NEC/ 3/0 and # 14 in same conduit

Status
Not open for further replies.
J

jaybob12

New member
Can three 3/0 and # 14 be ran in the same conduit? PVC 2-1/2'' underground I am worried 3/0 may damage # 14 insulation anything in the NEC that says NO?
 
I don't think the NEC has a prohibition against this. The only requirement I know of is that all wires have to have an insulation system rated for the highest voltage in the conduit. 300.3(C).

Welcome to the forum.
 
charlie b said:
I don't think the NEC has a prohibition against this. The only requirement I know of is that all wires have to have an insulation system rated for the highest voltage in the conduit. 300.3(C).

Welcome to the forum.
Click to expand...

And the 3/0 is not service conductors.
 
Could they be control wires? Did a large boiler house for the Air Force once, their drawings showed 2 # 14's with all of the motor feeders for a lockable E-stop at each motor.
 
If it is a generator install, and the 14 AWG conductors are from a control circuit that originates from a Class 2 source, those 14s cannot be in the same raceway.





*Note:
The manufacturer can provide a whip with the control conductors in the same raceway, but it cannot be field wired in such a manner.
 
Pierre C Belarge said:
If it is a generator install, and the 14 AWG conductors are from a control circuit that originates from a Class 2 source, those 14s cannot be in the same raceway.





*Note:
The manufacturer can provide a whip with the control conductors in the same raceway, but it cannot be field wired in such a manner.
Click to expand...

I agree completely.

However I think I have read a set of instructions for an Automatic Transfer Switch that stated to run the (Class 2) control wires in the same 1.25" raceway as the power feed.

I thought 725.136(A) would overrule 110.3(B) on that one. :roll::cool:
 
If there is any length to the run, it is somewhat likely that the 14s will break when pulled around the 90s if there are any. We often install our #14, 120 volt motor control circuit conductors in the same raceway with motor conductors but only if the motor conductors are #4 or smaller. Where the motor conductors are larger than #4 we run a second conduit for the control conductors.
 
Status
Not open for further replies.
Top