switched Compressor

[gmhill33]

What all do I need to run a switch (light switch) to my air compressor. I have the wire for the air compressor ran to the outlet and I have a piece of 12-2 ran from the compressor outlet to another box for the switch. What else will I need (will I need another wire)?

The reason for the switch is I am having the compressor outside the building.

Thanks,
Gary

 

[nehog]

Compressor 120 or 240? Is the compressor circuit dedicated or not?

 

[gmhill33]

240 and it is on it's own.

Gary

 

[wanderer]

240 and it is on it's own.

Gary

If it's on 240, you probably have a magnetic starter. You can tap into the wire from the pressure switch (in series) so that the pressure switch and your other switch have to be on in order for the compressor to turn on.

I think that's what you are asking. The other way to do it would be to use power from the light switch to apply power to the coil. Turning the lights on allows power to go to the coil and turn the motor on. Do you have a picture of your starter and the wiring in it?

 

[Falcon67]

For a 220 run, you need a two pole switch. HD/Lowes sell some 20A models that would work for a 3 HP compressor.

 

[mrb]

make sure the switch you use is HP rated for your motor size. Even the 30 amp switches are only rated at 2hp @ 240v. Look at the Leviton MS302 motor starter switch. Its rated at 5hp @ 240v. You can also get it in a nifty box as p/n MS402

 

[Charles (in GA)]

It is doubtful that a compressor that uses 12 gauge wire (you don't specify the amps or hp) will use a magnetic starter.

As 67Falcon noted you can get double pole flip switches (like like light switches) in 20amp and you can also get them in 30 amp. Make sure they say that they are "motor rated" and specify the max hp of motor, most this size do.

Run your two hots thru this switch and make sure the compressor is not running when you switch it off (switching a compressor off before it shuts off on its own will leave pressure on the head and it will refuse to start next time, acting like it is locked up, and trip the breaker)

 

[MrMark]

What all do I need to run a switch (light switch) to my air compressor. I have the wire for the air compressor ran to the outlet and I have a piece of 12-2 ran from the compressor outlet to another box for the switch. What else will I need (will I need another wire)?

The reason for the switch is I am having the compressor outside the building.

Thanks,
Gary

It's "have run", not "have ran". Run is the correct past participle. I never do this, but the incorrect usage is so rampant in this section, and this forum in general, that I thought I would point this out. You would not believe how many people I hear say, "I have ran."

 

[gmhill33]

For a 220 run, you need a two pole switch. HD/Lowes sell some 20A models that would work for a 3 HP compressor.

I have a 3 1/2 hp 80 gallon compressor.

Gary

 

[gmhill33]

It is doubtful that a compressor that uses 12 gauge wire (you don't specify the amps or hp) will use a magnetic starter.

As 67Falcon noted you can get double pole flip switches (like like light switches) in 20amp and you can also get them in 30 amp. Make sure they say that they are "motor rated" and specify the max hp of motor, most this size do.

Run your two hots thru this switch and make sure the compressor is not running when you switch it off (switching a compressor off before it shuts off on its own will leave pressure on the head and it will refuse to start next time, acting like it is locked up, and trip the breaker)

I am using 10 10-3 I think for the compressor to the breaker. From where the compressor plugs into the wall I have a 12-2 wire running from there over to the light switch.


Gary

 

[Falcon67]

This is what I have next to my compressor:
http://grizzly.com/products/h8238

 

[gmhill33]

This is what I have next to my compressor:
http://grizzly.com/products/h8238

Will one of those mount in a regular receptacle box? I wouldn't even mind having a light hocked up to it also so when I leave the light will serve as a reminder to turn it off.

Thanks for the link and info.

Gary

 

[Charles (in GA)]

For 240v you would have to run the two hots and a ground to the switch, and then to the compressor, you cannot interrupt just one leg, it will shut the compressor off, but is dangerous to anyone working on the wiring of the unit. You usually cannot go mixing sizes of wire. What is the amp draw of the compressor, its on the motor data plate. Does it require a 10 gauge wire?

Charles

 

[gmhill33]

For 240v you would have to run the two hots and a ground to the switch, and then to the compressor, you cannot interrupt just one leg, it will shut the compressor off, but is dangerous to anyone working on the wiring of the unit. You usually cannot go mixing sizes of wire. What is the amp draw of the compressor, its on the motor data plate. Does it require a 10 gauge wire?

Charles

The guy that hocked it up for me said that the 220 (240) air compressor with a double poll 30 amp breaker required 10 guage wire.

 

[gmhill33]

make sure the switch you use is HP rated for your motor size. Even the 30 amp switches are only rated at 2hp @ 240v. Look at the Leviton MS302 motor starter switch. Its rated at 5hp @ 240v. You can also get it in a nifty box as p/n MS402

What is HP rated?

 

[mrb]

What is HP rated?

horsepower rated. If you are using the switch with a motor, you need to observe the HP rating on it, not just the current. For example a 30 amp 2 pole switch I looked at is only rated for 2hp -same as a 20 amp switch. I havent found a normal lightswitch type switch rated for more than 2 horsepower.

 

[mrb]

The guy that hocked it up for me said that the 220 (240) air compressor with a double poll 30 amp breaker required 10 guage wire.

well you cant run 12/2 from your compressor receptacle to a switch then...

 

[gmhill33]

horsepower rated. If you are using the switch with a motor, you need to observe the HP rating on it, not just the current. For example a 30 amp 2 pole switch I looked at is only rated for 2hp -same as a 20 amp switch. I havent found a normal lightswitch type switch rated for more than 2 horsepower.

Thank you for the clarification sir.

Gary

 

[Falcon67]

Will one of those mount in a regular receptacle box? I wouldn't even mind having a light hocked up to it also so when I leave the light will serve as a reminder to turn it off.

Thanks for the link and info.

Gary

I used a deep metal box to make room for the switch back and wires. It's a bit of a trick to hook #12s to that switch.

 

[haugy]

I think since my breaker box will be right at my door to my shop I will be just hitting the breaker to the compressor as I walk out.