Please help solve a difference of opinion between several inspectors and electricians. We have 10 condos served on each end with a 5 gang meter center. Each unit is supplied with its own copper water line in direct contact with the earth more than 10'. Should you run the grounding electrode conductor from each service to one water line sized on 250.66 and the total circular mil area of all of the feeder conductors (underground service utility supplies service lateral) and bond each water line in each units sub panel or run one grounding electrode conductor sized for each feeder to each water main in each unit back to the service and not bond in the sub panels. Thanks for any help
Multi family grounding electrode system
- Thread starter dansan
- Start date
- Status
brian john
Senior Member
- Location
- Leesburg, VA
Re: Multi family grounding electrode system
Is the water line copper unit to unit, (Will there be a copper metallic connection with this water line unit to unit.)
Is the water line copper unit to unit, (Will there be a copper metallic connection with this water line unit to unit.)
Re: Multi family grounding electrode system
The condos are each fed with individual copper water lines and run to the main at the street. They are not connected except at the city main. My opinion is that this is one service at each end of the building and the code requires you to use A metal underground water pipe as the grounding electrode for each service(250.52 A 1 ) and 250.104 A 2 allows you to bond the metal water piping in each unit at the sub panels but we have a disagreement.
The condos are each fed with individual copper water lines and run to the main at the street. They are not connected except at the city main. My opinion is that this is one service at each end of the building and the code requires you to use A metal underground water pipe as the grounding electrode for each service(250.52 A 1 ) and 250.104 A 2 allows you to bond the metal water piping in each unit at the sub panels but we have a disagreement.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Multi family grounding electrode system
Hello Dansan
What we need to know is:
1. Does the building you are discribing, have firewalls between each unit?
2. How do the 'conductors' run from the meters to the units?
3. Are the Main Disconnects at the meters (outside) or are they at each individual condo?
Pierre
Hello Dansan
What we need to know is:
1. Does the building you are discribing, have firewalls between each unit?
2. How do the 'conductors' run from the meters to the units?
3. Are the Main Disconnects at the meters (outside) or are they at each individual condo?
Pierre
brian john
Senior Member
- Location
- Leesburg, VA
Re: Multi family grounding electrode system
Dan:
Is there continuity between the copper water lines?
Dan:
Is there continuity between the copper water lines?
Re: Multi family grounding electrode system
The mains are outside at the meter center , There are fire walls between each unit with a common area in the attic and ser feeding each units subpanel ran through the common area and fire caulked around the cables the continuity between the units' water lines will be made at the city main at the street but each unit is fed with its' own water line. The individual owns from paint to paint in each unit but the homeowners association owns the attic area and outside areas.
The mains are outside at the meter center , There are fire walls between each unit with a common area in the attic and ser feeding each units subpanel ran through the common area and fire caulked around the cables the continuity between the units' water lines will be made at the city main at the street but each unit is fed with its' own water line. The individual owns from paint to paint in each unit but the homeowners association owns the attic area and outside areas.
Re: Multi family grounding electrode system
dansan,
Are you saying that the "fire walls" between the units stop at the ceiling and do not continue through the attic to the roof? Are these true fire walls or are they fire partitions separating units (in IBC terms). Is the IBC adopted in your area? If so do these walls conform to all of the requirements of Section 705 (2000 IBC reference)?
dansan,
Are you saying that the "fire walls" between the units stop at the ceiling and do not continue through the attic to the roof? Are these true fire walls or are they fire partitions separating units (in IBC terms). Is the IBC adopted in your area? If so do these walls conform to all of the requirements of Section 705 (2000 IBC reference)?
brian john
Senior Member
- Location
- Leesburg, VA
Re: Multi family grounding electrode system
Dan:
It is there continuity between the units from the water line to the water line. Can you take your meter, continuity tester, megger ect and read 0 (or close to zero ohms) does the continuity tester light up.
Dan:
It is there continuity between the units from the water line to the water line. Can you take your meter, continuity tester, megger ect and read 0 (or close to zero ohms) does the continuity tester light up.
Re: Multi family grounding electrode system
They are 2 hour fire walls they run all the way to the roof. I have not actually checked with a meter but I would say that there is not continuity between the units' water lines because they are each individually fed and the main at the street is PVC. The area in the attic is considered "common" area and we allow them to run the feeders through this area since it is not owned by the tenant and therefore does not violate 230.3.
They are 2 hour fire walls they run all the way to the roof. I have not actually checked with a meter but I would say that there is not continuity between the units' water lines because they are each individually fed and the main at the street is PVC. The area in the attic is considered "common" area and we allow them to run the feeders through this area since it is not owned by the tenant and therefore does not violate 230.3.
Re: Multi family grounding electrode system
The critical question is still the location of the service disconnecting means. Is there a master disconnect ahead of the meter gang? Is there a unit disconnect located at each meter? Is there a main breaker or breakers in each units lighting and appliance panel board?
--
Tom
The critical question is still the location of the service disconnecting means. Is there a master disconnect ahead of the meter gang? Is there a unit disconnect located at each meter? Is there a main breaker or breakers in each units lighting and appliance panel board?
--
Tom
- Location
- Illinois
- Occupation
- retired electrician
Re: Multi family grounding electrode system
In my opinion, you connect the grounding electrode connector to the water line closest to the service disconnects and in each unit you bond the interior water piping system per 250.104(A)(2).
Don
In my opinion, you connect the grounding electrode connector to the water line closest to the service disconnects and in each unit you bond the interior water piping system per 250.104(A)(2).
Don
pierre
Senior Member
- Location
- Westchester County, New York
Re: Multi family grounding electrode system
Don
If the panels, located in each unit, were the service disconnect, would you still have the same answer?
Pierre
Don
If the panels, located in each unit, were the service disconnect, would you still have the same answer?
Pierre
- Location
- Illinois
- Occupation
- retired electrician
Re: Multi family grounding electrode system
Pierre,
It would still be permitted to connect the GEC at the meter even where the service disconnects are in the individual units. The connection is permitted to be at any point on the line side of or within the service disconnect. If the disconnects are in the individual units, I believe that you could make the installation either way, a common GEC at the meters or individual GECs at each disconnect.
Don
Pierre,
It would still be permitted to connect the GEC at the meter even where the service disconnects are in the individual units. The connection is permitted to be at any point on the line side of or within the service disconnect. If the disconnects are in the individual units, I believe that you could make the installation either way, a common GEC at the meters or individual GECs at each disconnect.
Don
- Location
- Illinois
- Occupation
- retired electrician
Re: Multi family grounding electrode system
Don
That could be a problem if there are "true" firewalls between the units. If there are firewalls, then each unit is a seperate building and 225.31 at each building.
Don
Re: Multi family grounding electrode system
We talked to Michael Johnston of IAEI and on code making panel 5. His clarification is that all of the copper water lines in direct contact with the earth for 10' or more must be bonded together with a bonding jumper sized per 250.66 to form the grounding electrode system and then take the grounding electrode conductor back to the service equipment. There will be no need for bonding in this case. The only time 250.104 will come into play is if they are each fed with nonmetallic water piping and then copper lines isolated in each unit. Hope this helps somebody.
We talked to Michael Johnston of IAEI and on code making panel 5. His clarification is that all of the copper water lines in direct contact with the earth for 10' or more must be bonded together with a bonding jumper sized per 250.66 to form the grounding electrode system and then take the grounding electrode conductor back to the service equipment. There will be no need for bonding in this case. The only time 250.104 will come into play is if they are each fed with nonmetallic water piping and then copper lines isolated in each unit. Hope this helps somebody.
- Status