Wiring for 220v compressor

[kerwinq]

I am running wire for a 22ov compressor using 10/2 wire. I thought I could use this and not run an extra wire as a common ground but just use the ground in the wire. I was talking to a buddy and he thought I needed to have both a ground and a common ground, is this needed or am I good to use the 3 wires that I have in the 10/2? I am using a 3 prong dryer plug and the motor is 15 amp, was going to use a 30 amp breaker.

Another question, will I harm anything by running another 220 plug off the same breaker or should I use a dedicated breaker for each one?

Thanks, Kerwin

 

[ddawg16]

As long as the compressor is strictly 220 and does not need a common....you are fine. Remember, the ground will go only to ground....

I'm also going to assume the switch on the compessor is designed for 220. In other words, the contactor coil is a 220v coil. If it is 110, then you will also need to run a common over there.

You can run another plug off the same breaker.....but....you want to make sure that both devices don't operate at the same time. I'm assuming you want a plug for the welder?

 

[kerwinq]

The compressor is set up for 220v only as it is a Craftsman 60 gal. The compressor was used when I got it and already had the plug wired in but the motor on it is for 220v. The additional plug would be used if I got a larger welder in the future, just didn't want to have to run wire again later if I didn't have to

 

[rinny_tin_tin]

I am running wire for a 22ov compressor using 10/2 wire. I thought I could use this and not run an extra wire as a common ground but just use the ground in the wire. I was talking to a buddy and he thought I needed to have both a ground and a common ground, is this needed or am I good to use the 3 wires that I have in the 10/2? I am using a 3 prong dryer plug and the motor is 15 amp, was going to use a 30 amp breaker.

Another question, will I harm anything by running another 220 plug off the same breaker or should I use a dedicated breaker for each one?

Thanks, Kerwin

You only need a total of three conductors - 2 for the 220, and the third for gnd. You do not need a neutral.

 

[brownbagg]

a 220 is really (2) 110 off phase if you test one wire against ground it be 110, if you test the two 110 hots it will be 220, so you need 110,110, ground. The 110 are off phase dont forget. off the compressor plug no big deal but off the circuit breaker box you got to understand the (2) 110

 

[sberry]

Its really a 240 system.

 

[Torque1st]

Its really a 240 system.

Except at my house it would be a 250V system, voltage varies... I am not even sure what we should call a "nominal" voltage anymore. I think whether we call it 110, 115, 117, 120 or 220, 230, 240, etc the nomenclature is understood. Where people really get confused is the single phase -vs- 3 phase systems.

 

[nadogail]

The compressor is set up for 220v only as it is a Craftsman 60 gal. The compressor was used when I got it and already had the plug wired in but the motor on it is for 220v. The additional plug would be used if I got a larger welder in the future, just didn't want to have to run wire again later if I didn't have to

My advice is to run two hots, a neutral and a ground for your compressor.

Are you trying to only do the minimum or are you seriously planning to
add a "bigger welder"? Trying to do a wiring job "on the cheap" is a recipe for regret. I have been there and done that.

Bigger welders can use some serious power. My little Hobart Stickmate is connected to a 50 Amp breaker by way of AWG 8 wire. A bigger welder, used to capacity will need bigger wire and circuit breaker.

 

[tfi racing]

Interesting.I'd like to see a welder or compressor that requires a neutral,let us know when you find one.

 

[ket-tek]

I think whether we call it 110, 115, 117, 120 or 220, 230, 240, etc the nomenclature is understood. Where people really get confused is the single phase -vs- 3 phase systems.

don't forget 208v also

 

[nadogail]

Interesting.I'd like to see a welder or compressor that requires a neutral,let us know when you find one.

The Neutral is not required by either my welder or table saw, but it is there for future, yet to be determined, needs.

 

[Torque1st]

Interesting.I'd like to see a welder or compressor that requires a neutral,let us know when you find one.

My compressor requires a neutral because of the controls. I suppose I could rewire it and put in a transformer for the control voltage. It has various control modes with head unloaders etc. I purchased it used from a local company.

 

[Torque1st]

don't forget 208v also

That 208V and 277V stuff is 3 phase industrial power... We can add a whole lot of different voltages and types used if you want to go there.

 

[buening]

I second the advice to run the neutral wire and put a wire nut on the end of it, for the possibility of future changes requiring a neutral. I ran my 6ga wire for my 240V compressor and it has two hots, a capped neutral, and the ground wire. I ran mine through conduit and can't imagine having to pull the wire back out and re-running it for a neutral. I believe there are some 240V compressors with a 120V magnetic starter box, which would require both two 120V legs, one 120V leg and one neutral, as well as a ground. I could be wrong though

 

[W-Cummins]

That 208V and 277V stuff is 3 phase industrial power... We can add a whole lot of different voltages and types used if you want to go there.

There are a lot of apartments and condominiums that run 208V as the hot to hot voltage. It's getting more common all the time. The 277V (hot to grounded conductor) is not normally used in dwelling units, but some high rise office building use it for lighting.

I have and use both in my shop. In fact I don't have any 240V at all....

William...

 

[Torque1st]

There are a lot of apartments and condominiums that run 208V as the hot to hot voltage. It's getting more common all the time. The 277V (hot to grounded conductor) is not normally used in dwelling units, but some high rise office building use it for lighting.

I have and use both in my shop. In fact I don't have any 240V at all....

William...

That 208 is 3-phase, each leg is ~120V to Neutral. It is used in light industrial areas and as you mention some Condo's etc. 277 is also 3 phase.

 

[nadogail]

That 208 is 3-phase, each leg is ~120V to Neutral. It is used in light industrial areas and as you mention some Condo's etc. 277 is also 3 phase.

277 is the voltage measured from a wye or star connected 480 volt leg and neutral. A very common voltage for commercial lighting.

 

[Torque1st]

277 is the voltage measured from a wye or star connected 480 volt leg and neutral. A very common voltage for commercial lighting.

Exactly! 3 phase voltages and discussions are far afield from the OP's question tho.

For 3 phase questions etc go to:
http://www.mikeholt.com/
http://www.cnczone.com/forums/forumdisplay.php?f=273
http://www.practicalmachinist.com/vb/forumdisplay.php?f=11