Bonding and schedule 80 conduit

[wa5yom]

I replaced the OLD 100 AMP service with a new 200 AMP service. The original circuit wires to the breaker panel were not long enough to reach the new breaker panel.

So, we installed a j-box. The cirecuit wires run through schedule 80 conduit to the j-box and on to the breaker panel.

The schedule 80 is secured to the j-dox with metal lock nuts.

The nspector said we needed to bond the schedule 80 box.

This would make sence if the j-box was metal, unles the concern is that a wire could come in conact with the metal lock nut.

If so the bonding would be to the lock nut. At least that is how it appears to me.

Any thoughts?

 

[kwired]

use appropritately sized nylon string, attach one end to ground conductor and the other to the box. Use nylon bolt and nut. String and hardware must be green.

Conductors for old 100 amp service are large enough for the new 200 amp service?

 

[raider1]

Ask the inspector to cite the code reference for bonding of a non-metallic junction box.

Chris

 

[infinity]

Conductors for old 100 amp service are large enough for the new 200 amp service?

I think his box was for the branch circuits.

 

[wa5yom]

Correct...the box is for the branch circuits...

 

[infinity]

Correct...the box is for the branch circuits...

So what type of box, PVC? What type of cables are you extending and how long is the Sch 80 conduit?

 

[don_resqcapt19]

250.4(A)(2) would require that you bond the metal locknuts.

 

[wa5yom]

All the non-metalic is schedule 80.....

The schwedule 80 is length about 1 foot from the box to the breaker panel and about 4 foot from the box to the wall penetration.

Bonding the metal lock nuts was the only thing that I could think of...as i mentioned in my original post.

How would you suggest bonding the metal lock nuts?

 

[don_resqcapt19]

...

How would you suggest bonding the metal lock nuts?

I am not sure there is a way to do that. I would look for non-metallic locknuts or replace the male adapters with box adapters.

 

[Dennis Alwon]

250.4(A)(2) would require that you bond the metal locknuts.

Many multi gang non metallic switch boxes use metal clamps to hold the nm in place. I have never seen a provision to ground them. I don't think they are likely to be energized. 250.4 (A)(4)

 

[ptonsparky]

Many multi gang non metallic switch boxes use metal clamps to hold the nm in place. I have never seen a provision to ground them. I don't think they are likely to be energized. 250.4 (A)(4)

FWIW, I agree. Never ever had an inspector even suggest a locknut would require bonding when using non metallic jbox and pvc conduit.

 

[wa5yom]

Agree..it is highly unlikely that the metal lock nuts will ever be a problem.

I think the thought is..if a hot wire comes in contact with the lock nut there is no path to ground....

I see no way to ground the lock nuts.

So, the only solution is do dismantle the J-box, pull the wires out and use plastic lock nuts.

 

[wa5yom]

Potential solution is a T&B Series 3651 Bonding and Grounding Wedge.

Any thoughts on this solution?

 

[don_resqcapt19]

Many multi gang non metallic switch boxes use metal clamps to hold the nm in place. I have never seen a provision to ground them. I don't think they are likely to be energized. 250.4 (A)(4)

I cited the rule in 250.4(A)(2) and not (A)(4). These rules are independent and the one in (A)(2) does not contain the "likely to be energized" wording.

 

[hurk27]

I got one question:

What was the existing wiring method that is now run into this non-metallic box?

If it is a metallic raceway you would have no fault current path for ground faults.

 

[wa5yom]

A j-box is used since the original wires were not long enough to get to the new breaker panel.

Wire nuts are used to extend the lenght of the wires. Not all circuit wires were needed, so those wires dead end in the j-box...

The NM field wiring is under the house.....Schedule 80 penetrates the crawl space, so the field wiring path to the J-box is through schedule 80, then out of the j-box through schdule 80 and into the breaker panel.

 

[WIMaster]

Potential solution is a T&B Series 3651 Bonding and Grounding Wedge.

Any thoughts on this solution?

Sounds like a winner and the fastest/simplest route to resolving the issue with the AHJ.

 

[Twoskinsoneman]

I'm missing it... why can't a regular bonding bushing be used instead on the lock nut?

 

[WIMaster]

I'm missing it... why can't a regular bonding bushing be used instead on the lock nut?

The design intent of bonding bushings is that the set screw locks and bonds the bushing to the conduit or fitting it is attached to. In this case it would be PVC. Bonding bushings by design do not have to be tight to the locknut to work.
I understand your theory but the bushing would not be used as it is listed.
The wedge would be used as intended and can be installed without removing the wires from the raceways.

 

[Twoskinsoneman]

The design intent of bonding bushings is that the set screw locks and bonds the bushing to the conduit or fitting it is attached to. In this case it would be PVC. Bonding bushings by design do not have to be tight to the locknut to work.
I understand your theory but the bushing would not be used as it is listed.
The wedge would be used as intended and can be installed without removing the wires from the raceways.

Yeah I see what you mean. I was thinking of using it instead of the locking nut but I'm not sure if that is compliant. What about one of these dew-hickeys?

Seems you could land a EGC right on it