Bonding Fire Sprinkler System

[cyado1607]

I have a question on bonding the fire sprinkler system. I know that you can bond to wherever it is accessible, However when you bond within the entry of the building or within 5' is this practice unsafe? When lightning hits and if it were to go to the bonding wire to the fire sprinkler could it potentially "blow out" or damage the riser? Now lets say it is bonded somewhere else, could it potentially damage the fire sprinkler heads themselves?
thanks

 

[electricalperson]

i dont think bonding the sprinkler pipe within 5 feet of entry to the building will create anymore danger than bonding it somewhere else. the pipe coming into the building is a large cast iron pipe thats located pretty deep underground. the pipe usually is bonded through building steel by all the beam clips anyway

 

[augie47]

many sprinkler systems use a type of coupling that will "isolate" sections of sprinkler piping, therfore, in using it a a ground electrode you would have to connect prior to these couplings.
If you were truly trying to bond the entire system you would need lots of jumper

 

[cyado1607]

i guess i am just trying to find out if there is any potential danger to firefighters going in with an energized fire sprinkler system

 

[JohnJ0906]

I usually see sprinkler systems supported from the building steel - with metal treaded rod and metal brackets. I think that would do a good job bonding the system.

 

[LarryFine]

I have a question on bonding the fire sprinkler system.

Check with the sprinkler people first. Here, I was told we cannot use the sprinkler piping for grounding on a recent job.

 

[eprice]

Check with the sprinkler people first. Here, I was told we cannot use the sprinkler piping for grounding on a recent job.

I'd like to have a code reference for what they told you. It seems to me that the sprinkler line into the building is a metal underground wter pipe described in 250.52(A)(1) and therefore required by the NEC to be used as a grounding electrode.

 

[mpd]

I may be wrong but I thought there was an NFPA sprinkler code that does not allow the sprinkler to be used as a grounding electrode, and I agree the sprinkler fittings isolate the sections of pipe

 

[LarryFine]

I'd like to have a code reference for what they told you.

From NFPA 13, 1999:

5-14.4.3.5: In no case shall the pipe be used for grounding of electrical systems.

The use of sprinkler or underground piping for electrical grounding increases the potential for stray currents and increased galvanic corrosion. In addition, the use of nonconductive joints may not provide the expected ground. Electric equipment should be grounded in accordance with NFPA 70; National Elecctrical Code.
(Automatic Sprinkler Systems Handbook)

By the way, the only electrodes in the entire building were two driven rods; the domestic water system was all-new plastic.