Electric Fire pump madness

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Sparky2791

Sparky2791

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Northeast, PA
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Electrical Design
I have read article 695 and NFPA 20 (several times)

Still confused on a few things.
Fire pump Service
695.3 A (3) Dedicated feeder. Can someone give me an example of what is meant by this section since this is one of the acceptable methods of providing power?

If I use 695.3 (1) (Tap section on switchboard ahead of the main) the fire pump feed is a service and will need a disconnect with overcurrent protection per 230.70 & 230.90. After I tap the service in the separate section and come out of the tap overhead I need to have a service disconnect located at the tap, no?

In what type of scenario of a service to a fire pump can you use 695.4 (A) Direct Connection? If it is a service it needs a service disconnect and OCP again to comply with 230.70 and 230.90. So not a direct connection. I realize 695.4 (B) allows this but why have (A) at all?

Thanks for any replies.
 
Most of the one I see have a direct connection to the service supply (POCO_)and the disconenct in the fire pump controller is the service disconnect so in compliance with 695.4(A).
 
augie47 said:
Most of the one I see have a direct connection to the service supply (POCO_)and the disconenct in the fire pump controller is the service disconnect so in compliance with 695.4(A).
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^^^^What augie47 said.
 
I've never seen the direct connection method. We also use a "tap" after the metering CT's to a disconnect.
 
If you tap the service before the main disconnect, it would still be considered service conductors and not be required to follow the tap rules. I have designed many services where the fire pump is tapped directly to the service conductors and routed straight into the building and into the fire pump controller without a contractor-provided disconnect. The fire pump controller or ATS usually is provided with a disconnect.
 
I have had a jurisdiction ask that we provide a disconnect on the outside of the building for every service. In this case I used a non-fused disconnect for the fire pump service, which I did not have to rate for the locked rotor amps because there was no overcurrent protection. This satisfied their disconnect requirement.
 
Johnhall30 said:
I have designed many services where the fire pump is tapped directly to the service conductors and routed straight into the building and into the fire pump controller without a contractor-provided disconnect. The fire pump controller or ATS usually is provided with a disconnect.
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How is that metered? Does the POCO give free electrons to the fire pump? :)
 
Johnhall30 said:
I have had a jurisdiction ask that we provide a disconnect on the outside of the building for every service. In this case I used a non-fused disconnect for the fire pump service, which I did not have to rate for the locked rotor amps because there was no overcurrent protection. This satisfied their disconnect requirement.
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Actually, the enclosure has to be rated for the locked rotor amps even if there are no OCPD's provided.
 
jim dungar said:
Wouldn't a non-load break device have to be rated to carry the same current as the conductors?
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Hmmm, I went back into 695 and part 9.2.3 in NFPA 20, I can't find anything there to support my claim. Unless someone else has other data, I'll withdraw my claim.
 
gadfly56 said:
Actually, the enclosure has to be rated for the locked rotor amps even if there are no OCPD's provided.
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I have asked that exact same question on this forum and never received an answer because I had the same thought. No OCPD why rate for LRC? What is the dictating part of the code that does not allow this?
 
Johnhall30 said:
I have had a jurisdiction ask that we provide a disconnect on the outside of the building for every service. In this case I used a non-fused disconnect for the fire pump service, which I did not have to rate for the locked rotor amps because there was no overcurrent protection. This satisfied their disconnect requirement.
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This is now part of the 2020 code for residential services, disconnect on the outside of the home. But nothing as far as commercial services.
 
LibertyEngineering said:
I have asked that exact same question on this forum and never received an answer because I had the same thought. No OCPD why rate for LRC? What is the dictating part of the code that does not allow this?
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Actually it is quite clear.
The last sentence of NEC 2014 Article 695.4(B)(2)(a)(1) says:
" The requirement to carry locked-rotor currents indefinitely shall not apply to conductors or devices other than overcurrent devices in the fire pump motor circuit(s)."
 
LibertyEngineering said:
I have asked that exact same question on this forum and never received an answer because I had the same thought. No OCPD why rate for LRC? What is the dictating part of the code that does not allow this?
Click to expand...
Rules in 695 modify the rules in chapter 1-4
See the most important rule in the NEC, 90.3
 
jim dungar said:
Wouldn't a non-load break device have to be rated to carry the same current as the conductors?
Click to expand...
It is an unlikely occurrence, given that the enclosure and disconnect have to be able to withstand short circuit current too, but the disconnect would have to be built to mechanically and thermally withstand the effects of the locked rotor current even when there is no OCPD.
A moot point given 695.4(B)(2)(a)(1).
 
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