220V wiring for AC, Welder, Compressor ?

Reply

  #1  
Old 04-10-07, 09:28 AM
Member
Thread Starter
Join Date: Apr 2007
Posts: 5
220V wiring for AC, Welder, Compressor ?

I have a 220V line running through a garage wall to an AC compressor located outside. The prior owner of the house had this installed but definately not to code as the wire is free hanging.

I'm in the process or refinishing the garage and would like to run a 220V for a compressor and welder as well as correct the AC compressor line. The AC is rated at 7amps, the compressor 23amps, the welder hasn't been purchased, but I'm assuming a mig welder at 20-30amp (small home unit). The wire run is 100ft from the breaker box. I'm looking at running a single 8/2 with ground and splicing off a 220V outlet in the garage for the compressor and welder. I plan on using only one piece of equipment at a time (AC, compressor, welder).

One important point, the AC has a fuse with a shutoff switch.

Is 8/2 sufficient? Use regular wire-nuts for splicing the wire? Would there be a reason I should run 8/3 wire instead?

Thanks.
-Boris
 
Sponsored Links
  #2  
Old 04-10-07, 09:55 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,533
The AC should have its own dedicated circuit and disconnect. The welder or compressor should not share the circuit with the AC.

The welder and compressor may be able to share a circuit. Does the compressor have a metal nameplate with the electrical requirements? If so, could you post all of that information?

> Would there be a reason I should run 8/3 wire instead?

No. Neither the compressor nor the welder would require the neutral wire in 8/3.
 
  #3  
Old 04-10-07, 10:01 AM
Member
Thread Starter
Join Date: Apr 2007
Posts: 5
Haven't decided on compressor, so no name plate. But I don't see anything that big. Most units I've eyeballed have 208/230Volts/20 Amps rating (60gal units).

So I should keep the 12/2 AC wiring and add the 8/2 for compressor and welder.

Any thought on just running the 8/2 to a garage subpanel, then branching off the 3 circuits?

Thanks.
-Boris
 
  #4  
Old 04-10-07, 11:12 AM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Unlike most 120-volt circuit, 240-volt circuits are usually individually designed for the equipment that run off them. Sometimes two different pieces of equipment can share the same circuit, but that situation is rare.

You could install a subpanel with three 240-volt breakers in them. Of course you'd want to only have one of the three breakers turned on at any one time. The feeder for the subpanel would be sized to the largest of the three loads. Each piece of equipment will specify the size of wire and breaker that should be used for it.

Although you could use 8/2 for the feeder, I think most people would use 8/3 so that they would have the option of installing a 120-volt breaker if they wanted to.
 
  #5  
Old 04-10-07, 12:19 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,533
> So I should keep the 12/2 AC wiring and add the 8/2 for compressor and
> welder.

Unless there is something very wrong with the AC circuit, yes. You can secure the existing cable with staples and running boards if necessary, but removing the dedicated AC circuit is a step backward in my opinion.

> Any thought on just running the 8/2 to a garage subpanel, then branching
> off the 3 circuits?

This will work, but I suggest that you only branch to the welder and compressor and leave the AC as-is.

If the max OCPD rating on both the welder and compressor is 40A or more, you can just run the 8/2 from a 40A DP breaker to a NEMA 6-50R receptacle and install the matching cords and plugs on the welder and compressor. This way you can simply plug in the machine you want to use at any given time. If both machines will run on a 30A circuit, you can do the same thing but use a 30A DP breaker and a NEMA 6-30R receptacle.
 
  #6  
Old 04-10-07, 02:17 PM
Member
Join Date: Apr 2004
Location: Ontario Canada
Posts: 1,767
Run a separate 8/2 each for the welder and A/C, and a 10/2 for the compressor. You can later attach the appropriate fitting for the air compressor, and to an appropriate breaker in the panel.
 
  #7  
Old 04-10-07, 02:37 PM
Member
Join Date: Mar 2005
Posts: 433
The MIG will need 120 volts, so you will need the netrual.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes