220v wiring in conduit

roofgoofDecember 23, 2009

I will be running a new circuit for an air compressor in my garage. The compressor uses 220 and runs at 22 amps with 41 amps starting draw. Manufacture recommends 50 amps breaker with 10 awg wire. I am going to use 8 awg wire with a disconnect at the air compressor. This system does not require a neutral. I want to run the wire in conduit. I thought that I read somehwere that you can not run only hot wires in conduit without a neutral. Does that sound right? There will be a ground run in the conduit. I have not used conduit before so any help is appreciated. I do know that there are fill levels that will dictate the condit size so I have that part covered.

Thank you for reporting this comment. Undo
Ron Natalie

No, there's no such restriction. If your circuit requires a neutral it must be run with the hot wires (conduit or in cable), similarly with the ground. However, if you don't need the neutral, you don't need to run it ( conduit or not). Just run the three wires you need in the conduit and there should not be a problem. Never hurts to size up either the wire or the conduit. Having a heavier wire may actually be required if you're talking any distance due to voltage drop.

You don't say what kind of conduit you're running, but 3 #8's in sched 80 PVC (about the worst case) will work in 3/4. If you have to go underground to get to the garage make sure the wire is something like THWN that's rated for wet locations. You'll need one green and one color that's not white or green to do this property.

    Bookmark   December 23, 2009 at 10:24AM
Thank you for reporting this comment. Undo
roofgoof

I am planning on using PVC for the conduit. The main panel is in the basement and I will run it from there through the basement, through a wall and into the garage. Total distance is about 60 feet of wire. I dont believe I will need the THWN since it is not wet. Should this be GFI protected?

    Bookmark   December 23, 2009 at 10:33AM
Thank you for reporting this comment. Undo
brickeyee

"Should this be GFI protected?"

Not required and while there appears to be better filtering on newer GFCIs for motor transients nuisance tripping could still be a problem.

    Bookmark   December 23, 2009 at 1:23PM
Thank you for reporting this comment. Undo
Ron Natalie

Sounds like you're not in a wet location. Was unclear if your garage was attached or not. As brick says, GFCI is not required here and probably not a good idea and a 50A 220V one (while available) is going to be pricey (though readily available because this is the common portable spa size).

    Bookmark   December 24, 2009 at 10:18AM
Sign Up to comment
More Discussions
Need help Replacing old dimmer that used only 2 wires in a three way
I need advice as to which wire to connect to which...
txmat
Ceiling fan wiring
I have a new ceiling fan with a light. The fan has...
jjp2121
Motion sensor that doesn't click
I have a motion sensor very much like the picture attached...
drmeow3
Need help with a rocker switch
I need to replace it in our SunHeat radiant room heater....
bold_as_love
How to get garage freezer to work in cold weather
I have a 7-year-old GE refrigerator/freezer in my unheated,...
amyf5
© 2015 Houzz Inc. Houzz® The new way to design your home™