240v garage receptacle wiring - gfi, multiple, etc.

Reply

  #1  
Old 08-10-11, 10:49 AM
Member
Thread Starter
Join Date: May 2009
Location: USA
Posts: 19
240v garage receptacle wiring - gfi, multiple, etc.

I am in the process of wiring my new garage. The 240v outlets have me questioning what the best/correct setup is. I would like two 30a outlets, their main purpose is for an air compressor. There would likely only be one in use at a time, but I want two options of where to place it. Is there anything wrong/more restrictions if they are on the same circuit? What receptacle would be best in this app, 6-30R, 10-30R? Do I need 10-3? I have enough 10-3 UF that I would not have to spend the money to buy NM (spend more $), or I have 10-2 NM.
I also want two 50a receptacles, for future use with a welder likely. I guess I basically have the same questions as above. The plan for this would be easier to put them on separate breakers if that is better. Again, should this be 2 or 3 conductor? do all receptacles have to have neutral an ground to the box requiring 3 conductor?
My other question is do I need GFI protection on these? If so, via GFI breaker? Is that the only way?
Any assistance or other thoughts (constructive) would be appreciated.
JZ
 
Sponsored Links
  #2  
Old 08-10-11, 11:15 AM
Justin Smith's Avatar
Member
Join Date: Dec 2010
Location: Cressona, Pa, USA
Posts: 2,546
What receptacle would be best in this app, 6-30R, 10-30R? Do I need 10-3? I have enough 10-3 UF that I would not have to spend the money to buy NM (spend more $), or I have 10-2 NM
You can use the 6-30 for an air compressor and such. The 10-30 is an obsolete configuration, it is no longer legal and has been replaced by 14-30. The 6-30 can use 10/2g and the 14-30 uses 10/3g. You can use your UF if you wish.

I also want two 50a receptacles, for future use with a welder likely. I guess I basically have the same questions as above. The plan for this would be easier to put them on separate breakers if that is better
I would install a 6-50 for the welder and use either 6/2g or if you want you can run 6/3g and cap the neutral. Why do you want two receptacles?
 
  #3  
Old 08-10-11, 11:24 AM
Group Moderator
Join Date: Oct 2004
Location: WI/MN
Posts: 18,507
You're certainly not going to have the same number of tools needing 240 as 120 so I can see your logic that you could have both 30 amp and 50 amp receptacles on one circuit of each amperage since you're just talking about different locations for the two tools. If you were talking 120 volt circuits, I'd be encouraging more circuits.
 
  #4  
Old 08-10-11, 11:36 AM
Member
Thread Starter
Join Date: May 2009
Location: USA
Posts: 19
Two 50a receptacles would indeed be for two options for equipment locations, very unlikely both would be used at one time. If that scenario changed in the future the one receptacle will be fairly close to the panel and easy to add a second circuit. I was told by another resource some welders with digital display require 4 prong => 6-3 so it may make sense to pull -3 and cap the neutral as stated?
I have quite a few 120v circuits, and totally agree, Mitch.
Thank you for your input.
Jacob
 
  #5  
Old 08-10-11, 12:25 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,288
Originally Posted by jnzaharia View Post
Two 50a receptacles would indeed be for two options for equipment locations, very unlikely both would be used at one time.
Yes you can put multiple receptacles on the same circuit with the understanding that only one is used at any time. Another option would be to get an extension cord for your welder. The manufacturer can give you the distance vs. AWG specs for your particular model.

I was told by another resource some welders with digital display require 4 prong => 6-3 so it may make sense to pull -3 and cap the neutral as stated?
I personally haven't seen a machine like that, but it's certainly possible. In that case you would need a neutral which could be left capped until it's needed. Welder circuits follow different rules than standard circuits, so you almost certainly don't need #6 wire but we would need to know more about the particular machine to know just how small the wire can be. If you don't know which machine you'll have #6 is the most flexible choice. You also have the option of just putting in a 3/4" conduit between the panel and the receptacle box with a pull string inside so that once you get the welder you can pull in the right size and number of wires to match the machine you eventually buy.

If so, via GFI breaker?
GFCI protection is not required on 240V circuits for compressors or welders.
 
  #6  
Old 08-10-11, 02:15 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
Whatever you do, be sure to add enough circuits and plenty of receptacles. Not sure what your main capacity is. We have been building cabinets in my shop this week. Luckily when I built the shop I planned a little ahead, and installed plenty of receptacles along the wall and drop outs from the ceiling, but plenty of circuits, as well, so as not to overload a particular circuit with tools. It has paid off, with three guys doing varied aspects with different tools all spooled up at the same time. I did put my table saw, radial arm, and compressor on 240 circuits to ensure quick spool ups and less drag. I stood back at one time today and noticed we had table saw, radial arm, vacuum system, sanders, planer and router running, while at different times, all day long!
 
  #7  
Old 08-10-11, 07:32 PM
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 4,059
If it were me, I'd run 3/4" or 1" conduit to a couple 4x4 boxes and leave them empty for now. Until you get the shop set up the way you want with the tools you want, you'll always find you wish you put the welder 6' to the left.

When you buy the larger tools, then you can run exactly what's needed to where it's needed. Also, you may find you need a dust collector, 240v tablesaw, etc etc etc. Conduit allows you to do all of that!
 
  #8  
Old 08-10-11, 07:37 PM
Justin Smith's Avatar
Member
Join Date: Dec 2010
Location: Cressona, Pa, USA
Posts: 2,546
Is this an attatched or detatched garage?
 
  #9  
Old 08-11-11, 11:16 AM
Member
Thread Starter
Join Date: May 2009
Location: USA
Posts: 19
This is a detached garage, 100a panel sub from main in house. The conduit is a great idea, though I am going to pass on it at this point. I am going to have plywood sheathing instead of drywall, so removing a couple panels in the future should not be a major problem. I will also have access to the attic to pull wire. Obviously not as nice as conduit, but I would have no issues with running conduit on the surface for needs that may arise later, either. I bought 6-3 so I can just run it and forget about it for now, should cover me for any needs in the foreseeable future. I thank all of you for your input.
JZ
 
  #10  
Old 08-11-11, 11:25 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,288
Thanks for the update, enjoy the new shop.
 
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
'