This is how I understand a res service is done. If the MBJ in the main panel is removed, I’d have to isolate grounds and neutrals correct?

[SomeRandomPerson]

One of the befits of the new 'emergency disconnect' provision is that you can keep the same install methodology (3 wire from meter to main panel, grounds and neutrals shared on main panel, GEC landed at main panel or meter location) when that outside breaker/disconnect is added in. This reduces the cost adder of an external disconnect.

-Jon

When does labeling come into the equation?


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[winnie]

When does labeling come into the equation?

Originally, the service equipment was _always_ the first OCPD and no labels were required.

Now you may have an 'emergency disconnect', and it may be a circuit breaker. But if it is labeled as the 'emergency disconnect' then the 'service equipment' can be downstream.

Jon

 

[SomeRandomPerson]

Originally, the service equipment was _always_ the first OCPD and no labels were required.

Now you may have an 'emergency disconnect', and it may be a circuit breaker. But if it is labeled as the 'emergency disconnect' then the 'service equipment' can be downstream.

Jon

Thanks for that Jon


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[newservice]

Here in Upstate NY National Grid does not allow anything in that kind of meter socket aka residential overhead 200a, besides the service conductors. Mass isn't any different as far as I know as New England and Mass are the other Grid territory besides Upstate NY.
Your underground water pipe, and/or the supplemental ground rod system, would be all connected at the service disconnect, which is the first place inside the residence that the service entrance conductors terminate. The entrance cable must terminate in a disconnect within a short distance of entering the structure. (short distance which I am still unsure exactly how far but I like to keep it about 4 feet or less.)
Additionally, if you have municipal water, as your diagram indicates, you only need one supplemental ground rod. The water meter connection on the side that goes to the underground water pipe is considered a mandatory ground, then, if the inside water piping is metalic, you jumper across the water meter to Bond the inside water piping.

 

[electrofelon]

Here in Upstate NY National Grid does not allow anything in that kind of meter socket aka residential overhead 200a, besides the service conductors. Mass isn't any different as far as I know as New England and Mass are the other Grid territory besides Upstate NY.
Your underground water pipe, and/or the supplemental ground rod system, would be all connected at the service disconnect, which is the first place inside the residence that the service entrance conductors terminate. The entrance cable must terminate in a disconnect within a short distance of entering the structure. (short distance which I am still unsure exactly how far but I like to keep it about 4 feet or less.)
Additionally, if you have municipal water, as your diagram indicates, you only need one supplemental ground rod. The water meter connection on the side that goes to the underground water pipe is considered a mandatory ground, then, if the inside water piping is metalic, you jumper across the water meter to Bond the inside water piping.

That is a common central NY myth. I was taught that when I was learning and believed it for years!

 

[newservice]

That is a common central NY myth. I was taught that when I was learning and believed it for years!

That you only need 1 rod if you have ug metal water pipe is a myth? Absent some other form of grounding grid, residential, that is how I read it. All the inspectors too. We use 2 if we have well water.

 

[petersonra]

That you only need 1 rod if you have ug metal water pipe is a myth? Absent some other form of grounding grid, residential, that is how I read it. All the inspectors too. We use 2 if we have well water.

The code is clear on this. Take a look at 250.53(A)(2).

(2) Supplemental Electrode Required. A single rod, pipe, or
plate electrode shall be supplemented by an additional electrode
of a type specified in 250.52(A)(2) through (A)(8).

It might not make much sense but it is what it is.

 

[infinity]

I agree, unless you're testing the rods to prove 25 ohms or less you must install two electrodes.

 

[Electromatic]

I hate to hijack a thread, but the last few posts regard something I've wondered for a while.
It seems to me that the underground water pipe (metal, 10', etc.) is a pipe electrode. It would need to be supplemented by an additional electrode. So wouldn't the water pipe and one ground rod be perfectly fine?

 

[electrofelon]

I hate to hijack a thread, but the last few posts regard something I've wondered for a while.
It seems to me that the underground water pipe (metal, 10', etc.) is a pipe electrode. It would need to be supplemented by an additional electrode. So wouldn't the water pipe and one ground rod be perfectly fine?

The section posted in post #87 seems to imply one, but you have to follow through and then go where that section tells you to go and read that. You will see two rods are required

 

[wwhitney]

I hate to hijack a thread, but the last few posts regard something I've wondered for a while.
It seems to me that the underground water pipe (metal, 10', etc.) is a pipe electrode. It would need to be supplemented by an additional electrode. So wouldn't the water pipe and one ground rod be perfectly fine?

In the context of Article 250, a "pipe" electrode is as described in 250.52(A)(5) "Rod and Pipe Electrodes" and would not include a 250.52(A)(1) "Metal Underground Water Pipe". 250.53(D)(2) specifies that a metal underground water pipe electrode have a supplemental electrode, and it references 250.53(A) on rod, pipe or plate electrodes. That makes it clear that if the 250.53(D)(2) electrode supplemental to the underground water pipe electrode is a rod, pipe, or plate electrode, it must itself have a supplemental electrode per 250.53(A)(2). And 250.53(A)(2) excludes 250.52(A)(1) electrodes for the supplemental electrode, so that supplemental electrode can't be the original underground water pipe electrode.

Cheers, Wayne
.

 

[LarryFine]

It seems to me that the underground water pipe (metal, 10', etc.) is a pipe electrode. It would need to be supplemented by an additional electrode. So wouldn't the water pipe and one ground rod be perfectly fine?

If you can prove the continuous water-pipe, and 25 ohms or less for the rod.

 

[Electromatic]

We've always driven two rods, but I have wondered about this. I suppose I can see the supplement to the supplement almost circular logic, but now I'm curious if that was the intention.
Couldn't one just get stuck in a big 250.53(A)(2) loop? I drive one rod. Oh, I have to supplement that with something. I'll drive one more single rod. Oh, I have to supplement that!!!.......

 

[infinity]

We've always driven two rods, but I have wondered about this. I suppose I can see the supplement to the supplement almost circular logic, but now I'm curious if that was the intention.
Couldn't one just get stuck in a big 250.53(A)(2) loop? I drive one rod. Oh, I have to supplement that with something. I'll drive one more single rod. Oh, I have to supplement that!!!.......

One rod tested to 25 ohms or less or two rods. Either one qualifies as an electrode.

 

[Electromatic]

Well, technically, wouldn't two rods be an electrode system?

 

[infinity]

Well, technically, wouldn't two rods be an electrode system?

Not really two rods are required to make one electrode unless a single rod tests at 25 ohms or less.

 

[wwhitney]

Couldn't one just get stuck in a big 250.53(A)(2) loop? I drive one rod. Oh, I have to supplement that with something. I'll drive one more single rod. Oh, I have to supplement that!!!.......

Fortunately no. Each ground rod needs a supplement (if not tested to under 25 ohms). With 2 rods, each one supplements the other. Done.

With a water pipe electrode, it needs a supplement. So you choose a ground rod. That needs a supplement, which is explicitly prohibited from being a water pipe electrode. So you add a second rod. Now each rod has a supplement, as does the water pipe electrode.

Cheers, Wayne

 

[Electromatic]

I get it. It just seems to me like a qualifying water pipe and one rod should be sufficient. If there were absolutely no other electrodes, one could drive two 8' rods or pipes and be okay. But if you have one 10' (water) pipe and one 8' rod or pipe, that's not good enough.

 

[newservice]

OK I have 1996 article 250-81 Grounding Electrode System,
" If available on the premises at each building or structure served, each item "(a)" through (d) below, and any made electrodes in accordance with Sections 250-83(c) and (d), shall be bonded together to form the grounding electrode system. "

a) Metal Underground Water Pipe.

A metal underground water pipe in direct contact with the earth for 10 ft (3.05 m) or more (including any metal well casing effectively bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or sections or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Continuity of the grounding path or the bonding connection to interior piping shall not rely on water meters or filtering devices and similar equipment. A metal underground water pipe shall be supplemented by an additional electrode of a type specified in Section 250-81 or in Section 250-83. The supplemental electrode shall be permitted to be bonded to the grounding electrode conductor, the grounded service-entrance conductor, the grounded service raceway, or any grounded service enclosure.

 

[infinity]

I get it. It just seems to me like a qualifying water pipe and one rod should be sufficient. If there were absolutely no other electrodes, one could drive two 8' rods or pipes and be okay. But if you have one 10' (water) pipe and one 8' rod or pipe, that's not good enough.

One rod with the water pipe is not good enough because in some places the metal water pipe is replaced with a nonmetallic pipe and then according to the NEC the single untested rod is not good enough.