Bonding jumpers in parallel, again.

[electrofelon]

I know we have been over supply-side bonding Jumpers in parallel, and how the code is a little ambiguous on this, not specifically stating the allowance for running supply-side Jumpers in parallel sized to each raceway like grounding electrode conductor taps. for example let's just take the simple case of a CT cabinet that needs to be bonded "indirectly" from the service panel downstream from it with a SSBJ where there are parallel raceways between the two. Can I run a single supply-side bonding jumper through 1 of the parallel raceways? It seems not, since 300.3(B) which specifically mentions bonding conductors. 300.3(B)(2) permits grounding and bonding conductors outside of raceways, but that seems to dance around allowing 1 in a single of parallel raceways. Do I need to either run outside of the raceways or run a full-sized in each one?

 

[texie]

You need a SSBJ in each raceway. See 250.102(C)(2). The good news is this is different than an EGC in that it only needs to be sized for the conductors in each raceway.

 

[electrofelon]

You need a SSBJ in each raceway. See 250.102(C)(2). The good news is this is different than an EGC in that it only needs to be sized for the conductors in each raceway.

Texie,. That seems to only be talking about bonding the raceway (s) itself, and not passing an ssbj through them for another purpose. Basically I want to run an ssbj in parallel. I don't know if I can just go by 300.3(B)(1) and do it?

 

[infinity]

GEC's and bonding jumpers cannot be run in parallel where you're using parallel smaller conductors to create the code required single larger one.

 

[electrofelon]

GEC's and bonding jumpers cannot be run in parallel where you're using parallel smaller conductors to create the code required single larger one.

If I may play devil's advocate here: 300.3(B) seems to allow it. 300.3(B)(1) seems to only direct the reader to 250.122 for EGC's.

 

[don_resqcapt19]

The code permits the CT cabinet to be bonded to the service neutral and a supply side bonding jumper is not needed.

 

[electrofelon]

The code permits the CT cabinet to be bonded to the service neutral and a supply side bonding jumper is not needed.

Correct, but what if I want to do it the other way, with a SSBJ back to the MDP.

 

[infinity]

If I may play devil's advocate here: 300.3(B) seems to allow it. 300.3(B)(1) seems to only direct the reader to 250.122 for EGC's.

I just don't see anything that says that smaller GEC's or bonding jumpers can be paralleled to make a larger conductor. Various sections of the NEC direct you to a few tables and those tables give you the minimum size single conductor required. Those tables are for single conductors only. If permitted it would be easy enough to have a note to the table stating that multiple parallel conductors are permitted to make a single larger one.

 

[don_resqcapt19]

It appears to me that using Table 250.102(C)(1) and installing a supply side bonding jumper in each raceway will result in more copper than installing a single supply side bonding jumper based on the table. If you are installing the SSBJ in the raceways, I am going to require one in each raceway because of the parallel conductor rules in 310.

However, as Rob said, there is no actual language that says this. Probably an oversight in the code that needs to be looked at. There is no reason not to permit the paralleled SSBJs as that installation creates a bonding jumper larger than what a single SSBJ would be.

 

[electrofelon]

I just don't see anything that says that smaller GEC's or bonding jumpers can be paralleled to make a larger conductor.

300.3 and 310.10(H) generally apply which allow paralleling. Isnt that what paralleling is: dividing a conductor into multiple smaller ones? I dont see a "full size in each raceway" type statement like 250.122 has. 310.10(H)(6) directs the reader to size per 250.102(C). Unfortunately the wording in 250.102(C) is rather poor as the part dealing with paralleling seems to assume you are bonding parallel raceways, not wanting to run a SSBJ in (borrowing dons emphasis on the "in" technique).