Service Installation

[quantum]

We are following a design to install a new service disconnect next to and paralleling an existing service. We will install a new 800A pole mounted disconnect and run the service to a new power building. The below grade conduit will be PVC-80 with rigid metal stub-ups to the disconnect and building main breaker.

My concern is this, there are 4 conduits. 3 of the 4 conduits each contain an A/B/C set with no ground conductor of any type. The 4th conduit has only a ground in it. To my knowledge, this is acceptable if the entire conduit runs were metallic start to finish. Am I misunderstanding something here?

 

[GoldDigger]

If it is really a service conductor set and not feeder, there is no need for an EGC, either raceway or wire, in the first place.
If the pole mounted 800A disconnect has OCPD it is probably the service disconnect, making the rest of the distance a feeder.

For a feeder set you need to have either raceway EGC or wire EGC for each set.
If the raceways qualify as EGC you can leave out the wire EGC. But once you choose to run a wire EGC there must be a full sized EGC for each set of parallel conductors.
However, what is the ground situation for the three phase? If it is a grounded wye and is service wiring there has to be a neutral in each set taken at least as far as the service disconnect.

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[infinity]

Is the 800A pole mounted disconnect the service disconnect? If so then your conductors are feeder conductors and require all conductors of each set in each raceway. Could the singe conductor in one raceway be a GEC? Also metal elbows need to be bonded unless they're buried a minimum of 18" below the surface of the ground.

 

[GoldDigger]

Is the 800A pole mounted disconnect the service disconnect? If so then your conductors are feeder conductors and require all conductors of each set in each raceway. Could the singe conductor in one raceway be a GEC? Also metal elbows need to be bonded unless they're buried a minimum of 18" below the surface of the ground.

And if the conductor is in fact a GEC, then a bond at each end of a ferrous metal elbow is still required regardless of burial depth.

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[quantum]

However, what is the ground situation for the three phase? If it is a grounded wye and is service wiring there has to be a neutral in each set taken at least as far as the service disconnect.

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No neutral, straight 480V.

The disconnect is being called "Service Disconnect", it is a non-fused disconnect, from there it energizes the building Main Circuit Breaker.

 

[quantum]

Is the 800A pole mounted disconnect the service disconnect? If so then your conductors are feeder conductors and require all conductors of each set in each raceway. Could the singe conductor in one raceway be a GEC? Also metal elbows need to be bonded unless they're buried a minimum of 18" below the surface of the ground.

it is being labeled as "Service Disconnect". It is a non-fused disconnect. The ground cable being ran in its own conduit between this pole mounted disconnect and the building Main Breaker is noted as "Main Bonding Jumper", I stumbled across this note last night. Once through the main breaker, all of the phase conductors and this ground cable (or bonding jumper as noted) end up in a trough and will be tapped to feed various VFDs.