Fire Pump Grounding

[jerryb]

Our office needing to design a fire pump installation for an existing building. The fire pump & its jockey pump will be feed in accordance with 695.3(A)(1) as a seperate electric utility service. The feeder will be run from the utility transformer, underground exterior to the building, stubbed into the pump room and connected to the pump controllers. The conductors are sized based on 430.6(A)(1) and Table 430.150. Voltage drop has been verfied as to be less than 15% as called for in 695.7.

My question is regarding the grounding of the new service. Article 695 makes no mention of grounding therefore am I to treat this as a seperate service and size the ground according to Table 250.66 and run that to the water pipe and a supplemental ground such as a ground rod? Which table would be used for the ground wire from the controller to the pump?

I find it very odd that the issue of Grounding is not at least mentioned and some direction is given back to Article 250.

Thanks for your help.

 

[jhines]

Re: Fire Pump Grounding

Article 250 does not exclude fire pump services (250-20). Suggest you treat them as any other service and follow article 250 requirements. If you check with the manufacturer of the controller, you should find it listed as service entrance equipment, but will probably find only one connection for the neutral/ground. Remember to take the neutral as it is the service return path for fault current.

 

[charlie]

Re: Fire Pump Grounding

90.3 states "Chapters 5, 6, and 7 apply to special occupancies, special equipment, or other special conditions. These latter chapters supplement or modify the general rules."

In other words, follow all the rules in chapters 1, 2, 3, and 4 unless they are supplemented or modified by Article 695.

 

[tom baker]

Re: Fire Pump Grounding

if its a new building use the reinforcing steel in the footing for your grounding electrodem, per 250.52 (A)(3), and of course bond any metal water pipes. Ground rods will not be needed with a 250.52(A)(3) electrode. this will give you a very good "ground" at essentially no cost.

 

[xoxota]

Re: Fire Pump Grounding

Refer to 230.95, exception #2.
xoxota

 

[websparky]

Re: Fire Pump Grounding

Most fire pumps rated 100 hp and over would require a disconnecting means rated at 1000 amperes or more. However, due to the emergency nature of their use, fire pumps are exempt from the provisions of 230.95.