Wirenut, twisting and box fill

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Old 01-25-10, 09:09 AM
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Wirenut, twisting and box fill

I suddenly realized that in about half of pigtails I close with wirenuts, I twisted pigtails counterclockwise. The wirenuts are twisted on clockwise. So, CCW-twisted pigtails may become loose from twisting the wirenut on, while CW-twisted pigtails are fine, and probably just twist tighter from twisting on a wirenut.

I understand that most wirenuts don't even require twisting conductors at all. But is there anything in NEC about the direction of the twist, if you do twist the conductors together? Would the inspector become suspicious of incorrectly twisted conductors? Is it cheaper for me to redo everything, or try to pass the inspection as is?

Also, somewhat unrelated: in one 34 cu.in. heavy duty 2-gang electrical box (rated for 17 conductors), I used oversized wirenuts to fit like 7 conductors together (including 2 jumpers to the switches). NEC states that wirenuts and jumpers don't count for box fill calculations, but maybe oversized wirenuts count?

Also, yet another thing: I have a pigtail of ground (bare copper) conductors, which I just "twisted on" the new grounding jumper, and it looks messy (or at least not neatly twisted together, but kinda twisted together). Do inspectors often have problems with that? Is it even necessary to use a wirenut on grounding wires if they're tightly twisted together? Who cares?
 
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Old 01-25-10, 09:39 AM
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If it were me I would redo all the CCW splices. Loose connections can cause problems including potential fires.

The larger wirenuts should not be an issue.

Yes the grounding conductors need either a crimp or another method like a wire nut to keep them secure. You can buy green wire nuts just for this purpose that let a tail extend out to ground your devices.
 
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Old 01-26-10, 12:47 PM
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Originally Posted by migdalskiy View Post
But is there anything in NEC about the direction of the twist, if you do twist the conductors together?
The NEC requires all equipment to be installed per manufacturer's instructions. I suspect they probably say to screw them on CW.

Is it cheaper for me to redo everything, or try to pass the inspection as is?
I recommend remaking the connections.

maybe oversized wirenuts count?
They're okay as long as the number of wires is in the list of allowed combinations from the wirenut maker.

Do inspectors often have problems with that? Is it even necessary to use a wirenut on grounding wires if they're tightly twisted together? Who cares?
Yes and yes. Ground wires must all be mechanically connected either by wirenuts, crimps, or similar connectors. Anyone who's interested in a code-compliant installation cares.
 
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Old 01-26-10, 02:01 PM
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Thanks!

Thanks for your replies, they were most useful!
 
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Old 01-27-10, 02:35 PM
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If you made your ground pigtails by leaving one wire long and cutting the rest short, then twisting them together, there is a wirenut made specifically for this. They are green and have a hole at the tip for the longer wire to come through. Ideal calls them Greenies.

 
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Old 01-27-10, 08:55 PM
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Originally Posted by migdalskiy View Post
Also, somewhat unrelated: in one 34 cu.in. heavy duty 2-gang electrical box (rated for 17 conductors)
Partially correct. 34 cu.in would equal 17 "conductor allowances" when using 14AWG conductors only. It doesn't mean you can install 17 conductors plus devices, etc.

Working backwards from some of your info, assuming you have two switches in your two-gang box, and it is a plastic box marked as 34 cu.in, and you are using all 14AWG wire:

(2) switches= 2 allowances each = 4 allowances
All grounds = 1 allowance
Normally, no clamp allowances are required for plastic boxes because mfgs. label the boxes already compensating for clamp fills.

Total = 5 allowances x 2.00 cu.in for 14AWG = 10 cu.in

34 cu.in to start - 10 cu in = 24 cu in left for your 14AWG conductors. This leaves you with room for (12 ea) of your 14AWG conductors entering/leaving the box.

Just an example...
 
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Old 01-28-10, 02:12 AM
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Thanks a lot!

Yes, I know about the fill calculations, but it's great to have them double-checked. I have just 2 allowances left in my box (17 allowances - 2 switches, 2x14-2, 2x14-3 cables, ground, no clamps). Don't all clamps count as 1 conductor, too, like the ground? I'm getting my info from this link.

However I have another question, since I'm getting so many helpful responses After opening a box I noticed that the cables that go down pulled out so that they barely have some sheathing inside the box. It's a violation waiting to happen. I'm using these boxes. They don't require cable clamps (or so I was told), and I couldn't find any that fit. All clamps I ever saw were round, and this box has all square knockouts (but one in the back). How do I secure the cable so that it doesn't slide out of this box? The only way I can think of is to somehow get behind the drywall and secure the cables there, if they have enough length. But I'm puzzled at how people secure cables in such old work boxes that have no clamps? Or do they have clamps? Do the knockouts serve as clamps? The knockouts don't look secure at all.

Thanks you all for your helpful responses!
 
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Old 01-28-10, 09:39 AM
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Originally Posted by migdalskiy View Post
Don't all clamps count as 1 conductor, too, like the ground?
Yes, but you do not need to count clamps that are molded into the box.

They don't require cable clamps (or so I was told), and I couldn't find any that fit. All clamps I ever saw were round, and this box has all square knockouts (but one in the back).
The openings in the back are the clamps. Only one side of the square breaks loose to open up a slit in the box. Push the cable through the slit, and the remaining plastic piece should hold the cable. The angle of the plastic piece causes it to grip harder if the cable is pulled out.
 
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