much but the distance you are pushing it is important in determining the guage. You would deff. want to use a dedicated 2 pole circuit.
have fun, keep it safe

[bluesman2333]

There is nothing prohibiting one from using aluminum wire but it doesn't make sense for the do-it-yourselfer due to engineering and installation issues. HD, Lowes and other home centers usually only sell copper wire in the smaller sizes anyway.

[AngliaBob]

Thanks to all for your input...

I have run a new circuit , 2 hot 1 ground #8 and a 30amp double breaker.
Total run was 45 feet from the box.
I will finish it up tomorrow...

Thanks again
AngliaBob

[w8rok]

Sounds like you did a good job Bob. You wont be sorry.

Rok H

[Rambo_The_Dog]

Originally Posted by AngliaBob

Thanks to all for your input...

I have run a new circuit , 2 hot 1 ground #8 and a 30amp double breaker.
Total run was 45 feet from the box.
I will finish it up tomorrow...

Thanks again
AngliaBob

Good job - you won't be sorry you took the extra time.

I couldn't believe the cost of wiring when I did mine 1.5 years ago - how bad was this run of wire?

[Cape Cod Bob]

U can get some deals on ebay on wire or craigs list. Ends of rolls etc.

[Rambo_The_Dog]

Originally Posted by Cape Cod Bob

U can get some deals on ebay on wire or craigs list. Ends of rolls etc.

Good ideas for alternative sources - if I can plan ahead...mostly on a project I tend to need it now!

[scotzz]

Originally Posted by bluesman2333

You are required by the NEC (National Electrical Code) to run a circuit from a two pole circuit breaker that serves only that motor load. You will run then, two hots and a ground. Depending on your local codes, this can be in NMC, MC or raceway AKA flex or pipe.

Depending on the circuit length, this might be in #10 or #8 depending on the distance and RLA, running load amps. THe back of the NEC has tables for calculating voltage drop, but I'm sure there are on-line calculators for you to figure this out.

DO NO SKIMP ON THE WIRE SIZE. This will cause a fire.

How can you determine if you have the circuit wired correctly? For 115v you can simply plug in a circuit tester and it will tell if the polarity and grounding is correct. Is there any such device for 230v? If not then how can you check?

[bluesman2333]

Any good voltage tester or volt meter will do, as long as it is fairly accurate and can read 300 volts.

A 230 volt outlet in a residence most commonly will have three holes. One will be radically different from the other two and will be the ground. The other two will read 220 volts between them and 115 volts to ground.

The outlet size and configuration will depend on the load you are putting on it and the duty, ie you can get a light residential type outlet all the way to pin and sleeve types for industrial use.

Note that you don't necessarily need an outlet as many things can be direct wired and direct wiring is desirable with motor loads on equipment that remains stationary like air compressors and welders at a work station.

[scotzz]

When either wiring for a compressor or welder, do you need 4 wires with a neutral or is 3 wires OK (3rd being ground)?