Metal Underground Water Pipe

[aehterbulb]

My question is can I ground to a concrete ductile iron fire water pipe? The code (250.52) does not say in can't be fire water line, it simply states an underground water pipe with is in direct contact of earth for 10' and electrically continuous. I know ductile iron can be considered electrically discontinous because of its joints - do I need the civil to specify certain fittings because of this?

 

[raider1]

Underground metal fire sprinkler piping can not be used as a grounding electrode. This does not come from the NEC but from NFPA 13.

NFPA 13 Standard for the Installation of Fire Sprinklers 2007 edition, section 10.6.8 is where you need to look for this.

Chris

 

[Inspectorcliff]

Underground metal fire sprinkler piping can not be used as a grounding electrode. This does not come from the NEC but from NFPA 13.

NFPA 13 Standard for the Installation of Fire Sprinklers 2007 edition, section 10.6.8 is where you need to look for this.

Chris

I agree with Raider 1's post, Not his choice of Teams. But, yes most Firemarshall's will point that out, NO GROUNDS tied to the ductile piping system. Its a poor conductor anyway's.

 

[raider1]

I agree with Raider 1's post, Not his choice of Teams.

LOL, lately it has been kind of tough to be a Raiders fan. (They did beat the Broncos at investco field though.)

Chris

 

[Dennis Alwon]

Underground metal fire sprinkler piping can not be used as a grounding electrode. This does not come from the NEC but from NFPA 13.

NFPA 13 Standard for the Installation of Fire Sprinklers 2007 edition, section 10.6.8 is where you need to look for this.

Chris

Does anyone know why it is forbidden to bond a fire system sprinkler?

 

[Dennis Alwon]

Does anyone know why it is forbidden to bond a fire system sprinkler?

Bump-- anyone know why....

 

[infinity]

Does anyone know why it is forbidden to bond a fire system sprinkler?

I don't, and I think that somewhere there will a connection to the electrical system in a building that has a sprinkler system.

 

[augie47]

woops! I always thought it was a great idea. The big iron pipe in the ground vs. that 10 ft of 3/4 copper.....

 

[iwire]

If it is a new building he should be using a concrete encased electrode.

 

[nakulak]

They (cmp) should really address this. every jurisdiction where I work the code is different, some inspectors want the fire service grounded. I always ask cause otherwise I never get it right.

 

[raider1]

I don't know the reason why the fire code prohibits using the underground fire sprinkler pipe as a GE.

That being said, if you just use the NEC it requires the use of the underground fire sprinkler pipe as a grounding electrode. The fire sprinkler pipe is a "metal underground water pipe".

The thing I find interesting is that the pipe usually is bond either directly or indirectly via the building steel, so unless there is a dielectric fitting the underground portion of the sprinkler pipe will funtion as a grounding electrode.

Chris

 

[Dennis Alwon]

The reason I brought this up was because I know a fellow EC in our area that wants to use the sprinkler pipe as a gec to avoid going 200 feet to the water pipe on the other side of the building. I told him I didn't think he could do that. I also thought that if the water pipe from the sprinkler were allowed to be used then it would also have to be bonded back to the service anyway.

I find it very interesting that no one seems to know why we are not allowed to use it as a GE esp. since, as Chris stated, the NEC says we must use it.

 

[raider1]

The reason I brought this up was because I know a fellow EC in our area that wants to use the sprinkler pipe as a gec to avoid going 200 feet to the water pipe on the other side of the building.

Tell the fellow EC that ALL grounding electrodes that are present must be used. So if I have 10 underground metal water pipes then I must connect to all of them.

The 2008 NEC has made a clarification that where multiple CEE exist you only need to connect to one. But there is no such exception for multiple underground metal water pipes.

Chris

 

[augie47]

The thing I find interesting is that the pipe usually is bond either directly or indirectly via the building steel, so unless there is a dielectric fitting the underground portion of the sprinkler pipe will funtion as a grounding electrode.

Chris

A lot of the modern sprinkler systems use a type coupling that would act as a dielectric fitting. The supply pipe and the 1st few fittings are normally isolated from the remainer of the system by use of these couplings (in this area these type couplings are usually orange and bolt together) If you do wish to use the sprinkler as an electrode, the connection needs to be made prior to these couplings.
It would be interesting to see why the sprinkler code would not want the underground pipe to be used as the electrode it is.

 

[M. D.]

Does anyone know why it is forbidden to bond a fire system sprinkler?

I found this article ,..

http://findarticles.com/p/articles/mi_qa3737/is_/ai_n8765262

Q. Chapter 8 of NFPA 24 prohibits the use of steel pipe for grounding of electrical services, yet the electrical contractor on a recent project insisted on making the water supply pipe part of the building ground system. Is this correct?

A. Yes. Section 8-3.5 prohibits using the sprinkler water supply pipe as "the mechanism for grounding a building's electrical system. There are basically three reasons for this. Pipe connection methods-that is, threaded, grooved, and flanged fittings-don't provide assurance of electrical continuity; pipe materials may be nonconductors, such as polyvinyl chloride (PVC); and coating and wrapping underground systems might insulate the pipe from the earth surrounding it. Bonding the system pipe as a subcomponent of a building electrical grounding system is a requirement of NFPA 70, National Electrical Code. This minimizes a potential shock hazard to personnel and voltage differentials between the underground and aboveground piping systems.

 

[Dennis Alwon]

I found this article ,..

http://findarticles.com/p/articles/mi_qa3737/is_/ai_n8765262

So this appears to state that we cannot use the fire sprinkler pipe as an electrode but it must be bonded per the NEC. Yes?

It is interesting that one of the reasons for not allowing it as an electrode is the threads on the pipe. :-? We depend on threads all the time so why would the threads on the water pipe not be a good connection? :-?

I can understand if the pipe is insulated from the earth then it would make no sense to use it as an electrode just as we would not use plastic water lines as an electrode.

 

[M. D.]

It is interesting that one of the reasons for not allowing it as an electrode is the threads on the pipe. :-? We depend on threads all the time so why would the threads on the water pipe not be a good connection? :-?

My guess is that they use some sort of goop ,..like pipe dope ,..on the threads.

 

[tom baker]

Ductile Iron Pipe is not electrically conductive at the joints, there is a rubber gasket in the spigot and the male end is pushed in. There are bonding wedges that are used for electrical conductivity.

 

[tonyou812]

maybe its not a good conductor cause of the tape or paste they use on the pipe