On a multi family (apartment) project, there is about 3' of copper pipe in the sprinkler closet on the opposite side of the building (about 200') from the service). The plumbing inspector made the plumbers extend it -- the copper water pipe -- to 10' out from the building. Then, he, in conjunction with the electrical inspector, wants us to run 3/0 from the cold water to the service, again, about 200' on the other side of the building with MANY TURNS. We have a ufer ground at the service. Everything I've read says that you want your grounds to be SHORT and STRAIGHT. I asked if we could bust the slab at the sprinkler closet and ground the cold water to the slab (rebar). Then, we'd be tied in effectively. They looked at me like I was in fact the dumbest person they'd ever met and said that was NOT an effective ground. What am I missing here?
grounding cold water
- Thread starter LaCanaria
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charlie
Senior Member
- Location
- Indianapolis
Sorry, since they installed it, you have to comply. :smile:
250.52(A)(1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system.
250.52(A)(1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10 ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 ft) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system.
Cavie
Senior Member
- Location
- SW Florida
Your not the dumbset person they ever met, just a missinformed one. Don't feel bad. Many electricians miss this. They see $$$$$ in the ground with that 3/0. Metal fire stand pipe on one side. Service on the other side 200' away. When they fiind this out on the final it really pisses they off.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I would be interested as to why the plumbing inspector made the plumber run 10 feet of copper outside the building. There must be a local ordinance or the guys a jerk. 
charlie
Senior Member
- Location
- Indianapolis
I am betting on the latter.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I am betting on the latter.
I was trying to give the dude the benefit of the doubt but I do agree with you. :smile:
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Nope look at 250.66-- the pipe in 250.66(A) is not a water pipe
Yes, I saw that and retracted my post. I was thinking water pipe = pipe electrode. But you were too fast:smile:
If the building happened to have a steel framework, would it not be acceptable to bond the water pipe to the steel, and bond the steel to the service?
Steve
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I believe that is okay to do
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
This may help
Cavie
Senior Member
- Location
- SW Florida
See 250.104 A 1 and 2
- Location
- Illinois
- Occupation
- retired electrician
While there is no question that you have to use the metal underground water pipe as an electrode, there is no code reason why it can't be connected to the rebar near the water pipe and the rebar connected to the service panel. The NEC does not require that you run an individual GEC to the water pipe.
Is this an Underground sprinkler system supply ??
Is this an Underground sprinkler system supply ??
As I understand this?
This kind of brings about an interesting fact between NFPA documents (which was just discussed in another thread not long ago...).
If the OP is in fact referring to a copper fire protection underground supply line, this underground line is NOT permitted to be part of the grounding electrode system. This information is not in the NEC, but it is revealed in:
NFPA 24-2007 Standard for the Installation of Private Fire Service Mains and Their Appurtenances Underground piping:
Section 10.6.8 : In no case shall the underground piping be used as a grounding electrode for electrical systems. This does not preclude the bonding of the underground piping system to the lightning protection system as required by NFPA 780 in those cases where lightning protection is provided for the structure.
-and-
NFPA 13-2007: Standard for the Installation of Sprinkler Systems:
Underground piping: Section 10
10.6.8 In no case shall the underground piping be used as a grounding electrode for electrical systems. This does not preclude the bonding of the underground piping system to the lightning protection system as required by NFPA 780 in those cases where lightning protection is provided for the structure.
It seems to me:
While the underground metallic piping for a fire protection system cannot be used as a grounding electrode from Section 250.50, the interior and exterior metal water piping systems of the building do appear to require bonding under Section 250.104(A).
Section 250.104(A) does not designate where said bonding connection to this interior metal water piping system shall be made?
If the underground piping in the OP?s sprinkler closet is an underground supply line for the fire protection system, it does not appear to be necessary to bond the interior metal piping of this system at its origin ?
Am I understanding this correctly ??
mweaver
Is this an Underground sprinkler system supply ??
As I understand this?
This kind of brings about an interesting fact between NFPA documents (which was just discussed in another thread not long ago...).
If the OP is in fact referring to a copper fire protection underground supply line, this underground line is NOT permitted to be part of the grounding electrode system. This information is not in the NEC, but it is revealed in:
NFPA 24-2007 Standard for the Installation of Private Fire Service Mains and Their Appurtenances Underground piping:
Section 10.6.8 : In no case shall the underground piping be used as a grounding electrode for electrical systems. This does not preclude the bonding of the underground piping system to the lightning protection system as required by NFPA 780 in those cases where lightning protection is provided for the structure.
-and-
NFPA 13-2007: Standard for the Installation of Sprinkler Systems:
Underground piping: Section 10
10.6.8 In no case shall the underground piping be used as a grounding electrode for electrical systems. This does not preclude the bonding of the underground piping system to the lightning protection system as required by NFPA 780 in those cases where lightning protection is provided for the structure.
It seems to me:
While the underground metallic piping for a fire protection system cannot be used as a grounding electrode from Section 250.50, the interior and exterior metal water piping systems of the building do appear to require bonding under Section 250.104(A).
Section 250.104(A) does not designate where said bonding connection to this interior metal water piping system shall be made?
If the underground piping in the OP?s sprinkler closet is an underground supply line for the fire protection system, it does not appear to be necessary to bond the interior metal piping of this system at its origin ?
Am I understanding this correctly ??
mweaver
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I believe you must bonding the sprinkler pipe inside the building unless a fire code prohibits it. The underground sprinkler pipe is often separated with a dielectric fitting-- I am told -- so you would not be using it as an electrode. Remember the sprinkler pump would be grounding the pipe anyway.
Dennis,
I wasn’t sure if you were directing your post at mine above or not… (…If your were… Sorry I can be really slow, sometimes)
My research into the two above noted NFPA documents did not reveal any language which prohibited the bonding of these interior metal water piping systems (as required in the NEC Section 250.104).
I understand, as you do, that many times a dielectric fitting is installed which isolates the interior piping from the exterior piping. I only found this addressed here:
NFPA 13-2007: Standard for the Installation of Sprinkler Systems
Underground piping: Section 10
10.6.7 When it is necessary to join metal pipe with pipe of dissimilar metal, the joint shall be insulated against the passage of an electric current using an approved method.
(...I certainly could have missed something, I am not as familiar with these documents...)
With or without the dielectric fitting, the underground fire protection piping is still not permitted to be utilized as part of the grounding electrode system.
And Yes, I would agree, if an electric fire pump is present, the EGC on the pump will provide bonding for the metallic piping system (Note: a remote pump building may incorporate dielectric fittings separating this pump building’s metal piping from the occupancy building’s metal sprinkler piping system) ...I have seen some fire protection systems which had no pump...
In either case of dielectric ftg. incorporated or no dielectric ftg., if this is actually sprinkler piping in question, this is a bonding issue and not a grounding electrode issue, and for bonding; where that bonding connection is made to the interior piping system is not designated… (...not required at point of origin...)
Am I understanding this correctly ??
mweaver
I wasn’t sure if you were directing your post at mine above or not… (…If your were… Sorry I can be really slow, sometimes)
My research into the two above noted NFPA documents did not reveal any language which prohibited the bonding of these interior metal water piping systems (as required in the NEC Section 250.104).
I understand, as you do, that many times a dielectric fitting is installed which isolates the interior piping from the exterior piping. I only found this addressed here:
NFPA 13-2007: Standard for the Installation of Sprinkler Systems
Underground piping: Section 10
10.6.7 When it is necessary to join metal pipe with pipe of dissimilar metal, the joint shall be insulated against the passage of an electric current using an approved method.
(...I certainly could have missed something, I am not as familiar with these documents...)
With or without the dielectric fitting, the underground fire protection piping is still not permitted to be utilized as part of the grounding electrode system.
And Yes, I would agree, if an electric fire pump is present, the EGC on the pump will provide bonding for the metallic piping system (Note: a remote pump building may incorporate dielectric fittings separating this pump building’s metal piping from the occupancy building’s metal sprinkler piping system) ...I have seen some fire protection systems which had no pump...
In either case of dielectric ftg. incorporated or no dielectric ftg., if this is actually sprinkler piping in question, this is a bonding issue and not a grounding electrode issue, and for bonding; where that bonding connection is made to the interior piping system is not designated… (...not required at point of origin...)
Am I understanding this correctly ??
mweaver
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- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Correct but with a dielectric fitting I believe the piping would require bonding-- this would not be an electrode but bonding the piping system.
cadpoint
Senior Member
- Location
- Durham, NC
- Occupation
- Electrician - but not by NC Law.
I would be interested as to why the plumbing inspector made the plumber run 10 feet of copper outside the building. There must be a local ordinance or the guys a jerk.
City of Durham, makes old buildings install a water line backflow on the old line.
Don't have a point of reference, but its now there.
the install is after the main valve...
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Cavie
Senior Member
- Location
- SW Florida
Give that man a ceeegar
Sprinkler systems often contain numerous couplings (and elbows, tees etc) that by the way they are manufactured & installed are actually dielectric, so if you were to try and bond every section of metallic sprinkler piping it would take numeous jumpers. Since the sprinkler Code prohibits using the supply as a grounding electrode, I think you have a feasible argument not to install the GEC.
Probanky won't fly, but I'd fight for it.
Probanky won't fly, but I'd fight for it.
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