Multi set service conduits

[vicdelta]

I have 4 set of 350 MCM parallel service conductors, which are tapped to main service tap Pull box with lug landings.This set is feeding a 1200A Switchboard with 1200A Main CB.The conduit runs are Non Metalic conduit(PVC) from Pull Box to Main Switchboard.From same Tap Pull Box also I am getting one set of Feedes to a 400A Switchboard with400A CB.I am bonding the neutral in each switchboard based on their Largest Feeder Cables.Do I need to bond the neutral in Tap pull box where the Lug landings are,or at each switchboard
Bonded neutral is OK.By bonding I mean Neutrals are bonded to water pipe and Ufer Ground.Do I need to run Equipment ground conductor in service Conduits back to Tap box where service conductors are originated.
Since these two services are fed from same Service Tap Pull Box with PVC conduit,how do I have to approach to size the GEC (Ufer Ground and CW Pipe),also,where I should Bond the neutral to comply with 250-52,250-66.
The tap pull box is fed by 3 sets of 750 Kcmil Over Head service Conductors per phase.
Thanks

 

[bob]

I have 4 set of 350 MCM parallel service conductors, which are tapped to main service tap Pull box with lug landings.This set is feeding a 1200A Switchboard with 1200A Main CB.The conduit runs are Non Metalic conduit(PVC) from Pull Box to Main Switchboard.From same Tap Pull Box also I am getting one set of Feedes to a 400A Switchboard with400A CB.

I would ask how you determined the 4 - 350 cu(ampacity 1240 amps) to feed the 1200 amp and the 400 amp panel?

I am bonding the neutral in each switchboard based on their Largest Feeder Cables.Do I need to bond the neutral in Tap pull box where the Lug landings are,or at each switchboard.

See 250.24(A)(1)

Bonded neutral is OK.By bonding I mean Neutrals are bonded to water pipe and Ufer Ground.Do I need to run Equipment ground conductor in service Conduits back to Tap box where service conductors are originated.

No need to run an EGC to tap box. It is bonded to the neutral. Read 250.24
A thru E.

Since these two services are fed from same Service Tap Pull Box with PVC conduit,how do I have to approach to size the GEC (Ufer Ground and CW Pipe),also,where I should Bond the neutral to comply with 250-52,250-66.
The tap pull box is fed by 3 sets of 750 Kcmil Over Head service Conductors per phase.
Thanks

How far is the tap box from the 1200 amp main and 400 amp main?
The GEC is determined from 250.66. The 1200 amp main needs a 3/0 and the 400 panel needs a 1/0.

 

[chris kennedy]

I have 4 set of 350 MCM parallel service conductors, which are tapped to main service tap Pull box with lug landings.

This has to be one big a_ _ pull box. Has to be 36" by 36" absloute minimum. How big is it?

 

[vicdelta]

Pull section size

Pull section size

This has to be one big a_ _ pull box. Has to be 36" by 36" absloute minimum. How big is it?

The pull section size is 90"x42"x14-1/2" Rated 1600Amps,208/120V 3P 4W.

 

[vicdelta]

Reply

Reply

I would ask how you determined the 4 - 350 cu(ampacity 1240 amps) to feed the 1200 amp and the 400 amp panel?

(The main Service Conductors are set of (4)750 Kcmil per phase.
(The 1200Amp Service tap conductors are set of (6)4/0 AWG per phase).
(the 400 Amp Service tap conductors are set of (2) 350 MCM per phase).

See 250.24(A)(1)

No need to run an EGC to tap box. It is bonded to the neutral. Read 250.24
A thru E.


How far is the tap box from the 1200 amp main and 400 amp main?
The GEC is determined from 250.66. The 1200 amp main needs a 3/0 and the 400 panel needs a 1/0.

Main service Pull section is 50 feet away from 1200A and 400A Service disconnects.