Help with proper grounds on 4-gang meter pan

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jjhoward

jjhoward

Senior Member
Location
Northern NJ
Occupation
Owner TJ Electric
I have a 4-family apt. with 4 seperate meters.
1 water meter for the building.
4 breaker panels, one in each seperate basement.
The water meter is one of the basements.
What is the proper grounding for this install?
2 grnd rods at the breake panel in the basement with the water meter?
2 grnd rods at any one of the them.
2 at each (8 total??)
Thank you.
 
Re: Help with proper grounds on 4-gang meter pan

First, is the incoming water pipe metal or plastic? Can you verify that it's 10' or longer underground if indeed it's metal? If you can use the water pipe as a grounding electrode, you will have to supplement it with an additional rod. Now, everyone drives 2 supplemental rods because it's easier than attempting to prove that the first rod has 25 ohms or less impedance. Is that clear as mud? :)
 
Re: Help with proper grounds on 4-gang meter pan

I would install 2 rods at the meter pack location, and the cold water ground should be from 5' inside the structure, to the service disc
means. If it's a combo meter / disc setup one run will do. If it's 4 individual discos, I would run 4 individual grounds to the water line.
 
Re: Help with proper grounds on 4-gang meter pan

I actualy heard grounding the water system is bad. Is this true or not. I've had some inspectors tell me to take this off.
 
Re: Help with proper grounds on 4-gang meter pan

Hi Mnt,
Yes, 4 seperate basements.
Peter_d, water line is copper.
Megawatt, will probably install a meter pack with disconnects. With the disconnects at the meter pack, that can be my point for ground rods and attachment to the water line.
Can I run SEU to all breaker panels and bond the grounds of the breaker panels to the water line in the building? Or should I run SER from the meter pack w/disconnects?
 
Re: Help with proper grounds on 4-gang meter pan

With the disconnects at the meter pack, that can be my point for ground rods and attachment to the water line.
Click to expand...
If I'm understanding your setup correctly, yes, your grounding and bonding would be done at the first disconnecting means, in this case your meter pack.


Or should I run SER from the meter pack w/disconnects?
Click to expand...
Yes, you would need to now run SER cable to provide separate neutral and grounding conductors at the subpanels. All grounds and neutrals would be separate beyond the first disconnecting means. You could not accomplish this by running SEU cable.

[ October 04, 2005, 05:11 AM: Message edited by: infinity ]
 
Re: Help with proper grounds on 4-gang meter pan

I agree with Infinity (cool name by the way)

Your grounding and bonding must be done at the service disconnect which you will have four of at the meter pack. From that point keep the neutral isolated.

It does not sound like you have a choice about placing the service disconnects grouped outside.


I actualy heard grounding the water system is bad. Is this true or not. I've had some inspectors tell me to take this off.
Click to expand...
Forget about if it is good or bad :D
 
Re: Help with proper grounds on 4-gang meter pan

Thank you all for the input.
Absolutely clear when the disconnects are at the meter pack: 2 grnd rods and water line, SER to the breaker panels (now set up as sub panels).

What do I do if there are only meters with SEU run to the seperate breaker panels in the seperate basements?
 
Re: Help with proper grounds on 4-gang meter pan

What do I do if there are only meters with SEU run to the seperate breaker panels in the seperate basements?
Click to expand...
Assuming that you mean there will be no disconnects at the meters you would end up with a few violations. For one the service entrance conductors must terminate in a disconnect as soon as they enter the building, and secondly the disconnects would need to be grouped together, so running them into separate basements would not be permitted.


I'm sure that there are some other things that I've left out.


Trevor
 
Re: Help with proper grounds on 4-gang meter pan

Not sure if there is any violation with the proposed installation:
4 meters on the exterior of the house (in a quad meter pack.)
4 seperate SEU cables out the bottom of the meter housing run along the exterior of the building, each one of the 4 SEUs entering their respective basements right into a breaker panel. Each SEU run from the meter pan to their basement are different lengths.

The 4 apartments are all next to each other, in the same building seperated by interior walls. Seperate basements accessable only through the seperate apartments.

I don't know of requirment that there be a disconnect outside since the service conductors enter the building only at their breaker panels.

If this is installed in this manner, what to do about grounding? There is a single H2O meter, thus the water lines in all 4 apartments are common.
 
Re: Help with proper grounds on 4-gang meter pan

Originally posted by jjhoward:
I don't know of requirement that there be a disconnect outside since the service conductors enter the building only at their breaker panels.
Click to expand...
Your right the you can run the service conductors as far as you want on the outside of the building and there is no NEC requirement that the disconnects be outside.

However the disconnects have to be grouped in one location.

230.72 Grouping of Disconnects.
(A) General. The two to six disconnects as permitted in 230.71 shall be grouped. Each disconnect shall be marked to indicate the load served.
Click to expand...
I can't see it passing if the disconnect are spread out through the cellar.
 
Re: Help with proper grounds on 4-gang meter pan

iwire wrote:
I can't see it passing if the disconnect are spread out through the cellar.
Click to expand...
Wouldn't the exception to that happen if the four dwellings are seperated by firewalls?

jjhoward,

Are the seperator wall fire rated?

If so, I'd say you can have up to six disconnects inside each of the four units.
 
Re: Help with proper grounds on 4-gang meter pan

Originally posted by al hildenbrand:
Wouldn't the exception to that happen if the four dwellings are seperated by firewalls?
Click to expand...
What exception?

I can't think of one for his application.

Thats not to say I have not been confused before by the NEC in regards to the number of services and disconnects allowed.
:p
 
Re: Help with proper grounds on 4-gang meter pan

Well, quite simply, if the firewalls allow the local officials to deem the individual dwellings and separate buildings even though they have a common wall, then there could even be separate PoCo drops to each dwelling.
 
Re: Help with proper grounds on 4-gang meter pan

Al from my understanding 230 at that point they would have to have 4 services then then could have 6 disconects at each service. :confused:
 
Re: Help with proper grounds on 4-gang meter pan

Hence my question to JJHoward about the firewalls.
 
Re: Help with proper grounds on 4-gang meter pan

Originally posted by al hildenbrand:
Hence my question to JJHoward about the firewalls.
Click to expand...
He only has one service, six grouped disconnects per service. He would need the power company to bring in 3 more services.

For what its worth that is what I saw when I was in Pierre's area of NY.

A row of connected condos each one with it's own service drop from the POCO. Kind of ugly right on the front of the houses.
 
Re: Help with proper grounds on 4-gang meter pan

Originally posted by al hildenbrand:
Hence my question to JJHoward about the firewalls.
Click to expand...
Uh oh....I remember that debate quite clearly. :eek: However, since then I have learned that the firewalls may not be an issue at all in the case of condos. I was listening to one of those legal advice shows on talk radio, and learned that if you own a condo, you legally don't even own the sheetrock and 2x4s between the condos. Now, this was a local program and perhaps this is unique to my area, and I expect that different areas have different rules.
 
Re: Help with proper grounds on 4-gang meter pan

Hello All,
RE: firewalls in this building.
There is only 1 firewall seperating the middle of the building.
Thus there are two apts on each side of the firewall.
Sounds like the disconnects should be grouped per 230.72, thank you for the reference Iwire.

I can add that to my discussion with the owner when I give her the price for that meter pack w/disconnects :)
 
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