thinking this through

[caosesvida]

I have 5 disconnects, from one service with 5 meters. Going to five trailers.
1. feed in with paralell 500 copper and 350 neut.
2. tap grounded condutors to each meter
3. meters to trough, 2" nipple
4. trough to disconnects, 2" offsets
5. disconnects bonded.
6. not using bonding locknuts
7. disconnects combo of 200-100-150 amp.

The grounded conductor is bonded to the meter at the meter, then bonded to the disconnect. The trough has a grounding lug with #6 going to the ground rod.

Is my trough properly grounded/bonded to the system, through the disconnects and the 2" offset. I feel like I should run a bonding jumper from the disconnect to the trough for some reason. Having the trough bonded through the offsets should allow any current a return path, but it seems like a #6 from the disconnects to the trough and to the grounding electrode seems more thorough. OR does this lead to more paths for a ground fault to follow? thanks for any thoughts on this.

 

[augie47]

Re: thinking this through

If I am reading correctly, youe service conduits/conductors enter the wireway and you are tapped to your meters/disconnects. The trough (wireway)would need to be grounded. You mentioned no bonding locknuts, therefore the conduit system is not acting as the required ground. Parallel 500s would require a 2/0 for bonding the wireway. The most common method in these parts would be to install a stud kerney in the wireway and bond with your 350 neutral.

 

[George Stolz]

Re: thinking this through

First, look through 250.92 to be sure you're in compliance (as in, not relying on concentric knockouts to carry fault current, etc.)

Originally posted by caosesvida:
OR does this lead to more paths for a ground fault to follow? thanks for any thoughts on this.

Don't concern yourself with having too many paths for a ground fault. By Ohms law, the more paths you have the lower the overall resistance.

Do be concerned about multiple paths for neutral current. Limit it as much as practicable.

Gotta go to work now.

 

[eprice]

Re: thinking this through

The grounded conductor is bonded to the meter at the meter, then bonded to the disconnect. The trough has a grounding lug with #6 going to the ground rod.

If I am reading this right, your GEC is connected to the trough with no direct connection to the grounded conductor? This would be a violation of 250.24(A).

 

[caosesvida]

Re: thinking this through

yes eprice that is correct, I guess that is what didn't seem right. My grounded conductor is only conducting though the indivdual grouned conductors going from the meter ( which is bonded ) to the disconnects (which are bonded) so that would rely on the cans to connect the trough and the grounding electrode to the service. I will do the kernel to the trough off the 350, Another reason I like those polaris type connectors. thanks for the replies.