Service entrance conductors - grounding conductor

[jap]

Correct but a disconnect without overcurrent protection would be something other than a service disconnect. An emergency disconne maybe. If you didnt have the overcurrent protection
You would simply be disconnecting the Service Conductors and you wouldnt be pulling an isolated grounded conductor and an EGC from that point. I may be explaining myself incorrectly.
Jap,

 

[electrofelon]

Correct but a disconnect without overcurrent protection would be something other than a service disconnect. An emergency disconne maybe. If you didnt have the overcurrent protection
You would simply be disconnecting the Service Conductors and you wouldnt be pulling an isolated grounded conductor and an EGC from that point. I may be explaining myself incorrectly.
Jap,

I think we agree. I would just add that a disconnect without OCPD could be a service disconnect if the OCPD is immediately adjacent to it, in which case yes you would separate the neuter and EGC after the disconnect only.

 

[jap]

I think we agree. I would just add that a disconnect without OCPD could be a service disconnect if the OCPD is immediately adjacent to it, in which case yes you would separate the neuter and EGC after the disconnect only.

I think so too, but, If you have a Service Disconnect (without OCPD) the separation of the neutral and EGC would take place after the OCPD not after the "Disconnect" unless the Service Disconnect and the OCPD happen to be one in the same.

Jap>

 

[electrofelon]

I think so too, but, If you have a Service Disconnect (without OCPD) the separation of the neutral and EGC would take place after the OCPD not after the "Disconnect" unless the Service Disconnect and the OCPD happen to be one in the same.

Jap>

That is incorrect. See the code references in post number 20

 

[jap]

That is incorrect. See the code references in post number 20

I don't see a 250.24(A)(5) in the 2023, but, that section seems to be talking about the Grounding Electrode Conductor not the Equipment Grounding Conductor.

We don't pull an EGC on the load side of an Emergency Disconnect since they are still Service Conductors.
Why would we pull an EGC after a disconnect that has no OCPD incorporated into it.?

To me the would be like pulling an EGC from the Load Side of a Meterbase to the Service Disconnect which we do not do.

The Grounded Conductor serves as the Fault return path at that point.


Jap>

 

[wwhitney]

Why would we pull an EGC after a disconnect that has no OCPD incorporated into it.?

See 250.24(C). It specifies that the MBJ is in the service disconnect enclosure, not the service OCPD enclosure. And the EGC originates in the enclosure with the MBJ.

Cheers, Wayne

 

[jap]

See 250.24(C). It specifies that the MBJ is in the service disconnect enclosure, not the service OCPD enclosure. And the EGC originates in the enclosure with the MBJ.

Cheers, Wayne

The bonding jumper has to be in place to connect Equipment Grounding Conductors to the Grounded Conductor for fault clearing purpose that's a given, but, you're saying you would pull an EGC along with the Grounded Conductor from the load side of a Non Fused Disconnect fed off of a utility Transformer to the first means of Overcurrent Protection?

There used to be a rule and believe there still is that the the grounded conductor was to be the sole return path at that point of the system.
That's also why we don't pull an EGC from a utility padmount inside to an MDP.

To me, a Non Fused disconnect does not change the fact that you are still dealing with Service Conductors and I have never pulled in an EGC with Service Conductors.

We did one time early not knowing any better from a padmount Xfmr to a MDP inside and the Power Company cut them off at the stub up.


Jap>

 

[wwhitney]

I don't see a 250.24(A)(5) in the 2023

It became 250.24(B) in the 2023 NEC: "A grounded conductor shall not be connected to normally non-current-carrying metal parts of equipment, to equipment grounding conductor(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article."

Note it says load side of the service disconnecting means. So in the case that the service OCPD is in a separate enclosure immediately adjacent to the service disconnecting means, but on the load side of it, you may not use the grounded conductor for bonding in the service OCPD enclosure. That's because the service disconnect enclosure has the MBJ, so you run an EGC from the service disconnect enclosure to the service OCPD enclosure.

Cheers, Wayne

 

[LarryFine]

Feeder conductors include an EGC; service conductors do not.

 

[jap]

It became 250.24(B) in the 2023 NEC: "A grounded conductor shall not be connected to normally non-current-carrying metal parts of equipment, to equipment grounding conductor(s), or be reconnected to ground on the load side of the service disconnecting means except as otherwise permitted in this article."

Note it says load side of the service disconnecting means. So in the case that the service OCPD is in a separate enclosure immediately adjacent to the service disconnecting means, but on the load side of it, you may not use the grounded conductor for bonding in the service OCPD enclosure. That's because the service disconnect enclosure has the MBJ, so you run a separate EGC from the service disconnect enclosure to the service OCPD enclosure.

Cheers, Wayne

Feeder conductors include an EGC; service conductors do not.

That's my point.
You can't have a Feeder or an EGC if you don't first have an OCPD ahead of the conductors.
You don't have an OCPD ahead of the conductors in a Non Fused Service Disconnect fed off the load side of a utility Transformer.

If you install the bonding jumper in the Service Disconnect, (which you are required to do), are you then not creating parallel return paths from the OCPD that's located immediately adjacent to it if you install an EGC along with the Grounded Conductor between those 2 points?

Jap>

 

[wwhitney]

Feeder conductors include an EGC; service conductors do not.

In this unusual scenario where the service OCPD is in a separate enclosure immediately adjacent to the service disconnecting means, it is unclear how to label the conductors between the two enclosures. They are not service conductors, as that definition says "The conductors from the service point to the service disconnecting means."

As to whether they are afeeder, that definition says "All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device". When the service equipment comprises multiple enclosures, it's unclear to me if that definition covers the conductors within the service equipment, or if a feeder would only begin on the load side of the service OCPD.

At least it's fairly clear that the service OCPD is service equipment: "The necessary equipment, usually consisting of a circuit breaker(s) or switch(es) and fuse(s) and their accessories, connected to the load end of service conductors to a building or other structure, or an otherwise designated area,
and intended to constitute the main control and cutoff of the supply." Given that the definition reference OCPD types, and covers not just "cutoff" of the supply but also "control" of the supply, the service OCPD is service equipment.

Cheers, Wayne

 

[wwhitney]

You can't have a Feeder . . . if you don't first have an OCPD ahead of the conductors.

Maybe yes, maybe no, see the previous post.

You can't have a . . .EGC if you don't first have an OCPD ahead of the conductors.

Incorrect, this case we are discussing is the exception to that "rule".

If you install the bonding jumper in the Service Disconnect, (which you are required to do), are you then not creating parallel return paths from the OCPD that's located immediately adjacent to it if you install an EGC along with the Grounded Conductor between those 2 points?

No, because 2023 NEC 250.64(B) prohibits using the grounded conductor to bonded the enclosure of that service OCPD downstream of the unfused Service Disconnect, so the enclosure will only be bonded to the EGC. No parallel paths are created.

Cheers, Wayne

 

[wwhitney]

P.S. The idea that the MBJ must be in the service disconnect is a semi-arbitrary choice the NEC made. For services with multiple disconnects, some aspects of the grounding and bonding would be simpler if the NEC permitted a single common MBJ in an enclosure upstream of all the disconnects. The point is that the location of the MBJ determines the point at which you stop using the grounded conductor for bonding and start using a separate EGC for bonding.

Cheers, Wayne

 

[LarryFine]

In this unusual scenario where the service OCPD is in a separate enclosure immediately adjacent to the service disconnecting means, it is unclear how to label the conductors between the two enclosures. They are not service conductors, as that definition says "The conductors from the service point to the service disconnecting means."

I tend to see and treat the two as if they were still within a single enclosure.

If you have a metal nipple between the two, the enclosures are bonded, EGC or not.

The premises EGC system can start in the OCP enclosure rather than in the switch.

So, is the nipple a service nipple or a feeder nipple, and what the conductors in it?

To me, they are feeders, as the switch is the service disconnect, not the OCPD.

I think.

 

[jap]

I tend to see and treat the two as if they were still within a single enclosure.

If you have a metal nipple between the two, the enclosures are bonded, EGC or not.

The premises EGC system can start in the OCP enclosure rather than in the switch.

So, is the nipple a service nipple or a feeder nipple, and what the conductors in it?

To me, they are feeders, as the switch is the service disconnect, not the OCPD.

I think.

I'm thinking the same thing on a lot of this,,, we must be related,,,,, Lol !!!

Jap>

 

[wwhitney]

I tend to see and treat the two as if they were still within a single enclosure.

I guess that depends on the interpretation of "immediately adjacent". If the two enclosures literally touching, with e.g. a chase nipple between then, that seems plausible. Just pretend it's one big enclosure.

If you have a metal nipple between the two, the enclosures are bonded, EGC or not.

Certainly. But if that metal nipple means the two enclosures have an airspace between them, I think the "treat them as one enclosure" idea can no longer apply. And so you have to parse out which of the things we are used to seeing in a common service disconnect/OCPD enclosure belong in the service disconnect enclosure, and which belong in the OCPD enclosure. Fortunately 250.24 spells it out for us.

The premises EGC system can start in the OCP enclosure rather than in the switch.

Negative, see 250.24, the MBJ goes in the disconnect enclosure, so the EGC system starts there.

So, is the nipple a service nipple or a feeder nipple, and what the conductors in it?

The conductors are not service conductors, per post #31. They may be feeders, or they may be some conductors the NEC doesn't define a name for.

To me, they are feeders, as the switch is the service disconnect, not the OCPD.

That statement, post #29, and your earlier statement that the "The premises EGC system can start in the OCP enclosure" are logically inconsistent. All three of the statements can't be true; that would be a contradiction.

Cheers, Wayne

 

[LarryFine]

Negative, see 250.24, the MBJ goes in the disconnect enclosure, so the EGC system starts there.

The metallic nipple can still serve as the premises EGC between them.

And, the neutral must never be bonded in or to the OCPD enclosure.

The OCPD has no effect on the transition between service and feeder.

All correct?

 

[wwhitney]

The metallic nipple can still serve as the premises EGC between them.

And, the neutral must never be bonded in or to the OCPD enclosure.

Sure

The OCPD has no effect on the transition between service and feeder.

I think that's a bit ambiguous, given the definition of "feeder" (see post #31). Does "between the service equipment" and the branch-circuit OCPD mean on the load side of all the service equipment, or on the load side of at least some of the service equipment? In the former case, the conductors between the service disconnect and service OCPD are neither service conductors nor a feeder, and I disagree with the quoted statement. In the latter case, they are a feeder, and I agree with the quoted statement.

Cheers, Wayne

 

[jap]

I don't think I've ever installed a new Service where the OCPD wasn't incorporated into the Service Disconnecting means.

I think I'll just keep doing that.


Jap>

 

[suemarkp]

One way that happens is to install a manual transfer switch that has no overcurrent protection. Put it on the line side of the main panel, and install the main panel with main breaker immediately adjacent to the MTS.