Multiple branch circuits in one EMT run.

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Salvador Santos

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Bahrain
Since I started working I had the notion that branch circuit cables should be run separatey in each raceway (in this case EMT). I have always thought that this is as per Electrical codes but I'm having a hard time finding a paragraph about it in NEC 2008.

One of our subcontractors plans to separate circuit lines in one EMT provided that he will just adjust the size to attain the proper conduit fill percentage. I declined his proposal. But now I'm in a dilemma since I cannot back up my decision with the statement coming from the NEC.:happysad:

Really need your help about this. Thanks!
 
PetrosA

PetrosA

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Salvador Santos said:
Since I started working I had the notion that branch circuit cables should be run separatey in each raceway (in this case EMT). I have always thought that this is as per Electrical codes but I'm having a hard time finding a paragraph about it in NEC 2008.

One of our subcontractors plans to separate circuit lines in one EMT provided that he will just adjust the size to attain the proper conduit fill percentage. I declined his proposal. But now I'm in a dilemma since I cannot back up my decision with the statement coming from the NEC.:happysad:

Really need your help about this. Thanks!
Click to expand...

You can run lots of circuits in a raceway, provided you don't violate the fill requirements and do derate the conductors.
 
ActionDave

ActionDave

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Salvador Santos said:
Since I started working I had the notion that branch circuit cables should be run separatey in each raceway (in this case EMT). I have always thought that this is as per Electrical codes but I'm having a hard time finding a paragraph about it in NEC 2008....
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You won't find it in the 2008 NEC or any newer or older editions.

One of the main advantages of EMT is that you can get a lot of branch circuits out of a panel in one conduit and branch out from remote j-boxes.
 
Ponchik

Ponchik

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Also, if you run MWBC make sure the two or three hots with the sharing neutral are tied together to identify them as a family.

edit to add: keep in mind regardless of the size of the conduit you also have to derate the conductor ampacity.
 
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480sparky

480sparky

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Iowegia
The only limit to how many circuits you can put into EMT is how many you can put into 4" EMT, as that's the largest size made.
 
infinity

infinity

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Dr Mantis Toboggan said:
I've used 6"
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Maybe for beverage lines but the NEC limits EMT to 4".

358.20 Size.
(A) Minimum. EMT smaller than metric designator 16
(trade size1⁄2) shall not be used.
Exception: For enclosing the leads of motors as permitted
in 430.245(B).
(B) Maximum. The maximum size of EMT shall be met-
ric designator 103 (trade size 4).
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Dr Mantis Toboggan

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Location
US
infinity said:
Maybe for beverage lines but the NEC limits EMT to 4".
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No, it was electric.

I wasn't aware that it was against code, I was only an apprentice at the time, we ran 6" EMT from a large UPS to a large enclosure in a hospital. I wasn't around to see exactly what was pulled into it.
 
Ponchik

Ponchik

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Dr Mantis Toboggan said:
Yes, they do, Bob.
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Assuming they used to make 6" but now they don't. Unless you know of a manufacturer that you can post here.

I checked two different manufacturer and one manufacturer that makes just prebends and all three listed to 4" only.
 
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Dr Mantis Toboggan

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US
edward said:
Assuming they used to make 6" but now they don't. Unless you know of a manufacturer that you can post here.

I checked two different manufacturer and one manufacturer that makes just prebends and all three listed to 4" only.
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Maybe, but there is too many to check individually. We got the 6" EMT and associated fittings from Cooper Electrical Supply in NJ, if anyone would like to call them to see if they sell or used to sell 6" EMT, by my guest.
 
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