Conductors in parallel

[magictolight.com]

Is there any code section which would require paralleled conductors to be installed in separate raceways? I did not see any reason why I could not just up size a conduit for an installation of 2 sets of 4/0 single phase 240 volt conductors, or for that matter 4 sets of conductors going through one conduit say into a service entrance rated transfer switch?

 

[drbond24]

Someone else will have to give you the code reference since I don't have a code book in front of me, but you can't run multiple conductors from the same phase of the same circuit in the same conduit.

 

[StephenSDH]

310.4
250.122(f)

 

[raider1]

Someone else will have to give you the code reference since I don't have a code book in front of me, but you can't run multiple conductors from the same phase of the same circuit in the same conduit.

There is no NEC code section that prohibits running multiple sets of paralleled conductors in the same raceway.

I did not see any reason why I could not just up size a conduit for an installation of 2 sets of 4/0 single phase 240 volt conductors, or for that matter 4 sets of conductors going through one conduit say into a service entrance rated transfer switch?

Yes that would be permissible. Keep in mind that when installing conductors in this manner each conductor of the paralleled set is counted as a current carrying conductor and 310.15(B)(2)(a) would apply. Take a look at 310.4 and specifically 310.4(D).

Chris

 

[magictolight.com]

310.4 Been there but could not find any place that required different raceways. Only requirements if you install them in different raceways. 310.4(c)

 

[StephenSDH]

You also have to run a full size ground for each set. Each conduit must contain sets of (ABC+Full Ground) and not (AAA) in one conduit and (BBB) in another. This is because the electromagnetism cancels out with (ABC).

 

[magictolight.com]

Great point, adjustment factors are easy to overlook. 310.15(b)(2)(a) table