Our utility company will supply 5 service laterals to 5-100amp panels in a basement.Would I be required to have 5 ground rods with 5-#6 grounding electrode conductors from these panels? Also from the neutral bus in each panel, take grounding conductors to the metal water piping? Thanks Boomer
Apartment Building Grounding
- Thread starter boomer
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pierre
Senior Member
- Location
- Westchester County, New York
Re: Apartment Building Grounding
This is an interesting question in as far as having five service laterals to the same building for 100 amp services.
Each service is required when grounded to have a connection to the available grounding electrode(s).
Each service you connect to the cold water. You will be required to supplement the cold water with another electrode, which as you stated is a groundrod. The question is, are six different ground rods required? IMO one ground rod would suffice and an additional ground rod bonded to that one as per 250.56 if the 25 ohms to ground is not measured.
Pierre
After reading your post again and remembering how different other parts of the country perform the work, more details of how the building is supplied with the cold water, and how the building is divided into the five units is necessary to provide a more thorough answer.
[ January 03, 2004, 09:59 AM: Message edited by: pierre ]
This is an interesting question in as far as having five service laterals to the same building for 100 amp services.
Each service is required when grounded to have a connection to the available grounding electrode(s).
Each service you connect to the cold water. You will be required to supplement the cold water with another electrode, which as you stated is a groundrod. The question is, are six different ground rods required? IMO one ground rod would suffice and an additional ground rod bonded to that one as per 250.56 if the 25 ohms to ground is not measured.
Pierre
After reading your post again and remembering how different other parts of the country perform the work, more details of how the building is supplied with the cold water, and how the building is divided into the five units is necessary to provide a more thorough answer.
[ January 03, 2004, 09:59 AM: Message edited by: pierre ]
Re: Apartment Building Grounding
This is an older apartment building, the basement is a common area to all so the panels are down there.My question is do I need to run 5-#6 copper wires to the ground rods or can you tap these 5 wires to a larger wire and take it outside the building to the 2 ground rods.Also the water system is old and all metal with easy access. Do I need to go from the neutral bars in the panels with grounding conductors to the water pipes? Boomer
This is an older apartment building, the basement is a common area to all so the panels are down there.My question is do I need to run 5-#6 copper wires to the ground rods or can you tap these 5 wires to a larger wire and take it outside the building to the 2 ground rods.Also the water system is old and all metal with easy access. Do I need to go from the neutral bars in the panels with grounding conductors to the water pipes? Boomer
- Location
- Massachusetts
Re: Apartment Building Grounding
250.58 requires all services in a building to use the same grounding electrode.
Two or more grounding electrodes that are effectively bonded together shall be considered as a single grounding electrode system in this sense.
It seems to me that is you run all 5 GECs (sized by 250.66) to the water meter then from there you jump outside with 6 AWG to a ground rod(s) you are all set.
250.64(D) allows GEC taps to separate enclosures for one service, I do not believe you could do that for separate services.
If this building has only one water service your bonding will already be complete by virtue of the EGC connection.
Not forgetting to put bonding jumpers where needed.
If this building has 5 separate water services not electrically connected everything changes.
250.58 requires all services in a building to use the same grounding electrode.
Two or more grounding electrodes that are effectively bonded together shall be considered as a single grounding electrode system in this sense.
It seems to me that is you run all 5 GECs (sized by 250.66) to the water meter then from there you jump outside with 6 AWG to a ground rod(s) you are all set.
250.64(D) allows GEC taps to separate enclosures for one service, I do not believe you could do that for separate services.
If this building has only one water service your bonding will already be complete by virtue of the EGC connection.
Not forgetting to put bonding jumpers where needed.
If this building has 5 separate water services not electrically connected everything changes.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Apartment Building Grounding
Jack,
I had the same question earlier, as the POCO here would not permit 5 separate laterals feeding 5 services to the same building.
Pierre
Jack,
I had the same question earlier, as the POCO here would not permit 5 separate laterals feeding 5 services to the same building.
Pierre
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