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Old 11-13-2008, 07:45 PM   #1
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


I'm in the process of rewiring my garage. (Basically, I'm at the rough-in stage, but it will go quickly after I get the boxes mounted and the cables stapled.)

Main question: I'm using all 12 ga wiring so that I can run 20 amp breakers. I'm also using metal boxes, which obviously need to be grounded. I bought a baggie of pre-made ground pigtails for that purpose, but it turns out they're 14 ga. Is it acceptable for the ground connection on the metal box to be 14 ga, or should I scrap those and use 12 ga exclusively?

Second question: I got a good deal on some ceiling boxes for the lighting (planning to use 4 of them for some basic ceramic light fixtures), but they don't have any mounting brackets built in. Can I just mount them directly to the underside of the ceiling joists with wood screws, or could that become a fire hazard? (I'll be using screw-in CFLs, but you never know if some future homeowner or renter might put 150-200 watt incandescents in there, so I'm a little concerned about the potential heat.)

EDIT--Third Quick Question: can I double up the NM cable under the staples (each staple securing two cables), or should I run two cables side-by-side?

Thanks!


Last edited by thegonagle; 11-13-2008 at 07:59 PM. Reason: Third question?
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Old 11-13-2008, 08:25 PM   #2
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


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a. Is it acceptable for the ground connection on the metal box to be 14 ga
You can't use a 14 gauge ground with 12 gauge wires, unless the breaker is 15 amps.



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Third Quick Question: can I double up the NM cable under the staples (each staple securing two cables), or should I run two cables side-by-side?
You aren't supposed to. It's a pretty minor issue though. If you want to save time get the extra wide staples and you can do two at once side by side.

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Old 11-13-2008, 08:27 PM   #3
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


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Third Quick Question: can I double up the NM cable under the staples (each staple securing two cables), or should I run two cables side-by-side?
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You aren't supposed to.

Why not? My staples are listed for such use.
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Old 11-13-2008, 08:27 PM   #4
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


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Why not? My staples are listed for such use.
I read somewhere you weren't supposed to stack NM under staples. Maybe what I read was wrong.
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Old 11-13-2008, 08:28 PM   #5
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


Most staples are Chris, not just yours.
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Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC. If you're on the '14 already I feel sorry for you.
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Old 11-13-2008, 08:29 PM   #6
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


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I read somewhere you weren't supposed to stack NM under staples. Maybe what I read was wrong.

Dont know what you read, but Briscon staples allow multiple wires under one staple. You cannot staple wires on edge, but thats the only nec issue.
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Old 11-13-2008, 08:29 PM   #7
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


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I read somewhere ...........
Famous last words.
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Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC. If you're on the '14 already I feel sorry for you.
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Old 11-13-2008, 08:30 PM   #8
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


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Famous last words.
You got that right. I defer to you guys.
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Old 11-13-2008, 08:30 PM   #9
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


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Most staples are Chris, not just yours.

I'm sure, but not all staples are created equal.
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Old 11-13-2008, 08:32 PM   #10
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


Oh I know. I was just bustin'.

I have seen some rated for three cables.
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Sometimes I feel like if I answer any more questions it is like someone trying to climb over a fence to jump off a bridge and me giving them a boost.
Answers based on the 2008 & 2011 NEC. If you're on the '14 already I feel sorry for you.
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Old 11-13-2008, 08:33 PM   #11
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


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Oh I know. I was just bustin'.

I have seen some rated for three cables.

I know you were.
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Old 11-13-2008, 08:34 PM   #12
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


You all should answer his other question because I'm kind of curious too. I think it would be ok but I wasn't sure enough to say that. (The one about the light boxes)
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Old 11-13-2008, 08:38 PM   #13
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


Well, you need to use 12 awg, all metal boxes need to be bonded to the ground, you can stack romex with the connectors if they are rated for such.
You NEED an electrical box for the lights, or do you mean installing the box to the bottom of the joist? I dont think there is anything wrong with that.
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Old 11-13-2008, 08:43 PM   #14
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


OK, I'll scrap the 14 ga. pigtails, and I'll double check that my staples are approved for two cables before I try that trick. (I got the idea to double up the cables because the previous homeowner, supposedly a general contractor, did that in several places when he re-wired the main house, but I just wanted to be sure it's OK.)

What about the ceiling boxes? (I believe they're called octagon boxes; indeed they're approximately octagonal in shape.) I can just shoot 'em up there to the bottom of the joists with wood screws, right?

Note: it's an unfinished, detached garage, and I have no plans to drywall, so having them stick out too far from the bottom of the joist is no concern to me.

(EDIT: Of course I'm using boxes for the light fixtures! Sorry, I'm not always the clearest writer.)

Last edited by thegonagle; 11-13-2008 at 08:46 PM.
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Old 11-13-2008, 08:57 PM   #15
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Installing 20 amp circuits in metal boxes, is 14 ga OK for ground pigtails?


I often see 14 for gnd pigtails. Not code compliant though. It makes the recep a bit more manageable. Actually, one inspector recently OK'd it.


I often put two/three cables under a staple. After several thousand staples, it's never been an issue.

Install the ceiling boxes on the side of the joist so your fixture will mount flush to the bottoms of the joists.

Can't use NM cable in unfinished garages here.

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