Bonding isolated rigid pipe section

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Coppersmith

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
I'm running about 30 feet of rigid conduit underground. Both ends turn up out of the ground and transition to PVC, i.e. the rigid is not bonded to any other part of the system. I think I'm required to bond it. One end is a few inches away from a ground rod. Is it compliant if I put an exterior clamp on the pipe and bond it to the ground rod? The ground rod is a supplemental for a subpanel. The conduit is carrying the feeder for that same subpanel.
 
250.86 exception 3 would allow a metal elbow not bonded to EGC if buried below 18 deep, but that is only thing mentioned there is the elbow.
 
kwired said:
250.86 exception 3 would allow a metal elbow not bonded to EGC if buried below 18 deep, but that is only thing mentioned there is the elbow.
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Based on my reading of 250.86 I'm required to connect the pipe to the Equipment Grounding Conductor. I've connected it to the Grounding Electrode Conductor (which is about 5 feet from the subpanel ground buss). Am I compliant? I don't know how I would connect to the EGC since the metal pipe does not terminate in a box where I can attach a grounding bushing.
 
Coppersmith said:
Based on my reading of 250.86 I'm required to connect the pipe to the Equipment Grounding Conductor. I've connected it to the Grounding Electrode Conductor (which is about 5 feet from the subpanel ground buss). Am I compliant? I don't know how I would connect to the EGC since the metal pipe does not terminate in a box where I can attach a grounding bushing.
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It must be bonded to the EGC for the circuit that is in the conduit.
 
wwhitney said:
Put in a rigid C-condulet at the rigid-PVC transition, and bond the EGC to the C-condulet as it passes through?

Cheers, Wayne
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I'm pretty sure that a condulet or a box is supposed to remain accessible. He wants to bury the whole thing.

@Coppersmith

Why not just do the whole thing with RMC or with PVC?
 
jaggedben said:
I'm pretty sure that a condulet or a box is supposed to remain accessible. He wants to bury the whole thing.
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I'm pretty sure he's using RMC to keep the required cover down to 6", so with an RMC elbow, if the end of the elbow isn't above grade, a short RMC nipple would get it above grade.

Cheers, Wayne
 
wwhitney said:
I'm pretty sure he's using RMC to keep the required cover down to 6", so with an RMC elbow, if the end of the elbow isn't above grade, a short RMC nipple would get it above grade.

Cheers, Wayne
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If that is the reason, the question is still why not run RMC the entire run? Why transition to PVC for the riser out of the ground which is probably a rather insignificant length compared to the rest of the run, unless maybe you need to make some bends out of the ground and don't have equipment to bend the RMC?? 1/2 - 1" can be bent with next size larger EMT hand benders though. Many have at least a 1/2 and 3/4 EMT hand bender.
 
jaggedben said:
Why not just do the whole thing with RMC or with PVC?
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wwhitney said:
I'm pretty sure he's using RMC to keep the required cover down to 6", so with an RMC elbow, if the end of the elbow isn't above grade, a short RMC nipple would get it above grade.
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Yes, that is the reason. I don't like digging any deeper than I have to. The 90 turns above the grade.

kwired said:
If that is the reason, the question is still why not run RMC the entire run? Why transition to PVC for the riser out of the ground which is probably a rather insignificant length compared to the rest of the run, unless maybe you need to make some bends out of the ground and don't have equipment to bend the RMC?? 1/2 - 1" can be bent with next size larger EMT hand benders though. Many have at least a 1/2 and 3/4 EMT hand bender.
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1.5" RMC. No I don't have a bender or a threader for that. I could have run the panel end entirely in RMC but it would have been a major hassle going up the wall, to an LB and thru the wall with all rigid. PVC is so much easier, cheaper, and more flexible. 1.5" RMC is $43 a stick. Compression couplings $17 each. I wanted to use IMC but none of the supply houses within 50 miles had it in stock.

I'll reiterate: How does one attach an EGC to an isolated section of pipe? Am I allowed to run a ground wire outside the pipe and clamp it on?
 
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300.2 (B) (2) Grounding and Bonding Conductors. Equipment ground‐
ing conductors shall be permitted to be installed outside a race‐
way or cable assembly where in accordance with the provisions
of 250.130(C) for certain existing installations or in accordance
with 250.134(B), Exception No. 2, for dc circuits. Equipment
bonding conductors shall be permitted to be installed on the
outside of raceways in accordance with 250.102(E).
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so let's take a look, 250.130C has 6 options, including>>>

250.130(C) (1) Any accessible point on the grounding electrode system
as described in 250.50
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That G rod is looking good....assuming it all considered existing installation

250.134(B) EX 2 is about DC, no soap....

however>>>

250.130(C)(2) Outside a Raceway or an Enclosure. If installed on the
outside, the length of the bonding jumper or conductor or
equipment bonding jumper shall not exceed 1.8 m (6 ft) and
shall be routed with the raceway or enclosure.

Exception: An equipment bonding jumper or supply-side bonding
jumper longer than 1.8 m (6 ft) shall be permitted at outside pole loca‐
tions for the purpose of bonding or grounding isolated sections of metal
raceways or elbows installed in exposed risers of metal conduit or other
metal raceway, and for bonding grounding electrodes, and shall not be
required to be routed with a raceway or enclosure.
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that would appear to be the options i can find this a.m.

~RJ~
 
ActionDave said:
No. 300.3(B)
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wwhitney said:
Wouldn't 250.102(E) allow what Coppersmith proposes?
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250.102(E)(2) does seem to conflict with 300.3(B) unless an "equipment bonding jumper" is different than the EGC and bonding conductors referred to in 300.3(B). I getting a bit confused as to if they are the same or not.

250.102(E) Installation. Bonding jumpers or conductors and
equipment bonding jumpers shall be permitted to be installed
inside or outside of a raceway or an enclosure.
(2) Outside a Raceway or an Enclosure. If installed on
the outside, the length of the bonding jumper or conductor
or equipment bonding jumper shall not exceed 1.8 m (6 ft)
and shall be routed with the raceway or enclosure.

300.3(B) Conductors of the Same Circuit. All conductors of
the same circuit and, where used, the grounded conductor
and all equipment grounding conductors and bonding conductors
shall be contained within the same raceway, auxiliary
gutter, cable tray, cablebus assembly, trench, cable, or
cord, unless otherwise permitted in accordance with
300.3(B)(1) through (B)(4).

Grounding Conductor, Equipment (EGC). The conductive
path(s) that provides a ground-fault current path and connects
normally non–current-carrying metal parts of equipment
together and to the system grounded conductor or to the
grounding electrode conductor, or both.

Bonding Conductor or Jumper. A reliable conductor to
ensure the required electrical conductivity between metal
parts required to be electrically connected.

Bonding Jumper, Equipment. The connection between two
or more portions of the equipment grounding conductor.
 
it's not doing my adhd much good this morning either Copper :(, what was the old addage?

Not all bonding is grounding, but all grounding is bonding?

~RJ~
 
OK, I need a little more help here. The inspector is giving me a hassle. He says I need to change the PVC riser to metal pipe and run it to the panel and put a grounding bushing on. I think I'm good the way it is:

I don't see how he can dictate raceway choice.

There is a EGC in the pipe with the other conductors. (300.3)

The metal elbow end of the pipe run is about 5ft from the panel and is bonded using an external clamp and an external wire which closely follows the pipe. (250.86) (250.102(E)(2))

The only place I vary from the NEC is I am using a jumper from the grounding electrode conductor since the ground rod is 2 inches from the metal elbow. (The wire actually hits the pipe first, then goes to the ground rod. One continuous wire.) I think that is fine and the inspector has not said anything about it but I could run a second "equipment bonding jumper" if necessary. They both originate on the ground bar.

The definition of bonding conductor seems to indicate it can be one-in-the-same with the grounding electrode conductor.

Bonding Conductor or Jumper. A reliable conductor to
ensure the required electrical conductivity between metal
parts required to be electrically connected.

Am I right or wrong?
 
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