Running multiple circuits - thru floor conduits

[designer82]

Say I have a panelboard on floor 1 that powers circuits on floor 2 and multiple circuits are run in the thru-floor conduit sleeve.

How does this work considering the cable sizing in the NEC table is for no more than 3 current carrying conductors in conduit.

There would be more than 3 going thru the thru-floor conduit sleeve, enough for all circuits on this 2nd floor.

Thanks

 

[infinity]

How long is the sleeve? Less than 24" no derating required if the rest of the cable runs are not bundled.

 

[tom baker]

You mention cable sizing and then conductors, what cable sizing table are you referring to?
Is this application conductors/wire, IE THHN/W in a raceway? If so adjust ampacity per table 310.15 C 1, but you start at the 90 Deg C rating.

 

[designer82]

Ok I think I understand. You can run multiple circuits/conductors thru a sleeve without derating the conductors as long as the sleeve is 24" or less.

Just for clarity, is this how an electrician would run it... Cut/cap the conduits just before the sleeve and run conductors thru the sleeve?

Conduit-FLoor-Sleeve

Image Conduit-FLoor-Sleeve hosted in ImgBB

ibb.co

 

[tom baker]

If you are talking about individual conductors, then no. Just run the raceway/conduit (EMT is not conduit) thru a sleeve. Firestop around the raceway/conduit, per the firestop instructions.
The conductors in the raceway system would be adjusted for ampacity.
The raceway has to be continuous (110.8)
I am not very familiar with firestopping there are others that do it all the time. Perhaps you are thinking the individual conductors have to be firestopped, no, just the penetration, but the wiring method has to be suitable for the occupancy.
There is only one section on firestopping in the NEC, firestopping is typically inspected by the building AHJ

 

[designer82]

I think the better question is... If an electrician needs to run 2 circuits, each in conduit, would they always make 2 core drills and run the two conduits or would they make 1 core drill with one larger conduit.

Picture below is what I mean. I'm thinking it will always be option A but it would be good to get confirmation

Conduit-FLoor-Sleeve2

Image Conduit-FLoor-Sleeve2 hosted in ImgBB

ibb.co

 

[tom baker]

See 110.8

 

[tom baker]

Most would run 2 circuits in one raceway, watch adjustments for fill.

 

[infinity]

I think the better question is... If an electrician needs to run 2 circuits, each in conduit, would they always make 2 core drills and run the two conduits or would they make 1 core drill with one larger conduit.

So the entire run for each of the two is in conduit?

 

[designer82]

So the entire run for each of the two is in conduit?

yes let's assume it is

 

[tom baker]

I think the better question is... If an electrician needs to run 2 circuits, each in conduit, would they always make 2 core drills and run the two conduits or would they make 1 core drill with one larger conduit.

ten electricians will install a conduit job differently, and all to code.

 

[LarryFine]

How does this work considering the cable sizing in the NEC table is for no more than 3 current carrying conductors in conduit.

More than three CCCs are permitted in a single conduit; more than three merely means de-rating applies.

 

[tom baker]

Like I said, 310.15 C 1

 

[infinity]

ten electricians will install a conduit job differently, and all to code.

This sounds hypothetical and there are too many unknown variables to answer one way or another. Some guys would run 2 conduits because they only work with small size raceways. Another guy will run one large conduit because it may save labor and materials. If we're talking about a few 20 or 30 amp circuits then that would be different.

 

[designer82]

This sounds hypothetical and there are too many unknown variables to answer one way or another. Some guys would run 2 conduits because they only work with small size raceways. Another guy will run one large conduit because it may save labor and materials. If we're talking about a few 20 or 30 amp circuits then that would be different.

Thanks, appreciate the responses.

Just wondering if this is how they would execute it if they chose to run one large conduit sleeve instead of multiple smaller conduits...

conduit-sleeve

Image conduit-sleeve hosted in ImgBB

ibb.co

 

[infinity]

Thanks, appreciate the responses.

Just wondering if this is how they would execute it if they chose to run one large conduit sleeve instead of multiple smaller conduits...

That image shows the conductors leaving the raceways and going into the sleeve. That is not permitted.

 

[designer82]

That image shows the conductors leaving the raceways and going into the sleeve. That is not permitted.

Ah ok, so the only way then is to run both conduits thru the sleeve?

 

[infinity]

Ah ok, so the only way then is to run both conduits thru the sleeve?

Yes.