Wires per opening - junction boxes

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Old 03-11-19, 09:29 AM
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Wires per opening - junction boxes

I stumbled across a site online stating that when wiring junction boxes, you should only have one wire per opening? In all of my code research, I had never come across this. Is this really true? If so, I have some re-work to do before my rough-in inspection.
 
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Old 03-11-19, 10:08 AM
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Simple answer is it depends on the box and the clamp. Code allows multiple cables through a single knock-out if the clamp is rated for multiple cables. If you dig down through the manufacturer specs for your clamps it will list the number and sizes of cables that clamp is rated for. If you're using plastic boxes with integral clamps, the box manufacturer will publish specs of number and size of cables allowed. Carlon plastic for example allow only one cable through integral clamps.
 
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Old 03-11-19, 10:26 AM
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Thanks. So on the 1-gang Carlons which have the knockouts instead of the clamps, there shouldn't be any problem with running two through one opening?

I found their FAQ page here. http://www.carlonsales.com/techinfo/...Q-ZipBoxes.pdf

While they don't say specifically that you can put multiple through it, they do say that NEC allows multiple in one opening but only one per clamp. By inference, I would assume that I'm still ok with having run two cables through one opening on the Carlon 1-gangs since they use knockouts?
 
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Old 03-11-19, 01:14 PM
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Thanks. So on the 1-gang Carlons which have the knockouts instead of the clamps, there shouldn't be any problem with running two through one opening?
should not be a problem IF the clamp is rated for two cables.
 
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Old 03-11-19, 05:43 PM
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So on the 1-gang Carlons which have the knockouts instead of the clamps, there shouldn't be any problem with running two through one opening?
No..... you should be fine. Most single gang boxes use knockouts.
It's multigang boxes where clamps are used instead of knockouts.
 
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