Overlapping bare wire on ground screw

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Knipex Dream

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It is clear as day that overlapping the ground wire over itself under the screw is wrong, but I do like to be knowledgeable and have a solid backing in the rare occurrence that an apprentice will contest the validity their instructions.
I remember even having a print-out with pictures showing to not do so but I don’t know where it is.
What code would prohibit overlapping of wire under a screw, grounding or otherwise?
 
Knipex Dream said:
It is clear as day that overlapping the ground wire over itself under the screw is wrong, but I do like to be knowledgeable and have a solid backing in the rare occurrence that an apprentice will contest the validity their instructions.
I remember even having a print-out with pictures showing to not do so but I don’t know where it is.
What code would prohibit overlapping of wire under a screw, grounding or otherwise?
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110.3(B)

There isn't anything else I am aware of that would address this as a general rule in NEC.
 
The NEC Handbook has some illustrations that suggest wrapping is not permitted. For an EGC I see no problem with it.
 
Don't have the code section handy at the moment, however you cannot use the device to ensure the EGC continuity. Even if it was manufacturer of listed for two ground wires (which none would be, except for Sill-light receptacles, which somehow get around this) you have to pigtail to ground anyway unless it is the last device in the line. You can use one continuous very long ground wire and catch numerous devices in a box, but I have never liked that method of wiring.

If by overlap you mean wrap a wire around the screw more than 360 degrees, basically the same as two wires under there... Cannot overlap like that either
 
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The problem I see is that, for the screw to be tightened, the wire has to be pinched to half its thickness at the overlap, making it prone to breaking. I have taught my son/helper to avoid doing this. I do like to pinch the wire around the screw with pliers to close the loop.
 
JFletcher said:
If by overlap you mean wrap a wire around the screw more than 360 degrees, basically the same as two wires under there... Cannot overlap like that either
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Undecided if it is code violation or not.

Same as two wires under there? Some ways yes, other ways no.
 
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