Meter Socket Grounding

mobo

Member
Location
MO USA
If you have a 240/120V, single-phase meter loop attached to a pole where it's overhead to overhead, with only the two phase wires (not the grounded conductor) coming down through the loop to the meter socket, then back up the loop from the meter socket, should, and how should, it be grounded?
 

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
I'm assuming that the service disconnect is somewhere further down stream? The meter socket and the riser conduits must be bonded to the neutral conductor. I would use an appropriately sized bonding jumper at the weather head from the neutral to a ground clamp on the riser conduit.
This sounds like a coop deal. Are they OK with this?
 
You can't? Usually if the neutral is present it needs to follow the phase leads as far as the service disconnect; off-hand I can't think of a relevant exception.

I do recall years back someone telling me this was common practice on farms.
 

ptonsparky

Senior Member
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
Electrical Contractor
If you have a 240/120V, single-phase meter loop attached to a pole where it's overhead to overhead, with only the two phase wires (not the grounded conductor) coming down through the loop to the meter socket, then back up the loop from the meter socket, should, and how should, it be grounded?
Do you own the meter loop or the POCO?

If you own it, do it over and bring the grounded conductor down in the meter loop. It does not need to go back up.

We can not have the line and load of that meter socket in the same raceway in this area. . The POCO does not supply up/down loops anymore. Only down, so a separate conduit back up for the load.
 

tom baker

First Chief Moderator
Staff member
By grounded you mean connection to a grounding electrode system? NEC does not require, POCO may require. In Wasington we can connect a GEC into the meter socket as its not accessible, however its allowed if the POCO requires.
 

mobo

Member
Location
MO USA
I'm assuming that the service disconnect is somewhere further down stream? The meter socket and the riser conduits must be bonded to the neutral conductor. I would use an appropriately sized bonding jumper at the weather head from the neutral to a ground clamp on the riser conduit.
This sounds like a coop deal. Are they OK with this?
Yes, the service disconnect is farther downstream.
 

mobo

Member
Location
MO USA
You can't? Usually if the neutral is present it needs to follow the phase leads as far as the service disconnect; off-hand I can't think of a relevant exception.

I do recall years back someone telling me this was common practice on farms.
The loop has a #6 bare wire coming out of the meter socket and it is bonded to the pole ground. So wondering if this would be considered kosher as far as grounding?
 

mobo

Member
Location
MO USA
Do you own the meter loop or the POCO?

If you own it, do it over and bring the grounded conductor down in the meter loop. It does not need to go back up.

We can not have the line and load of that meter socket in the same raceway in this area. . The POCO does not supply up/down loops anymore. Only down, so a separate conduit back up for the load.
POCO owns the loop.

What is the reason for not wanting the line and load in the same conduit?
 

mobo

Member
Location
MO USA
By grounded you mean connection to a grounding electrode system? NEC does not require, POCO may require. In Wasington we can connect a GEC into the meter socket as its not accessible, however its allowed if the POCO requires.
Yes, I meant grounding electrode system.
 

mobo

Member
Location
MO USA
This also got me thinking.....my brother has a service to an irrigation pump and it's a straight 3-wire, 3-phase service. No grounded conductor. I haven't looked at it yet, but how should that loop be grounded? It's about a 16 ft. loop with the meter socket on it.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
The loop has a #6 bare wire coming out of the meter socket and it is bonded to the pole ground. So wondering if this would be considered kosher as far as grounding?
If the pole ground is tied to the neutral, this conductor would functionally tie the meter base to the neutral. Is the #6 large enough for the service size?
 

tom baker

First Chief Moderator
Staff member
What's the reason/logic for not allowing loops?
Same reason meters are sealed. To prevent theft of power or in this case, a short between line and load. Keep in mind the POCO have a hundred years or more of providing power and have seen it all. The need to protect the cash register is paramount, so they write the rules. And the NEC does not require a meter.
 

tom baker

First Chief Moderator
Staff member
This also got me thinking.....my brother has a service to an irrigation pump and it's a straight 3-wire, 3-phase service. No grounded conductor. I haven't looked at it yet, but how should that loop be grounded? It's about a 16 ft. loop with the meter socket on it.
What type of three wire? 480 corner grounded?
 

mobo

Member
Location
MO USA
Same reason meters are sealed. To prevent theft of power or in this case, a short between line and load. Keep in mind the POCO have a hundred years or more of providing power and have seen it all. The need to protect the cash register is paramount, so they write the rules. And the NEC does not require a meter.
So more for preventing a short between line/load then, right? Because I can't see how not allowing meter loops prevents theft of power compared to a meter socket on a house. Unless I'm misunderstanding something.
 

tom baker

First Chief Moderator
Staff member
My experience with 3 phase 480 delta is limited. I had one that was corner grounded, the fused disconnect had a bus bar in the b phase, with a jumper to ground.
do all the voltages read 480 to ground?
 

mobo

Member
Location
MO USA
My experience with 3 phase 480 delta is limited. I had one that was corner grounded, the fused disconnect had a bus bar in the b phase, with a jumper to ground.
do all the voltages read 480 to ground?
No, all the voltages are different. And thanks for your replies.
 

mobo

Member
Location
MO USA
And if someone could educate me...lol....I assume the reason the meter loop would need bonded to the grounded conductor (neutral) is in case of a short which could result in a shock hazard?
 
Top