250.102

[tmkelly1]

I have (6) 2" pvc conduits coming from a meter stack going to a common pullbox. From the pullbox I am taking MC to feed the unit panel in 6 different units. As I interpret 250.102 (d) [2nd paragraph] "A single common continuous equipment bonding jumper shall be permitted to bond 2 or more raceways or cables where the bonding jumper is sized......for the largest overcurrent device supplying the circuits therein."
The largest overcurrent device is 125a.
So as long as I take a #6 cu. conductor in one of the pvc conduits the box and the 6 MC cables are bonded properly. And it isn't necessary to pull a bond wire in each of the conduits to effectively bond the box and MC's.
The bond wire lands on a buss bar, which is also jumped to the pullbox, and the MC cable ground wires are also landed on that bus bar.
The single conductor is large enough to clear any ground fault likely to be imposed on it.
It certainly has caused a stir around here with people lining up on both sides. And of course the inspector doesn't like it.
And I don't think that induction would play much of a part in it.
let me hear some good arguments against it or for it.

 

[petersonra]

Re: 250.102

I think you want to run just one EGC in one of the PVC conduits. I suspect you will find you have to run one in each conduit, as an EGC has to be run with any set of conductors.

I am curious why you need a 2" conduit for a system with a 125A main.

 

[tmkelly1]

but isn't the whole purpose of the egc to bond the raceway and equipment?
And it has to be bonded for the largest overcurrent device on the "circuits contained therein"
And the 2" wasn't necessary it was just done that way.

 

[infinity]

You're confusing a bonding jumper with the EGC that is required within the feeder for each unit panel.

215.6 Feeder Conductor Grounding Means.
Where a feeder supplies branch circuits in which equipment grounding conductors are required, the feeder shall include or provide a grounding means, in accordance with the provisions of 250.134, to which the equipment grounding conductors of the branch circuits shall be connected.

250.134 Equipment Fastened in Place or Connected by Permanent Wiring Methods (Fixed) ? Grounding.
Unless grounded by connection to the grounded circuit conductor as permitted by 250.32, 250.140, and 250.142, non?current-carrying metal parts of equipment, raceways, and other enclosures, if grounded, shall be grounded by one of the following methods.
(A) Equipment Grounding Conductor Types. By any of the equipment grounding conductors permitted by 250.118.
(B) With Circuit Conductors. By an equipment grounding conductor contained within the same raceway, cable, or otherwise run with the circuit conductors.

You need to run the EGC within the same raceway or cable as the feeder conductors to provide a grounding means at the unit panels.