Multiple Fire pump- Electrical Load calculations

[monitaverma]

Hello,

Please see the attached SLD. We are upgrading the power for the entire campus. Each building on the campus has a 30 HP fire pump. FPB#2 is the board that will feed all the fire pumps.

The breaker size for each fire pump is based on the fire pump LRC, which is 240A.

My question: Since the fire pumps are being connected after the meter, should the service board be sized to include both the FPB load (720A) and the MSBH2 load (933A), for a total of 1,653A? In other words, does the MSBH2 board need to be rated for 2,000A? or are we ok with 1200Amps?

 

[Julius Right]

It seems to me the Main Switchboard [MSBH2] it is not the source but the “main consumers” 
The main switch has to be-at least- 2000 A rated.

 

[tjdilly]

There should not be a main switch ahead of the meter other than the MV switch on the primary of the transformer.

Chapter 6 Special Equipment: National Electrical Code, 2023 | UpCodes

UpCodes offers a consolidated resource of construction and building code grouped by jurisdiction

up.codes

You also should have a separate vertical section for the tap itself, or make sure you can fit both the tap and the meter in one section.

Fire Pump Circuit

I have attached a a one line sketch showing utility xfrm. feeding a MDP with full generator back up. It is my understanding I am allowed to feed a fire pump circuit as shown on the CB #1 from the MDP as shown. The only requirement is that this circuit breaker shall carry the the locked-rotor...

forums.mikeholt.com

Speculating here, but could you do multiple taps, one per pump, and get rid of FPB?

 

[Julius Right]

Thank you, tjdilly for your remarks. I am not a Fire Pump protection specialist, indeed, and Chapter 6 of NEC- Chapter 6 Special Equipment- mainly art. 695 Fire Pumps-is not my domain of activity.
So, if the supply source is a transformer and for supervised location only-see art. 450.3- you don't need a secondary protection. According to art.695 (B) Conductor Size. and 695.5 Transformers the two switches from my above sketch are not required-even not permitted.