Garage sub-panel

Reply

  #1  
Old 09-08-12, 12:44 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Garage sub-panel

I am planning on installing a subpanel in my garage prior to wiring and finishing it. I bought a Siemens panel with a 100amp main breaker to use as the sub, but how do I feed it? I have been told to use a 6-4 wire (which I assume is a 6-3 with a ground), and I can find the 6-3 w/ground locally. Does that sound right? What size breaker should I run it off of in my main panel, 60amp?

Also, my basement is unfinished, so running the cable won't be a huge undertaking, it's about 65' to the point in the garage where I want the panel. Does a wire this size need to be put in conduit if the entirety of the run is indoors?

Thanks.
 
Sponsored Links
  #2  
Old 09-08-12, 01:24 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
how do I feed it? I have been told to use a 6-4 wire (which I assume is a 6-3 with a ground), and I can find the 6-3 w/ground locally. Does that sound right? What size breaker should I run it off of in my main panel, 60amp?
Breakers are sized to protect the wire they're supplying. If you choose to supply your subpanel with 6AWG conductors, then you need to protect those with a 2-pole 60A circuit breaker. 6-4 is not what you need (that's four 6AWG current-carrying conductors). 6-3/G is what you need. The ground can be smaller that 6AWG.

Does a wire this size need to be put in conduit if the entirety of the run is indoors?
Cables are made to be run on their own. Individual conductors are run in conduit.
 
  #3  
Old 09-08-12, 01:35 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
Just to add a bit the 100 amp breaker in the subpanel is only used as a disconnect so while you can use any feed size up to 100 amps a smaller feed is fine. As Nash stated 60 amps is fine. Maybe even less depending on your loads. You will also need to add a bonded ground bar which is usually sold separate to the subpanel and check the neutral is isolated. You will need in addition to the EGC (equipment grounding conductor) from the main panel connected to the ground bar an eight foot ground rod and wire to the ground bar.
 
  #4  
Old 09-08-12, 02:43 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Forgive my dumbness here. So I can use the 6-3 w/ground and 60A breaker to feed this? And you lost me on the ground bar, do you mean one I one have to drive into the ground outside? Or can I ground the new panel off of my main?

I can't upload pics from my tablet, but the new sub does have a ground bar installed in it.

Here is the panel I bought.

Shop Siemens 20-Circuit 10-Space 100-Amp All-in-One/Combination Main Breaker Load Center Value Pack at Lowes.com

Thanks for all your help.
 
  #5  
Old 09-08-12, 03:39 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
Ground bar goes in the panel. Ground rod goes in the ground. If the panel has only one bar and it is on insulators that is the neutral. A ground bar has no insulators and is screwed directly to the panel.They are normally not included.

You are really going about asking this wrong. First tell us what loads you have in the garage. Are there any 240 volt loads? If no 240 volt loads you may not need a subpanel. Even if you have a 240 load you may be okay with a thirty amp feed and smaller wires.

 

Last edited by ray2047; 09-08-12 at 04:15 PM.
  #6  
Old 09-08-12, 04:33 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Fridge, freezer, power tools, table saw, air compressor, etc. I like the convenience of having the panel in the garage as its currently unfinished and I have delusions of grandeur on what I will do with as I finish it.
 
  #7  
Old 09-08-12, 06:52 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
So I can use the 6-3 w/ground and 60A breaker to feed this?
Yes.

And you lost me on the ground bar, do you mean one I one have to drive into the ground outside? Or can I ground the new panel off of my main?
It sounds like your garage is attached to the house. If so, all you need is to have an isolated neutral bar and a bonded ground both inside your subpanel, with the neutrals and grounds separated to each.

If your garage is a separate, detached structure, then you need the isolated neutral, the bonded ground, and a driven ground rod bonded to the subpanel. That is, you need a grounding electrode conductor for your subpanel that is independent of the GEC for your main panel.

Forgive my dumbness here.
Understand, yes. None of us was born knowing any of this. Educate, yes. That's how we grow. Forgive, no. Overlooking ignorance about proper methods of providing for the safe use of electricity would be equivalent to watching someone have a car wreck that you could have prevented.

But I don't think you really meant that. Because I don't think you'd be here asking these questions if you did want us to "forgive your dumbness."
 
  #8  
Old 09-08-12, 07:37 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
Great minds sometimes take divergent paths. Nash reads your post and thinks attached. I see "65 feet" and think it is detached. Before we go further we need to know which. So we can both journey forward on the same path. Is this a detached garage?
 
  #9  
Old 09-10-12, 06:20 AM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Garage is attached, shared wall with the house is the only finished wall in the garage currently, and will be where the sub-panel goes. Then i planned on stubbing out a PVC pipe from the top of the panel out to above the rafters so i can insulate/rock the ceiling.

Here is the inside of the subpanel i bought, if that helps in any way.

Thanks.

Name:  photo.jpg
Views: 13907
Size:  32.4 KB
 
  #10  
Old 09-10-12, 09:33 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
That may be a ground bar at the very bottom of the picture and the holes where another one goes if needed. I can't see it clearly enough. The plastic bag on the right middle contains the bonding screw for the neutral bars on the left. It is NOT used in a subpanel.
 
  #11  
Old 09-10-12, 10:24 AM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Perfect. Thank you guys for all your help. I will reply back with pictures once i have the cable run, but before having the inspection and turning it up.

Joel
 
  #12  
Old 09-10-12, 11:11 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
Be sure to show us a little further down so the ground bar shows clearly.
 
  #13  
Old 09-11-12, 12:04 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
One more thought on this before I pull the trigger. Is it OK to run a 2" (or whatever size) PVC conduit out the top of the subpanel and feed my 12-2 wires for circuits down it into the box? Does having that conduit alleviate the 12" staple rule for incoming wires?

my plan is to stub that PVC out above the rafters so i can still run lines to the box after I put the sheetrock back up on the wall holding the subpanel.

thanks,
Joel
 
  #14  
Old 09-11-12, 01:14 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
Is it OK to run a 2" (or whatever size) PVC conduit out the top of the subpanel and feed my 12-2 wires for circuits down it into the box?
Not code for a very long time though that is the way it use to be done. Each cable must go through a cable clamp (AKA cable connector). Most cable clamps are rated for two #12 cables.
 
  #15  
Old 09-13-12, 03:13 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
So I can't run multiple cables down 1 large conduit into the box? Another thing, is it OK for the box itself to be touching fiberglass insulation? I plan on installing it in the shared wall into the house, which is insulated and sheetrocked already.

Ive got my (surprisingly expensive) 6-3 cable and am ready to roll with this project finally.

Thanks.
 
  #16  
Old 09-13-12, 03:15 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
Insulation is not a problem.
 
  #17  
Old 09-13-12, 05:57 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,361
The conduit out of the top of the panel is only allowed if the panel is surface mounted. There are other stipulations also but the surface mounting is the biggest item.
 
  #18  
Old 09-13-12, 06:33 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Turns out there is osb behind the the Sheetrock. Looks like I'll be surface mounting on the osb after all. So conduit it is.
 
  #19  
Old 09-13-12, 08:23 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
So conduit it is.
Make that "conduits." No more than two circuits (cables) in any one conduit, and that should be a 3/4".
 
  #20  
Old 09-16-12, 07:00 AM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Nothing but issues so far on this project. Next question, since I have to surface mount the panel now, I cant easily relocate the feed to the current GFCI outlet into the new panel.

However, if I remove the 12-2 that feeds the garage outlets from the main panel in the basement, can I feed that 12-2 through the 1" conduit along with the 6-3 into the garage panel?
 
  #21  
Old 09-16-12, 05:25 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Here are the first pics for your review. I don't have the end at the main panel terminated yet, that'll be the last thing I do before having the inspection.

Please let me know if this looks OK.

Thanks.

Name:  2012-09-16_18-08-55_457.jpg
Views: 13165
Size:  17.3 KBName:  2012-09-16_18-09-03_12.jpg
Views: 13099
Size:  9.9 KBName:  2012-09-16_18-09-15_982.jpg
Views: 15061
Size:  20.6 KB
 
Attached Images  
  #22  
Old 09-16-12, 05:55 PM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
The interior looks pretty good. I would shorten the insulated conductors enough to pull them off the panel box. A picture from far enough away to show the panel on the wall with the feed coming into it would be helpful.

One question: Is the ground bar bonded to the cabinet? Have you checked for continuity between them?
 
  #23  
Old 09-16-12, 06:03 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
The ground bar is attached directly to the back of the cabinet, there is no insulator between the bar and the metal back. Is that what you meant? I have not checked the continuity between them, I don't have teh tools for that yet.

Here is a pic of the conduit that feeds it from the basement. (Yes, the conduit is crooked, but the panel is not)


Name:  2012-09-16_18-09-50_128.jpg
Views: 19082
Size:  14.3 KB
 
  #24  
Old 09-18-12, 01:09 AM
Member
Join Date: Jul 2012
Location: USA
Posts: 54
Do the ground and neutral bars have to have separate ground rods going into ground, or can they share the same rod (1 rod)? Im thinking two rods.
 
  #25  
Old 09-18-12, 02:47 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,361
A panel in an attached building does not require additional rods or electrodes.
 
  #26  
Old 09-18-12, 07:37 AM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
The ground bar is attached directly to the back of the cabinet, there is no insulator between the bar and the metal back. Is that what you meant?
No. That's visible in the picture. But I also noticed that the paint on the cabinet appears to still be in place under the ground bar.

If so, the mounting screws for the ground bar are providing all of the bonding. Since you say you don't have a tool to check for continuity (no multimeter?), you almost certainly don't have a tool to check the resistance between the bar and the cabinet. For caution, then, I would unmount the ground bar, remove the paint from the area behind it, and remount it against the bare metal.
 
  #27  
Old 09-27-12, 06:21 AM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Sorry, i missed your last post about the ground bar. I will remove it and make sure it has good contact with the bare metal of the box. I finished wiring in on both sides last night, shortened the wires in the subpanel as had been suggested. Here are the pics. I'll be calling for inspection today hopefully.

Thanks again for everybody's help on this.

Name:  IMG_0014.jpg
Views: 38585
Size:  33.7 KBName:  IMG_0015.jpg
Views: 32118
Size:  31.8 KBName:  IMG_0016.jpg
Views: 14742
Size:  45.6 KBName:  IMG_0017.jpg
Views: 13181
Size:  33.6 KBName:  IMG_0018.jpg
Views: 13465
Size:  49.9 KBName:  IMG_0019.jpg
Views: 13007
Size:  44.4 KB
 
  #28  
Old 09-27-12, 06:27 AM
Nashkat1's Avatar
Member
Join Date: Mar 2012
Location: USA
Posts: 8,470
I'll be calling for inspection today hopefully.
It looks ready for inspection.
 
  #29  
Old 09-27-12, 04:29 PM
Member
Thread Starter
Join Date: Sep 2012
Posts: 26
Inspection went fine, everything passed and is now hot and working great.

Thanks again to all of you for your help. Basement is next, so I'm sure I'll be back soon.

Thanks,

joel
 
  #30  
Old 09-27-12, 05:55 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
Good job. Thanks for letting us know. Come on back any time.
 
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
'