bonding ground bushing to equipment

[ga1212ett]

hello,
what NEC article should i be using to size ground wires for ground bushings bonding to equipment. (required per job specs) ,equipment is an mcc fed from a utility meter box, with a main disconnect between the meter and MCC. They just specify to bond the bushings to ground bus without actual sizing requirements listed.
More information, the Main is 1600A breaker with 6 sets of parallel 350mcm copper conductors per phase and 250 mcm ground per set. 480v, no neutral.
the conduit is pvc underground with pvc coated rigid conduit risers.
the MCC is open bottom and will not have continuity with the risers without this bonding conductor.

Thanks for your time.

 

[david]

if you are asking about a main bonding jumper that would be 12 1/2 % of your equivalent CM
(350 X 6)

 

[Dennis Alwon]

Look at the notes to T 250.102(C)(1)

 

[augie47]

Dennis directed you to the correct Table for sizing.
Note that if you run A bonding jumper for all the bushings the 12-1/2% rule will be in effect, however, if you run a bonding jumper for each individual conduit the jumper can be sized by the conductors in the one conduit.
Most folks find the second option preferable due to lug sizing and ease of installation.

 

[ga1212ett]

thank you for clearing that up for me, guys.

 

[infinity]

Aren't these are feeder conductors, if so the correct table is 250.122. Since your 6 sets of 350's are increased in size then 250.122(B) would also apply.

 

[augie47]

Aren't these are feeder conductors, if so the correct table is 250.122. Since your 6 sets of 350's are increased in size then 250.122(B) would also apply.

excellent catch.. I had to re-read the OP to see there was a disconnect ahead of the MCC (I assume with OCP).
(can I blame it on DEnnis' post )

 

[infinity]

excellent catch.. I had to re-read the OP to see there was a disconnect ahead of the MCC (I assume with OCP).
(can I blame it on DEnnis' post )

Yeah we can blame him.

Let's hope that the OP comes back for the update.

 

[ga1212ett]

i did come back, just in time.

 

[infinity]

Assuming that the 250 kcmil EGC in each raceway is the proper size you can just wrap that around the bonding bushing on each raceway.