Grounding riser

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Dexie123

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I have a situation where a 500 cable is run in a conduit to pick up various grounding bars in different locations in a building. In some cases there are pull boxes to allow for points of pulling.

Question. Does this 500 need to be bonded to the box in every location that there is a box, only when the wire is splves at that box location, both, or neither?
 
What you are asking about I consider a bonding jumper. Code is not specific, but I believe bonding at each enclosure is advisable.
250.96 Bonding Other Enclosures.

(A) General. Metal raceways, cable trays, cable armor,
cable sheath, enclosures, frames, fittings, and other metal
non–current-carrying parts that are to serve as equipment
grounding conductors, with or without the use of supplementary
equipment grounding conductors, shall be bonded
where necessary to ensure electrical continuity and the capacity
to conduct safely any fault current likely to be imposed
on them. Any nonconductive paint, enamel, or similar
coating shall be removed at threads, contact points, and
contact surfaces or be connected by means of fittings designed
so as to make such removal unnecessary.
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I don't think it is code required, but a good idea. Metal circumfrencially around a ground electrode conductor makes it into an inductor. Bonding along the way reduces that affect.
 
what of there is a spice. Then it is required no?

Also in terms of your GEC 250.64(E) mandates that you do bond the conduit (metal) on every end and within splice boxes correct?
 
Dexie123 said:
what of there is a spice. Then it is required no?
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Assuming the enclosure is conductive:
  • If it's a bonding jumper, not required explicitly.
  • If it's a GEC, see below.
  • If it's an EGC, required if circuit conductors are spliced in the enclosure. Also when not adequately bonded by other means.


Also in terms of your GEC 250.64(E) mandates that you do bond the conduit (metal) on every end and within splice boxes correct?
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It's debatable whether 250.64(E) requires interim enclosures to be bonded. That section can be interpreted as meaning bonded at only entry and exit, or at each end of each raceway section and enclosure. For an example of the latter interpretation, a conduit-box-conduit-enclosure run would have to be bonded where each "x" is: (x)conduit(x)box(x)conduit(x)enclosure(x)

My interpretation is at least entry and exit (if any), and I'd bond any interim enclosures and use 250.92(B)(2) through (B)(4) ensured bonding methods. It would make the previous example: (x)conduit-box-conduit-enclosure, where underlined indicates bonding to the enclosure or box rather than the ends of raceways and enclosures... but that's JMO.

FWIW, I have not run across one instance in my life where a GEC has passed through an enclosure, so I don't really think about it until someone brings it up on this forum... :angel:
 
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