Parallel Feeds in One Conduit

[naplespete57]

Parallel Feeds in One Conduit
We are one of two ECs on site. We planned on running parallel feeds to our Control Cabinet. Material purchased etc. However, the other EC allowed for a single conduit coming out of their switch gear.

Would it be code compliant to run a parallel feed in two conduits from our Control Cabinet to a larger pull box above the switchgear? At that point we would run all 6 phase wires into the gear through one conduit.

Beyond de-rating, what are my other considerations?

 

[Carultch]

Parallel Feeds in One Conduit
We are one of two ECs on site. We planned on running parallel feeds to our Control Cabinet. Material purchased etc. However, the other EC allowed for a single conduit coming out of their switch gear.

Would it be code compliant to run a parallel feed in two conduits from our Control Cabinet to a larger pull box above the switchgear? At that point we would run all 6 phase wires into the gear through one conduit.

Beyond de-rating, what are my other considerations?

There shouldn't be other concerns besides fill geometry and ampacity bundling adjustments. I take it you've already anticipated those.

 

[dkidd]

Two full-sized grounds, if wire is used for grounding.

 

[Carultch]

Two full-sized grounds, if wire is used for grounding.

Not true. 250.122(F).

One full size EGC per raceway.

 

[Dennis Alwon]

Not true. 250.122(F).

One full size EGC per raceway.

I think that is what he meant by 2... not 2 per raceway

 

[kwired]

Not true. 250.122(F).

One full size EGC per raceway.

One full size if one raceway, two full size if two raceways, three full size if three raceways....

One raceway will likely need larger current carrying conductors because of necessary ampacity adjustments, multiple raceways will need multiple EGC's, full sized. There is some give and take, but one method may be better in some cases and the other method better in other cases.

 

[dkidd]

One full size if one raceway, two full size if two raceways, three full size if three raceways....

One raceway will likely need larger current carrying conductors because of necessary ampacity adjustments, multiple raceways will need multiple EGC's, full sized. There is some give and take, but one method may be better in some cases and the other method better in other cases.

The one conduit will probably be a very short nipple. Derating wouldn't be required.

 

[kwired]

The one conduit will probably be a very short nipple. Derating wouldn't be required.

Maybe, if there wasn't provisions to get two raceways into the gear to begin with, it very well may need more then two feet before there is room for a transition box.

 

[Smart $]

O...
One raceway will likely need larger current carrying conductors because of necessary ampacity adjustments, multiple raceways will need multiple EGC's, full sized. There is some give and take, but one method may be better in some cases and the other method better in other cases.

The one conduit will probably be a very short nipple. Derating wouldn't be required.

Maybe, if there wasn't provisions to get two raceways into the gear to begin with, it very well may need more then two feet before there is room for a transition box.

310.15(A)(2) Exception may be applicable... but I wonder how that Exception works if changing the number of conductors...!!!

 

[dkidd]

310.15(A)(2) Exception may be applicable... but I wonder how that Exception works if changing the number of conductors...!!!

Where does OP say the number of conductors would change?

 

[Smart $]

Where does OP say the number of conductors would change?

Doesn't.

Just a thought that popped in my head. It was a carry over from another thread that used parallel for voltage drop then wanted to go back to single conductor near the circuit termination. There's no consideration in 310.15(A)(2) Exception for such a circumstance.

Not trying to hijack the thread BTW.

 

[kwired]

310.15(A)(2) Exception may be applicable... but I wonder how that Exception works if changing the number of conductors...!!!

Number of conductors in raceway is a reason to need to change ampacity, just like a different ambient temp could change it also. I think one could use that exception if you meet the conditions Go up to 10 feet from switchgear all in one raceway possibly because you don't have the room to enter with two raceways, in the spot you want to hit anyway, then split into two raceways. But to be able to use the full 10 feet you must have a 100 foot feeder, otherwise you are limited to 10% of feeder length.

 

[Smart $]

Where does OP say the number of conductors would change?

BTW... I was referring to the number of conductors in the conduit. My brain must have gotten side tracked. Seems to be happening more lately. One of the medications I am taking supposedly can cause confusion...

Number of conductors in raceway is a reason to need to change ampacity, just like a different ambient temp could change it also. I think one could use that exception if you meet the conditions Go up to 10 feet from switchgear all in one raceway possibly because you don't have the room to enter with two raceways, in the spot you want to hit anyway, then split into two raceways. But to be able to use the full 10 feet you must have a 100 foot feeder, otherwise you are limited to 10% of feeder length.

Exactly what I was attempting to point out.