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Joined: Jul 2004
Posts: 9,923
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G
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The argument was about neutral current flowing through the metal nipple behind the panel to the meter can. They did not want to admit, that happens no matter what if you have a metal raceway and a bonded ground to neutral in the meter base.

These are the same guys who won't admit an inground concrete pool is an electrode, the biggest Ufer in the system. wink

The EGC and the bonding grid get bonded all over that system. (Pumps, lights, pool covers, heaters etc) and they are all at least 12ga wire. That is a lot of copper that electrons can flow through.

I went ahead and drive rods at the AC compressors and sat dishes, connected to the grounding system with 2ga (I had a bunch) I figure a big equipotential grid around my whole house should help with the surge protection. Then I stack layers of protectors on that.


Greg Fretwell
Joined: Apr 2002
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Here in NJ, one POCO does NOT allow the GEC to be terminated in the meter base, or pass thru the base. Another POCO allows termination at the neutral within the meter base. There are two other POCOs that I am not familiar with.

The towns I inspect in are all in the "No GEC in the meter base"; on occasion we see a EC from the southern part of the State, and we know where he's from by the GEC terminated in the meter base.


John
Joined: Jan 2005
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Cat Servant
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HotLine, you caught me in a major mis- speak. Probably best to bleep out my earlier comments about running the GEC in the meter base and explain what I was really thinking about before I had a senior moment.

My typical service change does not have separate base, disconnect, and overload components. All three are contained in the same “all in one” panel. In these panels you land the GEC to the ground bus. A factory installed bar bonds the neutral buss to the ground buss.

The “other” way — and here is where I got confused — is done where you have several services supplied by one service drop. Imagine an apartment building or RV park. Here there is a main disconnect before the meters. When all these services are in the same building, the GEC lands in the main disconnect. When the meters serve different structures there are additional ground rods at each structure, with those GEC’s landing on the ground buss.

When I have separate structures, I maintain separation of the neutrals from the grounds from individual disconnect at each meter. That’s the only place where the grounds and neutrals bond.

I apologize for my confused answer above.

Joined: Apr 2002
Posts: 7,381
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Reno,
I'm a guy with senior moments also, so no problem.

Here, 'all-in-ones' do not exist. Common for a SFD is riser to meter pan, to panel, or to a main disco IF the panel is not behind or directly in the basement. (Let's not go there with the "distance")

Multi-family use meter stacks. and over six they have a main disco.

Now, with the 2020 requirement of the 'emergency switch' on the exterior, there will be a 'main' after the meter.
With the current materials issues, that has been a problem. Our POCO has yet to approve a meter/main combo unit.

BTW, Thank you for generating a thread that generated some debate.

Last edited by HotLine1; 05/06/23 10:12 AM.

John
Joined: Jul 2004
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G
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The first place we saw meter/mains was in piling houses so they could have a disconnect at grade and it also made it easy to retrofit living space under the house in the flood zone after the CO. Ian has a lot of folks considering the wisdom of that decision after FEMA denied all claims for things below the permitted finished floor.
Meter mains are also the most common way to do a service upgrade. They typically leave the existing panel, rewired as a sub and then add new loads to another sub. I was just over at a neighbor's house looking over his plan to do an upgrade and define the scope of work he needs to contract. For him, it is actually fairly easy. His grounds and neutrals are already on separate buses in the main so he only has to lift the MBJ in the existing and pull in a new EGC. (back to back install) He may get away with only a few hours of billable time to swap out the existing meter can with an all in one. His plan is to add another 50a for the RV he is living in now because of the flood and for his new Tesla when he gets it. I am not willing to bet which will come first. The meter main he has picked out has a bunch of slots so he will have plenty of growing room. I imagine 320a is probably all FPL will give him but that should be plenty. I am curious if they even swap out the 2 ga aluminum drop. They are real bad about that. One of my other friends had to fight to get a heavier drop, They said they doubt he was ever even going to stress the drop he had.


Greg Fretwell
Joined: Jul 2002
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Greg,
Are the bits of rebar that form that system actually welded together with a stick welder along it's length or does it merely expect that the contact between the rods with tie wires "is enough" to carry fault currents after the concrete has been poured over it?

Joined: Jul 2004
Posts: 9,923
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G
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The concrete itself is the conductor. Rebar is lapped and ties for 48x the diameter to be considered "continuous" and it is felt that the physical contact and the concrete itself is enough to establish a ground reference for the grounding electrode system. Fault current itself is send back to the utility via the bonded neutral, not the GES. The GES is really only there to establish a ground reference and mitigate transients, not fault current.

Quote
250.4(A)(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that
are grounded shall be connected to earth in a manner that
will limit the voltage imposed by lightning, line surges, or
unintentional contact with higher-voltage lines and that will
stabilize the voltage to earth during normal operation.


Greg Fretwell
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