1-phase and 3-phase in a single conduit wire

[Starter122]

Can anybody advice me if there's any restriction in the NEC about having a single phase and three phase circuit (wires) on a single conduit?

 

[charlie b]

There is no rule that would prohibit having both 1 phase and 3 phase wires in the same conduit. However, there are two related rules. One says that you must de-rate every conductor's ampacity, when there are four or more current-carrying conductors in the same conduit. The other gives a limit of 40% for the amount of the internal area that the conductors are permitted to occupy.

 

[raider1]

First off welcome to the forum.

You can place 1 phase and 3 phase circuits in the same raceway but you must also take into account derating if you have more than 3 current carrying condutors in the conduit. Take a look at 310.15(B)(2)(a).

Chris

 

[Starter122]

Thanks for all your reply. You really make it sound so simple to understand. :smile:

 

[acrwc10]

Thanks for all your reply. You really make it sound so simple to understand. :smile:

Oh just wait , we all have a way of making it sound not so simple, you just haven't asked the right question yet. :grin:

 

[don_resqcapt19]

Don't forget about the identification rules in 210.5(C) and, if there is a grounded conductor, the one in 200.6(D).