Objectionable current

[jdewitt37000]

Does article 250.142(B)(2) ex 2 allow 240.6 to be ignored or provide an exception to 240.6. I am having this discussion with someone whose knowledge of the code I have rarely questioned. This came up on set of plans that shows (4) services fed from a common gutter where the engineer shows a ground wire coming from the gutter to the meter enclosure (ME) and then down to the service disconnect (SD).

He says unequivocally 250.142(B)(2) ex 2 allows an exception to 240.6 at a service. I disagree, I believe it allows a grounding conductor from the load side of a service disconnect (SD) to either return from the SD through a raceway (or cable I suppose) and bond a meter enclosure if there is no other equipment grounding present at the enclosure (250.142(A). I don't believe it allows for the neutral bonded to the ME AND an equipment ground. from the load side of the disconnect.

When I mentioned 110.3(B) does not allow us to install an insulated neutral lug in a ME that did not come that way from the factory so I could comply with 240.6 he still said it meets code.

I don't understand what I am missing here.

 

[jdewitt37000]

Does article 250.142(B)(2) ex 2 allow 240.6 to be ignored or provide an exception to 240.6. I am having this discussion with someone whose knowledge of the code I have rarely questioned. This came up on set of plans that shows (4) services fed from a common gutter where the engineer shows a ground wire coming from the gutter to the meter enclosure (ME) and then down to the service disconnect (SD).

He says unequivocally 250.142(B)(2) ex 2 allows an exception to 240.6 at a service. I disagree, I believe it allows a grounding conductor from the load side of a service disconnect (SD) to either return from the SD through a raceway (or cable I suppose) and bond a meter enclosure if there is no other equipment grounding present at the enclosure (250.142(A). I don't believe it allows for the neutral bonded to the ME AND an equipment ground. from the load side of the disconnect.

When I mentioned 110.3(B) does not allow us to install an insulated neutral lug in a ME that did not come that way from the factory so I could comply with 240.6 he still said it meets code.

I don't understand what I am missing here.

The other thing I think it allows for is situations where you have a service disconnect feeding a gutter which then goes to tenant services but I still don't see how it is an exception to 240.6. I still think to do this the neutral would need to be insulated from the ME.

 

[infinity]

Short answer is that a wire type conductor is not permitted to be in parallel with the neutral ahead of the service disconnect.

Welcome to the Forum.

 

[Dennis Alwon]

Tell us how the neutrals are connected. Are the neutrals and equipment grounding conductor's both in parallel

 

[jdewitt37000]

Well according to 250.148 a grounding conductor has to be connected to every enclosure there is a termination or splice in. I attached the riser from the project. I should have done that with the post but didn't realize it was an option.

 

[infinity]

Well according to 250.148 a grounding conductor has to be connected to every enclosure there is a termination or splice in. I attached the riser from the project. I should have done that with the post but didn't realize it was an option.

I agree with what is in the red ballons. EGC's are not used on the line side of the servcie disconnect. All metal parts and equipment is bonded directly to the neutral.

 

[jdewitt37000]

Short answer is that a wire type conductor is not permitted to be in parallel with the neutral ahead of the service disconnect.

Welcome to the Forum.

I completely agree but the person I am speaking to does not he insists that it is compliant. I don't mind being wrong I practice that daily what is frustrating me is that he won't explain his position.

 

[infinity]

I completely agree but the person I am speaking to does not he insists that it is compliant. I don't mind being wrong I practice that daily what is frustrating me is that he won't explain his position.

Good luck with this person. It's obvious that they do not grasp the concept of bonding everything to the neutral ahead of the service disconnect. He could try and explain his position but not knowing how the system is actually supposed to work will make his explanation nonsensical.

 

[jdewitt37000]

I just got another email from him and he stated that he gave me the wrong reference that he should have given me 250.142(A) which still does not make any sense. It still ignores 250.6.

 

[infinity]

250.142 Use of Grounded Circuit Conductor for Grounding Equipment.
(A) Supply-Side Equipment. A grounded circuit conductor shall be permitted to ground non–current-carrying metal parts of equipment, raceways, and other enclosures at any of the following locations:
(1) On the supply side or within the enclosure of the ac service-disconnecting means
(2) On the supply side or within the enclosure of the main disconnecting means for separate buildings as provided in 250.32(B)
(3) On the supply side or within the enclosure of the main disconnecting means or overcurrent devices of a separately derived system where permitted by 250.30(A)(1)

Sounds like it's telling you that you use the neutral to bond metal parts, raceways etc ahead of the service disconnect.

 

[jdewitt37000]

Sounds like it's telling you that you use the neutral to bond metal parts, raceways etc ahead of the service disconnect.

I agree with your comment but that still does not explain why it is ok (per the code guru i am discussing this with) to have an EGC in parallel to grounded conductor between a meter socket and a gutter. If someone pulled that EGC off in the gutter it would be live with an unbalanced current and could easily kill them.

My reason for this post is that I am trying to make sure that I am not missing something. I am to the point that I think he has not really carefully read my notes on the plans and that he may be missing some of the information. I am going to call him tomorrow and go over it but I am pretty confused right now.

 

[Tulsa Electrician]

I looked at your diagram.
Look at where the GEC are ran to.
Since there are separate meters and service disconnects. How do you ground the service netutal in the disc.
Now food for thought. What if the so called egc is A GEC insulated ran through the meter enclosure to the disc to MBJ.
Granted I would run this out side however it showed ran inside.
Look and check the size you will notice it is sized for GEC rather than egc.
If you use EMT or other metlic raceway must use grd lockouts ECT.
You can use PVC if allowed in your area and allow the grounded conductor to ground meter and run GEC straight through into disc to MBJ. This way you avoid unwanted currents.
Now your GEC can go to aux gutter and land on the GEC buss/ bar and ground aux gutter as well.
Or run GEc to disc outside and ground through from outside GEC bar. Then you use EMT/ metlic and use grd lockouts. Then no egc required to run through meter. I would still look at PVC option depending on area of use and ahj.
I really believe the intent there was for that conductor in question be an GEC And be used like an SSBJ would as an egc as well.
Take another look

 

[Tulsa Electrician]

There's a reason the 3/0 goes to aux gutter

 

[jdewitt37000]

I looked at your diagram.
Look at where the GEC are ran to.
Since there are separate meters and service disconnects. How do you ground the service netutal in the disc.
Now food for thought. What if the so called egc is A GEC insulated ran through the meter enclosure to the disc to MBJ.
Granted I would run this out side however it showed ran inside.
Look and check the size you will notice it is sized for GEC rather than egc.
If you use EMT or other metlic raceway must use grd lockouts ECT.
You can use PVC if allowed in your area and allow the grounded conductor to ground meter and run GEC straight through into disc to MBJ. This way you avoid unwanted currents.
Now your GEC can go to aux gutter and land on the GEC buss/ bar and ground aux gutter as well.
Or run GEc to disc outside and ground through from outside GEC bar. Then you use EMT/ metlic and use grd lockouts. Then no egc required to run through meter. I would still look at PVC option depending on area of use and ahj.
I really believe the intent there was for that conductor in question be an GEC And be used like an SSBJ would as an egc as well.
Take another look

We did use PVC for the nipples between the enclosures. If you bond the GEC with the neutrals in the gutter you can use them to bond your meter sockets so you don't need an EGC per 250.142(A)

I think I have been misunderstanding the intent of the engineer is (and you clued me in to this). The riser does not actually show the GEC bonded to the grounded (neutral) conductors in the gutter. If the neutrals are not bonded to the gutter and what I thought were EGCS were actually GECs coming from the meter socket back to the primary GEC which is bonded to the gutter then this riser makes sense. It is complying with 250.64(D)(1) not 250.64(D)(3). If you compare it to Mike Holt's diagrams it is wired like the one on the left (see my upload) but the busbar is located in the gutter not under the disconnects like Mike illustration. I am going to email the engineer tomorrow and ask him if this is his intent.

 

[infinity]

What does a GEC have to do with an EGC ahead of the service disconnect?

 

[Tulsa Electrician]

Look forward to his reply.
One item to take into account if the wire in question is an GEC. Some utility will not allow it to pass through meter. In that case a hole in bottom of gutter run external to disc with drip loop go into bottom of disc.
Another item would 60% fill on the PVC. Now you do not not need to count that conductor. The GEC is allowed to run outside the raceway in that case.
If indeed it's a egc than it has to be routed with the other conductors and I would say bad design as you will have a objectional current on the
egc as you stated.
I picked up on the size as it is different for the service conductors versus feeder. I call these red flags and look closer. Looking at the available fault current I seen no reason to up size plus you full size neutrals.
Now for the color of the conductor if an GEC. I use black not green or green tape. I mention this due to you a #6. Now one look and we know it's not an egc. No confusion as I don't believe the GEC has a color requirement per NEC.

 

[Tulsa Electrician]

Oh ya if you run external watch you protection rule on that #6, #4 would fix.