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#95468 09/15/05 01:42 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Ryan

Quote
How is the bonding jumper installed in parrallel when there is only one?

It isn't and does not have to be.

Quote
Where the service-entrance conductors are paralleled in two or more raceways or cables, the equipment bonding jumper, where routed with the raceways or cables, shall be run in parallel.

I am talking about a bonding jumper that does not leave the enclosure.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#95469 09/15/05 05:50 PM
Joined: Mar 2003
Posts: 29
M
Member
Quote
Originally posted by OVES:
Inspector said that 250.102(C) requires each conduit to be bonded independently, not daisy-chained. If they are to be daisy-chined, then the ground wire must be increased to equal the sum of all of the conduits. Sounds crazy and I can't get that out of the text. Has anyone else run into an inspector with similar views?

He is correct in that the bonding jumper must be larger than 3/0 if the phase conductors are larger than 1100 kcmil, however nowhere in 250.102(C) does it say that you can't daisy chain the bonding conductor. Nor does it say that if you do "then the ground wire must be increased to equal the sum of all of the conduits. What it does say is this: The bonding jumper shall not be smaller than the sizes shown in Table 250.66 for grounding electrode conductors. Where the service-entrance phase conductors are larger than 1100 kcmil copper or 1750 kcmil aluminum,the bonding jumper shall have an area not less than 12½ percent of the area of the largest phase conductor.

You could theoretically have multiple conduits with a total of less than 1100 kcmil and then size that bonding jumper directly from table 250.66 even though it's being daisy chained through all of the bonding bushings. It's the total circular mils that determines sizing, not the fact that you've daisy chained it.

[This message has been edited by Mvannevel (edited 09-15-2005).]

[This message has been edited by Mvannevel (edited 09-15-2005).]

#95470 09/15/05 06:11 PM
Joined: Jan 2005
Posts: 9
M
Junior Member
nothing in 250.102 (C) prevents you from installing one bonding jumper for parallel
raceways or one from each raceway, 250.102 (D) is load side bonding and has nothing to do with 250.102 (C), if you want to install one bonding jumper from each raceway it is sized on largest phase conductor in that raceway, or one for all parallel raceways is
sized on the largest phase conductor, so if you have 4 500kcmil parallel, one bonding for all raceways would be 12 1/2 of 2000kcmil, if this is load side go to 250.102 (D) & table 250.122 and it is sized for the largest overcurrent device.

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