Bonding Service Raceway.

[augie47]

I am inspecting a job where the E/C has installed a service consisting of (7) runs of 750 kcmil AL in 4" PVC conduits.
The conduits emerge from underground to a raceway and then are nippled from the raceway to the service via PVC nipples.
My original thought was a bonding jumper sized at 12-1/2% of the sum of the service conductors could be used to bond the raceway, however, in reading 250.102(C) it appears that each raceway will need a jumper based on the 750 kcmil.
Am I correct ?

 

[Smart $]

I am inspecting a job where the E/C has installed a service consisting of (7) runs of 750 kcmil AL in 4" PVC conduits.
The conduits emerge from underground to a raceway and then are nippled from the raceway to the service via PVC nipples.
My original thought was a bonding jumper sized at 12-1/2% of the sum of the service conductors could be used to bond the raceway, however, in reading 250.102(C) it appears that each raceway will need a jumper based on the 750 kcmil.
Am I correct ?

Yes... if running an individual bonding jumper to each [metal] raceway. I believe if a single bonding jumper is used for all seven raceways, you'd have to size it for the sum.

 

[augie47]

There is only one metal wireway,, with 7 PVC conduits entering and 7 PVC conduits leaving.
E/C knows he can bond using his grounded conductors.\
The service equipment is only 3 ft from the wireway and the original thought was (1) 750 from the service neutral to the wireway routed thru a conduit, but, it appears 250.102(C) requires a bond in each raceway if you have multiple raceways.

 

[don_resqcapt19]

Tell him to replace the metallic wireway with a non-metallic one.

I don't think that 250.102(C)(2) actually requires a supply side bonding conductor in each raceway, but I don't know how else you can do it.
You can't put a single supply side bonding jumper in one of the parallel raceways because of the rules in 310.10(H), and I don't think you can run the supply side bonding jumper in its own raceway.

 

[texie]

Based on your description, IMO the only compliant way to do this is with a bonding jumper in each PVC nipple sized for the conductors in each nipple. As mentioned, he can't use a single jumper based on the total KCMIL as you have to have the path thru EACH nipple.

 

[Joe Villani]

Bonding Service Raceway

Bonding Service Raceway

Let me throw this out there......

If I skinned each grounded conductor (they remain uncut) and install a 750 kcmil split bolt, run an uncut 750kcmil aluminum through each split bolt (also uncut) to each grounded conductor then bond it to the wireway would that be compliant?

Based on the situation it may be more work and more money but just looking for opinions.

Thanks

Joe Villani

 

[Smart $]

Let me throw this out there......

If I skinned each grounded conductor (they remain uncut) and install a 750 kcmil split bolt, run an uncut 750kcmil aluminum through each split bolt (also uncut) to each grounded conductor then bond it to the wireway would that be compliant?

Based on the situation it may be more work and more money but just looking for opinions.

Thanks

Joe Villani

I believe that would be compliant for a service entrance.

 

[zbang]

I'm not trying to over-think this, but assuming that the service mentioned in #1 is a bonded metal box, would it be compliant to replace a single PVC nipple with GRC? (Also assuming no concentric knockouts or other such rot; not that I would expect it when 4" pipes are in use.)

 

[Smart $]

I'm not trying to over-think this, but assuming that the service mentioned in #1 is a bonded metal box, would it be compliant to replace a single PVC nipple with GRC? (Also assuming no concentric knockouts or other such rot; not that I would expect it when 4" pipes are in use.)

IMO, yes... provided the GRC is properly bonded to its terminal enclosures. However, you'll run into those that interpret the bonded-to-grounded-conductor requirement to mean directly rather than through other bonded equipment.

 

[MasterTheNEC]

Let me throw this out there......

If I skinned each grounded conductor (they remain uncut) and install a 750 kcmil split bolt, run an uncut 750kcmil aluminum through each split bolt (also uncut) to each grounded conductor then bond it to the wireway would that be compliant?

Based on the situation it may be more work and more money but just looking for opinions.

Thanks

Joe Villani

Yes

And just as an added note. You are doing so do bond the Wireway (raceway) so you do have some options in Section 250.102(E) in how you route this Supply-Side Bonding Jumper.

 

[meternerd]

If it's a service, any wiring on the line side of the main disconnect is usually under the jurisdiction of the POCO, and they may have objections (ours would) with any neutral (grounded conductor) bonding connections ahead of the meter enclosure. We do not allow bonding of the neutral anywhere except at our transformer and in the main disconnect enclosure, and that section would have to be separate or barriered from the utility side, which is sealable. If the neutral lands on a bus ahead of the meter/disconnect, that bus would have to be on insulated standoffs. Neutral bond (including GEC) is considered a customer connection and is therefore not allowed in a sealable section. If the raceway has a removable cover, it would have to be sealable, since it contains unmetered conductors. I don't think that's a standard, though. Just a requirement for many utilities.

 

[don_resqcapt19]

I'm not trying to over-think this, but assuming that the service mentioned in #1 is a bonded metal box, would it be compliant to replace a single PVC nipple with GRC? (Also assuming no concentric knockouts or other such rot; not that I would expect it when 4" pipes are in use.)

That would result in a violation of 310.10(H).

 

[Ponchik]

I am sure I am not seeing what you guys are seeing, but why the need to bond PVC raceway? The installation is all PVC raceway. The bonding is to ensure the metal locknut is bonded??
:?:?I am lost.

 

[zbang]

That would result in a violation of 310.10(H).

Are you thinking of (H)(3) "separate raceways" or another subsection? I don't see how that would apply. One could argue that (2) "Conductor characteristics" might, but I think that would be a stretch. Would (5) apply since the GRC is serving as the EGC? Otherwise, I'm not following (and don't have a 2014 code handy, only '08 and '11).

 

[augie47]

I am sure I am not seeing what you guys are seeing, but why the need to bond PVC raceway? The installation is all PVC raceway. The bonding is to ensure the metal locknut is bonded??
:?:?I am lost.

Install is PVC raceway but metallic wireway.
E/C was looking at options to using the grounded conductor in the wireway to bond since the panel is only a few feet away. I initially thought her could route (1) appropriately sized bonded jumper from the panelboard neutral bar to the wireway but then in reading 250.102(C) realized the jumper would need to be in each raceway thus 7 jumpers and terminations.

 

[don_resqcapt19]

Are you thinking of (H)(3) "separate raceways" or another subsection? I don't see how that would apply. One could argue that (2) "Conductor characteristics" might, but I think that would be a stretch. Would (5) apply since the GRC is serving as the EGC? Otherwise, I'm not following (and don't have a 2014 code handy, only '08 and '11).

It is not a stretch, all of the raceways of the parallel circuit must be of the same size and type, both (2) and (3) apply.
From the handbook commentary:

...Also, the three raceways are intended to have the same physical characteristics (e.g., three rigid aluminum conduits, three steel IMC conduits, three EMTs, or three nonmetallic conduits), not a mixture (e.g., two rigid aluminum conduits and one rigid steel conduit). ...