GEC Question

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JOHNEO99

JOHNEO99

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Northern Illinois
Ok heres the scenario. I have a 600 amp 6 gang meter bank outside with each meter having its own disconnect/breaker. There will be six panels inside the building with main breakers instead of main lugs to different offices.

I know the GC, EG, and GEC should terminate at the same spot at the main disconnect.

How is the main disconnect determined in this situation? Is the main disconnect considered to be at the meter bank or inside at the panel main breaker.

I would like for the panels inside to be considered the main disconnects so i dont have to bring 6 GECs back to the meter bank. I would just run GEC from each respective to water supply/copper in each unit.
 
wbalsam1 said:
Look up "Service Point". Also your interior panels would be on the load side of your service disconnecting means. :smile:
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Yes I understand. I have run these six pipes in IMC from the meter bank to each panel and did not run the actual GEC with the two hots and nuetral. From each panel had a GEC from panel to water supply pipe(6). I guess this was acceptable because the pipe was the actual GEC from the meter bank to the units but the actual electrode would only be the rod outside and the conductor inside just a bond to water pipe system.

But the inspector wanted the MBJ at the panels which is confusing me I guess.

Im a little confused here but I guess I should run 1- 1/0 from 600amp meter bank to main water feed. Then 1-#4 for each respective panel (200amp) and have the MBJ at the meter bank. Then bond all the panels inside to water pipes and steel.
 
JOHNEO99 said:
Ok heres the scenario. I have a 600 amp 6 gang meter bank outside with each meter having its own disconnect/breaker. .
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(these are thefefore your service disconnects)
JOHNEO99 said:
There will be six panels inside the building with main breakers instead of main lugs to different offices.

I know the GC, EG, and GEC should terminate at the same spot at the main disconnect.

How is the main disconnect determined in this situation? Is the main disconnect considered to be at the meter bank or inside at the panel main breaker.

I would like for the panels inside to be considered the main disconnects so i dont have to bring 6 GECs back to the meter bank. I would just run GEC from each respective to water supply/copper in each unit.
Click to expand...
Your GEC will have to originate at your service equipment (outside) {250.64[d] in -08}.
If your water supply in each building is mechanically isolated from the other occupancies by use of non-metallic piping then you can BOND from each occupancy to it's own water line per 250.104{a)(2).
 
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JOHNEO99 said:
But the inspector wanted the MBJ at the panels which is confusing me I guess.

.
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He wants a bond jumper in each of your 6 inside panels ?
Bonding what ? neutral to can ?
I would think this is a violation of 250.24(A) (5)
 
Each service disconnect enclosure must have the bonding jumper. IMO based on the info we have the inspector is correct per 250.24(B)
 
JOHNEO99 said:
Ok heres the scenario. I have a 600 amp 6 gang meter bank outside with each meter having its own disconnect/breaker. it.
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Bob, would these outside disconnects not be service disconnects. JohnE stated the inspector "wanted a MBJ" at the panels. Would that be correct?
 
I am not sure of the lay out here, but if he has six service disconnects he must have 6 bonding jumpers located in the same enclosure as the service disconnects unless they are already in a common enclosure.
 
The description of a 600A 6 gang leads me to believe this meter pack is like most I see, the neutral is going to be common to all six disconnects requiring one MBJ in the meter pack if not and it is 6 separate services the situation really does not change. This is the service and the MBJ, GES via GEC(whatever is available) and any bonding to building steal or the main building metal water pipe system needs to take place here. Like it was mentioned before isolated metal water pipe systems could be bonded to that occupancies panel. The panels inside would be sub-panels and any neutral to ground connections would be incorrect. An EGC would be required to each sub-panel. You mentioned pipe or conduit this could be considered an EGC if it was a properly installed metallic raceway, if not you are stuck pulling that four wire.
 
augie47 said:
(these are thefefore your service disconnects)
Your GEC will have to originate at your service equipment (outside) {250.64[d] in -08}.
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I agree that the location of the service disconnecting means will be the disconnects located at the meter equipment outside. The panels inside are subpanels.


The GEC could possibly be a "common GEC" if there is one water service to the building, with GEC taps into each disconnect outside.

If each unit has it's own water supply, than the use of a common GEC would not be permitted.
 
For what it is worth, I agree that the service disconnecting means is at the meter positions, the next downstream panelboard is a not a service disconnecting means and the neutral is not to be bonded to ground there, and the GEC is to originate at the service disconnecting means in the meter center. Also, you do need a forth wire for the grounding conductor but that can be a metallic conduit or EMT. :smile:
 
Thanks for all the replies I really do appreciate the discussion. I def. have a better idea here and you all have helped very much.

I have one last question. Since the main service disco is outside Im pretty sure I can have main lug panels vs. main breaker panels since these unit panels are essentially sub-panels. This would save some dough. Am I correct?

I really dont do alot of big services but I believe main lug panels are fine according to all I have read.

Thx
 
Main lug panels should be okay per NEC if all panels are in the same building as the service. You might check local AHJ, job specs, engineers or owners for different requirements.
 
JOHNEO99 said:
Ok heres the scenario. I have a 600 amp 6 gang meter bank outside with each meter having its own disconnect/breaker. There will be six panels inside the building with main breakers instead of main lugs to different offices.

I know the GC, EG, and GEC should terminate at the same spot at the main disconnect.

How is the main disconnect determined in this situation? Is the main disconnect considered to be at the meter bank or inside at the panel main breaker.

I would like for the panels inside to be considered the main disconnects so i dont have to bring 6 GECs back to the meter bank. I would just run GEC from each respective to water supply/copper in each unit.
Click to expand...

This is the end of the service. You need the GEC here.
 
JOHNEO99 said:
I have one last question. Since the main service disco is outside Im pretty sure I can have main lug panels vs. main breaker panels since these unit panels are essentially sub-panels. This would save some dough. Am I correct?

I really dont do alot of big services but I believe main lug panels are fine according to all I have read.

Thx
Click to expand...


As long as the subpanels you are discussing have some type of OCPD as per 408.36, you are good.
 
JOHNEO99 said:
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I have one last question. Since the main service disco is outside Im pretty sure I can have main lug panels vs. main breaker panels since these unit panels are essentially sub-panels. This would save some dough. Am I correct? ...........Thx
Click to expand...

This is my opinion. Please wait for other opinions before accepting my "take" on this. Here it is:Once you have established your service point (at the metering location), the conductors that originate in the service equipment (metering location) and terminate in the individual units are considered "feeders". This is where 225.31 kicks in requiring a disconnecting means for those conductors serving the building. 225.32 describes the location and 225.36 requires that the disconnecting means be suitable for service equipment (even though these disconnects are not the actual service disconnecting means). Of course if the unit only needed six or fewer throws of the hand (225.33) to disconnect all circuits within it, then 225.34 would come into play.
 
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