Fire Pump and Jockey Pump Circuit with Taps?

[Tainted]

An electrician has installed a new fire pump and jockey pump circuit and I am doing my part in due diligence to ensure it is properly installed. The fire pump and jockey pump are sharing the same service switch (see picture). The load side of the meter/disconnect switch combo has two lugs per phase which connect to the fire pump and jockey pump.

Jockey pump (1HP) is using 3#10 wires and fire pump (20HP) is using 3#2 wires (THWN-2 in rigid galvanized steel conduits). Both pumps are 208V 3-phase.

Jockey pump is fused at 15 amps and fire pump is fused at 350 amps. The service switch is fused at 400 amps.

Both fire pump and jockey pump is in the electrical service room so not concrete encasement or fire rating is needed.

I believe the fuses are the correct sizes however I am not too sure about the wire sizes. If the fire pump and jockey pump circuits are connected to the lugs at the load side of service switch, is that considered a tap and therefore should these conductors follow the tap rule? The length of these "taps" are 23 feet. See picture for full oneline diagram.
I think using 3#10 wires for the jockey pump is incorrect since it is a violation of the tap rules. This makes me question if tap rule applies for fire pump too.

 

[tom baker]

Normally there are no OCPDs ahead of the fire pump. Size wires like a motor load
Check for voltage drop limit is 3%

 

[Tainted]

Normally there are no OCPDs ahead of the fire pump. Size wires like a motor load
Check for voltage drop limit is 3%

Gonna try and see if it's been allowed in NYC to not have an OCPD device ahead of fire pump.

Should the jockey pump follow 430.28? Circuit between service switch and jockey pump disconnect switch is 23 feet. funny thing is there is no feeder before the lugs so...

 

[tom baker]

It’s much simpler to have. No ocpd for fire pump, I have never wired a jockey pump so don’t know if it can be wired direct
Also NFPA 20 goes hand in hand with Art 695. 20 has good info on entire system, not just electrical

 

[augie47]

I don't have my NFPA 20 handy but I believe you will find the jockey pump wouold have to compky wuiith 240.21 and in your case with 23', it does not,

 

[mayanees]

Normally there are no OCPDs ahead of the fire pump. Size wires like a motor load
Check for voltage drop limit is 3%

Tom,
A correction to the voltage drop for fire pumps is 15% for starting and 5% for running.
695.7 Voltage Drop.
(A) Starting.
The voltage at the fire pump controller line terminals shall not drop more than 15 percent below normal (controller-rated voltage) under motor starting conditions.
(B) Running.
The voltage at the load terminals of the fire pump controller shall not drop more than 5 percent below the voltage rating of the motor connected to those terminals when the motor is operating at 115 percent of the full-load current rating of the motor.

 

[Tainted]

I don't have my NFPA 20 handy but I believe you will find the jockey pump wouold have to compky wuiith 240.21 and in your case with 23', it does not,

Don’t you mean 430.28, not 240.21?

 

[JoeStillman]

Don’t you mean 430.28, not 240.21?

430.28 and 240.21(B)(2) are saying the same thing. The 25-foot tap rule requires the conductors to have at least 1/3 the ampacity of what they are tapping. The fuse for the jockey pump needs to be within 10 feet of the 400A switch, or else be fed with wire having an ampacity of 133A.

 

[Tainted]

430.28 and 240.21(B)(2) are saying the same thing. The 25-foot tap rule requires the conductors to have at least 1/3 the ampacity of what they are tapping. The fuse for the jockey pump needs to be within 10 feet of the 400A switch, or else be fed with wire having an ampacity of 133A.

240.21 tells you that it shouldn't be less than 1/3 of the overcurrent device, but 430.28 tells you it shouldn't be less than 1/3 of a feeder.

So do I follow both or just 1 of them?

 

[JoeStillman]

240.21 tells you that it shouldn't be less than 1/3 of the overcurrent device, but 430.28 tells you it shouldn't be less than 1/3 of a feeder.

So do I follow both or just 1 of them?

Your picture shows the tap at the OCPD.

 

[Tainted]

Your picture shows the tap at the OCPD.

Hmmm good point

 

[d0nut]

I could be wrong, but I always thought that 695.4(B)(1) would preclude an installation like what is shown in the sketch. Whenever I have designed a fire pump I have called for a service rated fire pump controller and just ran the service entrance conductors directly from the transformer to the controller with no intervening disconnecting means.

 

[gadfly56]

I could be wrong, but I always thought that 695.4(B)(1) would preclude an installation like what is shown in the sketch. Whenever I have designed a fire pump I have called for a service rated fire pump controller and just ran the service entrance conductors directly from the transformer to the controller with no intervening disconnecting means.

You can't have more than one disconnecting means between the service entrance and the fire pump controller. NEC 2017 695.4(B)(1). This does not appear to be one of the cases where exceptions apply under 695.3(C).

 

[Tainted]

You can't have more than one disconnecting means between the service entrance and the fire pump controller. NEC 2017 695.4(B)(1). This does not appear to be one of the cases where exceptions apply under 695.3(C).

So would the oneline diagram I drew not comply? by the way the fire pump controller has a disconnect handle. The way the electrician designed this is weird and in my opinion redundant

 

[tom baker]

So would the oneline diagram I drew not comply? by the way the fire pump controller has a disconnect handle. The way the electrician designed this is weird and in my opinion redundant

The fire pump controller protects against short circuits but not overloads

 

[Tainted]

The fire pump controller protects against short circuits but not overloads

Wouldn't the service switch fuse protect it against overloads since some fuses have the capability of protecting against short circuits and overloads?

 

[tom baker]

The fire pump is sacrificial in a fire it is intended to run to destruction. That’s why there are no overloads in the controller. It’s better and simpler to have no disconnects ahead of the fire pump controller.

 

[tom baker]

90.3 is the most important section in the NEC. please review it to see article 695 relationship to the rest of the NEC

 

[Tainted]

Your picture shows the tap at the OCPD.

to be fair, 240.21 is for feeder taps too... so which one does it really apply to? 240.21 or 430.28?

 

[Tainted]

This scenario is really really odd because 240.21 and 430.28 all are about feeder taps, but we are not tapping at any feeders. We are tapping lugs on the load side of a service fuse. So tap rule does this apply to?