parallel supply side bonding jumper sizing

[Talley1013]

Hello all. I'm sure this is a topic that has been beat to death and I apologize for bringing it up again. I tried to search for an answer but I guess my search-fu isn't very good.

I need help sizing supply side bonding jumpers. I need to bond 2 parallel conduits ahead of the service disconnect. If I bond each conduit separately can I size the bonding jumpers based on the size of the conductors in each conduit or do I have to size it based on the combined size of the parallel conductors?

The situation is 2 rigid service risers that need to be bonded. Each conduit contains 3)350 mcm & 1)1/0. The plan is to kerney onto the service neutral from each conduit and bond to the
conduits separately. Does each bonding jumper need to be sized for 350 mcm or 700 mcm? What is the code reference for this situation?

Thanks for the help. I appreciate it.

 

[infinity]

For individual jumpers it's based on the size of the conductors within the raceway:

250.102(C)(2) Size for Parallel Conductor Installations. Where the
ungrounded supply conductors are paralleled in two or
more raceways or cables, and an individual supply-side
bonding jumper is used for bonding these raceways or
cables, the size of the supply-side bonding jumper for each
raceway or cable shall be selected from Table 250.66 based
on the size of the ungrounded supply conductors in each
raceway or cable. A single supply-side bonding jumper in-
stalled for bonding two or more raceways or cables shall be
sized in accordance with 250.102(C)(1).

 

[Talley1013]

Thank you so much. That is exactly what I was looking for.

 

[infinity]

Here's a graphic from Mike: