Fire Pump Controller Interlock

[kody916]

Greetings Everyone.

Need help with some queries that i have.

I have a situation where i am adding a new Fire Water Transfer Pump to an existing MCC. The same MCC also feeds an existing Fire Water Pump. Inorder to avoid overloading of MCC, only one pump needs to run at the same time i.e an interlock between existing Fire Water Pump and new Fire Water Transfer Pump.

1. Does NEC mention anywhere about interlock for fire pump?

Fire Pump is very critical and needs to be running all the time. Does it make sense to have an interlock between the two Pumps? My client is very adamant about adding the interlock even though i told him that fire pump needs to be running constantly.

The existing Fire Pump has an ECS Fire Pump Controller (website name is mastercontrols.com). I spoke to one of their engineers and he told me the wiring for the fire pump controller cannot be tampered with or changed because its factory wired. He did give me an option of adding a slave relay to the customer terminals on the existing fire pump controller......Has anyone dealt with this kind of situation?
Any advise or suggestions would be highly appreciated.

Thank You

 

[ActionDave]

You can't have a NEC compliant fire pump and jockey pump system that needs an interlock to stay alive when the time comes for the whole thing to go into action.
Get your code book out and turn to Art. 695

Overcurrent Device Selection.
Overcurrent protective device(s) shall be rated to carry
indefinitely the sum of the locked-rotor current of the
largest fire pump motor and the pressure maintenance
pump motor(s) and the full-load current of all of the
other pump motors and associated fire pump accessory
equipment when connected to this power supply.

Conductor Size.
(1) Fire Pump Motors and Other Equipment. Conductors
supplying a fire pump motor(s), pressure maintenance
pumps, and associated fire pump accessory equipment shall
have a rating not less than 125 percent of the sum of the fire
pump motor(s) and pressure maintenance motor(s) full-load
current(s), and 100 percent of the associated fire pump accessory
equipment.

 

[Jraef]

Greetings Everyone.

Need help with some queries that i have.

I have a situation where i am adding a new Fire Water Transfer Pump to an existing MCC. The same MCC also feeds an existing Fire Water Pump. Inorder to avoid overloading of MCC, only one pump needs to run at the same time i.e an interlock between existing Fire Water Pump and new Fire Water Transfer Pump.

1. Does NEC mention anywhere about interlock for fire pump?

Fire Pump is very critical and needs to be running all the time. Does it make sense to have an interlock between the two Pumps? My client is very adamant about adding the interlock even though i told him that fire pump needs to be running constantly.

The existing Fire Pump has an ECS Fire Pump Controller (website name is mastercontrols.com). I spoke to one of their engineers and he told me the wiring for the fire pump controller cannot be tampered with or changed because its factory wired. He did give me an option of adding a slave relay to the customer terminals on the existing fire pump controller......Has anyone dealt with this kind of situation?
Any advise or suggestions would be highly appreciated.

Thank You

I question the entire concept of having a Fire Pump Controller in or fed from an MCC at all. In most jurisdictions I've known of, Fire Pumps must use an NFPA 20 approved Fire Pump Controller and I know of no MCC mfr that offers this. The UL requirements for MCCs would preclude some of the NFPA 20 requirements for Fire Pump Controllers. Even if you meant you have a feeder breaker in that MCC feeding a separate FPC, that breaker must be capable of continuous locked rotor current of that motor, typically 600% of the FLA which means, as ActionDave said, grossly over sizing the MCCs capacity, unless perhaps you have a very small Fire Pump.