service grounding

[hhsting]

Below I have two service grounding

details. Which detail complies with NEC 2017 Article 250.64(D) detail 1 or detail 2?

 

[infinity]

The drawing on the left has all of the electrodes interconnected?

 

[hhsting]

The drawing on the left has all of the electrodes interconnected?

Yes

 

[don_resqcapt19]

the one on the left is (D)(1) and the one on the right is (D)(2)

 

[infinity]

Yes

Then Don gave you the correct answer.

 

[Elect117]

They both work but my concern would be with access / accessibility (250.68(A)) where the service panels or distribution sections could be locked by the tenets or they could be in separate rooms. One of them would not have access to all of the grounding electrode or bonding jumper connections. I don't know if that meets the definition of accessible though. Bolt cutters could fix that.

 

[wwhitney]

The one on the right seems a bit silly, there's no reason to have multiple bonding jumpers/GECs going into each panel.

It seems to me the difference between (D)(1) and (D)(2) could be expressed by dividing up space into "the region around the service panels" and "the region around the grounding electrodes" (all of which need to be interconnected, typically by bonding jumpers). Then in (D)(1) there is only a single GEC going between the two regions, and that GEC gets tapped at each panel. While in (D)(2) there is one GEC per panel that goes between the two regions.

Cheers, Wayne

 

[wwhitney]

Here's my version of the difference between (D)(1) and (D)(2). Apologies for the poor quality, didn't feel like redrawing from scratch.

Cheers, Wayne

 

[infinity]

The one on the right seems a bit silly, there's no reason to have multiple bonding jumpers/GECs going into each panel.

I agree there are better ways to do it but the method in 2 of the OP is code compliant even if it ends up being a bit of a mess.

 

[wwhitney]

I agree there are better ways to do it but the method in 2 of the OP is code compliant even if it ends up being a bit of a mess.

OK. But bringing each electrode to one panel suffices to interconnect them. The other panel can just get one GEC to one electrode. So 4 wires instead of 6 wires.

Cheers, Wayne

 

[augie47]

agree with others. if he conductors are properly sized, either is permissible.

 

[hhsting]

The one on the right seems a bit silly, there's no reason to have multiple bonding jumpers/GECs going into each panel.

It seems to me the difference between (D)(1) and (D)(2) could be expressed by dividing up space into "the region around the service panels" and "the region around the grounding electrodes" (all of which need to be interconnected, typically by bonding jumpers). Then in (D)(1) there is only a single GEC going between the two regions, and that GEC gets tapped at each panel. While in (D)(2) there is one GEC per panel that goes between the two regions.

Cheers, Wayne

In my post to the right their is one GEC going from each service disco to building grounding electrode system.

The building grounding electrode system node is at each ground bus bar inside each service discos. So the one GEC is the ground bus itself.

 

[wwhitney]

In my post to the right their is one GEC going from each service disco to building grounding electrode system.

Your drawing (2) appears to have one GEC per electrode per service disconnect. That is excessive.

If you tie the electrodes together separately with bonding jumpers, one GEC per service disconnect is sufficient for (D)(2). That GEC can go to any electrode. [Although if the electrodes have different required size bonding jumper/GECs, you have to be careful about the GEC sizing and base it on the largest of the required sizes, rather than on the size for the electrode the GEC runs to.]

If you don't separately tie the electrodes together, it would suffice to run one GEC/bonding jumper per electrode to one of the service panels, which would tie the electrodes together. Then for the other panel(s) (just one in your example), the previous paragraph would apply.

Cheers, Wayne

P.S. If the two or more service disconnects have different size SECs supplying them, then there's opportunity for further complexity as far as GEC/bonding jumper sizing. But the principle is simple enough: for any given electrode type, and any particular ungrounded conductor size supplying a service panel, there is a required minimum GEC/bonding jumper size. The conductive path from that electrode to that service panel must consist of conductors that are all at least that minimum size.

 

[don_resqcapt19]

They both work but my concern would be with access / accessibility (250.68(A)) where the service panels or distribution sections could be locked by the tenets or they could be in separate rooms. One of them would not have access to all of the grounding electrode or bonding jumper connections. I don't know if that meets the definition of accessible though. Bolt cutters could fix that.

The connections are only required to be accessible ....not readily accessible.

 

[infinity]

In my post to the right their is one GEC going from each service disco to building grounding electrode system.

The building grounding electrode system node is at each ground bus bar inside each service discos. So the one GEC is the ground bus itself.

Not sure what this means but the second graphic has three electrodes and six GEC's. Are you saying that it not accurate?

 

[hhsting]

Not sure what this means but the second graphic has three electrodes and six GEC's. Are you saying that it not accurate?

I am saying that complies with 250.64(D)(2)

 

[hhsting]

Your drawing (2) appears to have one GEC per electrode per service disconnect. That is excessive.

If you tie the electrodes together separately with bonding jumpers, one GEC per service disconnect is sufficient for (D)(2). That GEC can go to any electrode. [Although if the electrodes have different required size bonding jumper/GECs, you have to be careful about the GEC sizing and base it on the largest of the required sizes, rather than on the size for the electrode the GEC runs to.]

If you don't separately tie the electrodes together, it would suffice to run one GEC/bonding jumper per electrode to one of the service panels, which would tie the electrodes together. Then for the other panel(s) (just one in your example), the previous paragraph would apply.

Cheers, Wayne

P.S. If the two or more service disconnects have different size SECs supplying them, then there's opportunity for further complexity as far as GEC/bonding jumper sizing. But the principle is simple enough: for any given electrode type, and any particular ungrounded conductor size supplying a service panel, there is a required minimum GEC/bonding jumper size. The conductive path from that electrode to that service panel must consist of conductors that are all at least that minimum size.

Post #1 picture#2 to the right also complies with NEC 2017 Article 250.64(D)(2). Why do all this? You know i am reviewer and cannot tell them what you just said as long as it complies nec 2017 article 250.64(d)(2)

 

[hhsting]

I agree there are better ways to do it but the method in 2 of the OP is code compliant even if it ends up being a bit of a mess.

I dont see how method 2 is code compliant? Can you elaborate?


Sent from my iPhone using Tapatalk

 

[hhsting]

Your drawing (2) appears to have one GEC per electrode per service disconnect. That is excessive.

If you tie the electrodes together separately with bonding jumpers, one GEC per service disconnect is sufficient for (D)(2). That GEC can go to any electrode. [Although if the electrodes have different required size bonding jumper/GECs, you have to be careful about the GEC sizing and base it on the largest of the required sizes, rather than on the size for the electrode the GEC runs to.]

If you don't separately tie the electrodes together, it would suffice to run one GEC/bonding jumper per electrode to one of the service panels, which would tie the electrodes together. Then for the other panel(s) (just one in your example), the previous paragraph would apply.

Cheers, Wayne

P.S. If the two or more service disconnects have different size SECs supplying them, then there's opportunity for further complexity as far as GEC/bonding jumper sizing. But the principle is simple enough: for any given electrode type, and any particular ungrounded conductor size supplying a service panel, there is a required minimum GEC/bonding jumper size. The conductive path from that electrode to that service panel must consist of conductors that are all at least that minimum size.

If I tie grounding electrodes together with bonding jumper then what size bonding jumpers i need? I have 3/0 awg copper into each service disco

Also lets say i bring one GEC per electrode to one service disco and run one gec from another service disco one of the grounding electrodes then what size grounding electrodes i need from each service disco?

 

[infinity]

I dont see how method 2 is code compliant? Can you elaborate?

I am saying that complies with 250.64(D)(2)

I agree there are better ways to do it but the method in 2 of the OP is code compliant even if it ends up being a bit of a mess.

I already stated that the second method is code complaint. You've stated that you're a plan reviewer so you either say it is

code complaint or it isn't. Several others have already stated that is is code compliant. Why would it not be code compliant?

agree with others. if he conductors are properly sized, either is permissible.