Return to the Electrical Wiring Forum | Post a Follow-Up

 o
220v wiring in conduit

Posted by roofgoof (My Page) on
Wed, Dec 23, 09 at 10:16

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.


Follow-Up Postings:

 o
RE: 220v wiring in conduit

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.


 o
RE: 220v wiring in conduit

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?


 o
RE: 220v wiring in conduit

"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.


 o
RE: 220v wiring in conduit

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).


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Electrical Wiring Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here