GEC termination at CT cabinet

[rojay]

Can a grounding electrode conductor terminate to a CT cabinet enclosure where the service neutral is not bonded to the enclosure by a conductor type main bonding jumper?

 

[electrofelon]

Can a grounding electrode conductor terminate to a CT cabinet enclosure where the service neutral is not bonded to the enclosure by a conductor type main bonding jumper?

I would say no. Sorry I'm a bit lazy and not going to give you the exact code section, but the GEC must land to the grounded conductor, or the same terminal or bus that the grounded conductor is landed on in the service equipment. The one exception would be the "GEC busbar" which I guess you could put in the CT cabinet, but that would be weird.

 

[electrofelon]

See 250.64{D)(1)(3) and 250.64(F)(3) for the busbar methods.

 

[rojay]

I would say no. Sorry I'm a bit lazy and not going to give you the exact code section, but the GEC must land to the grounded conductor, or the same terminal or bus that the grounded conductor is landed on in the service equipment. The one exception would be the "GEC busbar" which I guess you could put in the CT cabinet, but that would be weird.

Thanks for the feedback. I was thinking 250.24(A) was the deal breaker for landing the GEC to the CT cabinet without a main bonding jumper. Around these parts none of the CT cabinets come factory bonded. Usually just a two position lug bolted to the side of the cabinet (where I’ve seen most guys land their ground rod conductor).

 

[hillbilly1]

Your utility may not allow it too, Georgia Power will not allow any of your grounds in their CT cabinet. They say they do their own bonding.

 

[electrofelon]

Thanks for the feedback. I was thinking 250.24(A) was the deal breaker for landing the GEC to the CT cabinet without a main bonding jumper. Around these parts none of the CT cabinets come factory bonded. Usually just a two position lug bolted to the side of the cabinet (where I’ve seen most guys land their ground rod conductor).

Right. But of you dig a little deeper, you find there is an exception to the rule in 250.24(A). The layout and logic of the code isn't great here. My first code reference allows the GEC(s) to terminate to a bus bar or just be tapped and then " grounding electrode conductor taps" to extend to each service disconnect (where there are multiple service disconnects). I was just saying you could in theory have you GEC busbar or tap in the cabinet, but no you could use the cabinet itself as the as the path between the GECs and GEC taps. Some AHJ's would consider the CT cabinet not accessible and your POCO could whine about it. Like I said, it would be weird and not a good way to do it. . You could mount a GEC busbar next to the CT cabinet.

 

[electrofelon]

Your utility may not allow it too, Georgia Power will not allow any of your grounds in their CT cabinet. They say they do their own bonding.

Seattle city light specifically does not allow the CT cabinet to be bonded directly to the neutral conductor. You must run a bonding jumper back to the service disconnect(s).

 

[rojay]

Seattle city light specifically does not allow the CT cabinet to be bonded directly to the neutral conductor. You must run a bonding jumper back to the service disconnect(s).

Have you had any issues with inspectors allowing the use of RMC or IMC between the unbonded CT & service disconnect enclosures as a type of “supply side bonding jumper?” I was thinking with grounding bushings w/ correctly sized bonding jumpers on both ends there shouldn’t be a problem.

 

[electrofelon]

Have you had any issues with inspectors allowing the use of RMC or IMC between the unbonded CT & service disconnect enclosures as a type of “supply side bonding jumper?” I was thinking with grounding bushings w/ correctly sized bonding jumpers on both ends there shouldn’t be a problem.

I don't see an issue as long as you use "service bonding" methods on both ends of the raceway. I recall someone saying you can't do that but I can't remember what the argument was.

 

[jaggedben]

Can a grounding electrode conductor terminate to a CT cabinet enclosure where the service neutral is not bonded to the enclosure by a conductor type main bonding jumper?

Yes, but...

The neutral can be bonded to the enclosure any way you want. And a main bonding jumper is by definition at the service disconnect, so if your CT cabinet is on the supply side of the service disconnect, you don't have a main bonding jumper there. But this is all irrelevant to whether your allowed to connect a GEC there.

Per the NEC, the GEC can be connected to the neutral at or on on the supply side of the service disconnect. See 250.24(A)(1). However, note that section requires an 'accessible point' and many will argue that once the utility seals a CT cabinet it's not accessible.

On top of this, many utilities will have their own rule against it.

So it is basically the utility and not the NEC that usually prohibits you from doing this. The NEC does not care.

 

[jaggedben]

Thanks for the feedback. I was thinking 250.24(A) was the deal breaker for landing the GEC to the CT cabinet without a main bonding jumper.

Actually that section says you can do it. But see above.

Around these parts none of the CT cabinets come factory bonded. Usually just a two position lug bolted to the side of the cabinet (where I’ve seen most guys land their ground rod conductor).

Assuming your service disconnect comes after the CT cabinet, you have to bond the CT cabinet to the grounded conductor (neutral). But if field installed it would be a supply-side bonding jumper, not a main bonding jumper. And it's required whether you land the GEC there or not. See 250.92.

 

[electrofelon]

Actually that section says you can do it. But see above.


Assuming your service disconnect comes after the CT cabinet, you have to bond the CT cabinet to the grounded conductor (neutral). But if field installed it would be a supply-side bonding jumper, not a main bonding jumper. And it's required whether you land the GEC there or not. See 250.92.

The way I read 250.24, the GEC must terminate directly to the grounded conductor, not to something that is connected to the grounded conductor - or at least I think that is what they mean.

 

[rojay]

Actually that section says you can do it. But see above.


Assuming your service disconnect comes after the CT cabinet, you have to bond the CT cabinet to the grounded conductor (neutral). But if field installed it would be a supply-side bonding jumper, not a main bonding jumper. And it's required whether you land the GEC there or not. See 250.92.

I think I’m clear on the GEC to neutral connection point. On to the service bonding that 250.92 calls out- I understand that 250.80 requires that all metal parts be bonded to the service neutral. The question is whether that needs to be a direct connection or not? Can the CT cabinet be bonded to the service neutral via metal raceways & grounding bushings & bonding jumpers at both ends?

 

[electrofelon]

I find the

I think I’m clear on the GEC to neutral connection point. On to the service bonding that 250.92 calls out- I understand that 250.80 requires that all metal parts be bonded to the service neutral. The question is whether that needs to be a direct connection or not? Can the CT cabinet be bonded to the service neutral via metal raceways & grounding bushings & bonding jumpers at both ends?

I don't see anything prohibiting that. A supply side cabinet must be bonded to the grounded conductor, but I don't see anything saying that connection must be "done right there" vs running vs running a bonding jumper and hitting the grounded conductor somewhere else. But to be clear, I still say you can't land the GEC to the cabinet. Is there or a neutral bus in the cabinet or are the neutrals run right thru?

 

[rojay]

I find the
I don't see anything prohibiting that. A supply side cabinet must be bonded to the grounded conductor, but I don't see anything saying that connection must be "done right there" vs running vs running a bonding jumper and hitting the grounded conductor somewhere else. But to be clear, I still say you can't land the GEC to the cabinet. Is there or a neutral bus in the cabinet or are the neutrals run right thru?

Agreed regarding the GEC. There is a neutral bus in the cabinet

 

[jaggedben]

I think I’m clear on the GEC to neutral connection point. On to the service bonding that 250.92 calls out- I understand that 250.80 requires that all metal parts be bonded to the service neutral. The question is whether that needs to be a direct connection or not? Can the CT cabinet be bonded to the service neutral via metal raceways & grounding bushings & bonding jumpers at both ends?

Yes, if it's something permitted in 230.92(B). Actually just replacing locknuts with bonding type locknuts is sufficient if you don't have reducing washers or eccentric or concentric knockouts.

I agree that you could also run a supply-side bonding jumper to the cabinet from somewhere else, although the code isn't very explicit about that.

 

[electrofelon]

Agreed regarding the GEC. There is a neutral bus in the cabinet

Why not just connect the GEC to the neutral bus?

 

[rojay]

Why not just connect the GEC to the neutral bus?

I’ll have to see if the neutral lugs are rated for multiple conductors. That may be an option, or another trip to the supply house may be in order.

 

[electrofelon]

I’ll have to see if the neutral lugs are rated for multiple conductors. That may be an option, or another trip to the supply house may be in order.

Not sure what your mounting bases are like, but ones we use usually have 1-3/4 OC NEMA standard studs so should be real easy to swap out to a different lig with more ports.

 

[ggunn]

Code says that the grounded (usually neutral) conductor must be bonded to a supply side CT enclosure, and most (all?) of the POCOs I have dealt with do not have a grounding conductor coming out of their CT can. They want a grounded to grounding conductor bond at the first disconnecting means with a GEC to a ground rod which is the point of origin for the EGC.