Utility supplying switchgear

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Capital

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morris plains nj
480v, 3000amp, service supplied from a vault on cable tray, from the tray out of the vault conduit is used and connected directly in the back of the switchgear. My question is, can the phase conductors be run separately through the conduit. ie: all the parallel condutors phase 1 in conduit #1, phase conductors phase 2 in conduit #2 and so on.
 
Negative. Each conduit should contain every phase and, where present, a neutral.

Your proposal would lead to heating of the conduits due to induction.
 
The conduits area actually 14" nipples making the transition through the fire wall from the vault, does that make a difference? Also does each phase need to be bundled on the cable tray in the vault? The Utility controls the vault, should they be making this decision?
 
If you install them phase isolated through ferrous nipples or ferrous cutouts, you will get inductive heating.

Can you make a fiberglass or aluminum trough of some type so the phases and neutral/ground commingle?
 
Capital said:
480v, 3000amp, service supplied from a vault on cable tray, from the tray out of the vault conduit is used and connected directly in the back of the switchgear. My question is, can the phase conductors be run separately through the conduit. ie: all the parallel condutors phase 1 in conduit #1, phase conductors phase 2 in conduit #2 and so on.
Click to expand...

take a look at:

300.3 (B)(1)
300.3 (B)(3)
and
300.20

You might be able to convince yourself you can do this if all the raceways are non-ferrous and you cut a big chunk out of the back of the switchgear skin and replace it with aluminum. How the inspector will see it is something else. Might want to pass it by him first.
 
We decided on conduit from the vault to the switchgear room, it made it easier to maintain the fire rating of the room. Another question, in the switchgear room, the electrician wants to run the conductors on cable tray into the switchgear, no conduit. This will leave exposed conductors on the tray with no OCPD, acceptable?
 
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