Fire Pump Feeder Breaker

[faresos]

I have situation where we have the utility MV gear located outside the building and it distribute power to two MV switchgears inside the building. Each MV switchgear feed multiple 4000A, 480V substations (via transformer). Each substation are getting power from the MV gear feeder and a dedicated generator. We are planning on feeding the fire pump from two feeders from two different substation. The substation low voltage side is a switchgear construction. My question is, does the feeder breaker for the fire pump needs to be in a dedicated vertical section? I thought the vertical section is only required if we tap a head of the disconnecting means.

Thanks,

 

[augie47]

{bump}
I bumped this back to promote more input. I have an opinion, but I would rather you hear from someone with more Art 695 experience.

 

[gadfly56]

Generally you wouldn't put a breaker on the feeder, since it's considered a service. If you do use an OCPD it has to be sized for the locked rotor current and it has to be located away from the main service equipment (695.4(B)(3)(a)(3):

"Not be located within the same enclosure, panelboard,
switchboard, switchgear, or motor control center, with
or without common bus, that supplies loads other than
the fire pump."

I believe you can make the tap in the switchgear and not somewhere outside the building as long as there's no way to disconnect the service at or before the switchgear.

 

[faresos]

Generally you wouldn't put a breaker on the feeder, since it's considered a service. If you do use an OCPD it has to be sized for the locked rotor current and it has to be located away from the main service equipment (695.4(B)(3)(a)(3):

"Not be located within the same enclosure, panelboard,
switchboard, switchgear, or motor control center, with
or without common bus, that supplies loads other than
the fire pump."

I believe you can make the tap in the switchgear and not somewhere outside the building as long as there's no way to disconnect the service at or before the switchgear.

Thanks for the Reply.

As I have indicated, the fire pump will have two sources; one from LV switchgear and the other is from the generator. I read (695.4(B)(3)(a)(3) but I wasn't much clear about it, does that means we can't power the fire pump from a feeder located within the switchgear of the normal source?

 

[faresos]

One more thing, this doesn't consider to be the main service. The main service is a MV gear located outside the facility.

 

[gadfly56]

Thanks for the Reply.

As I have indicated, the fire pump will have two sources; one from LV switchgear and the other is from the generator. I read (695.4(B)(3)(a)(3) but I wasn't much clear about it, does that means we can't power the fire pump from a feeder located within the switchgear of the normal source?

Short answer is, "no, you can't."

 

[gadfly56]

One more thing, this doesn't consider to be the main service. The main service is a MV gear located outside the facility.

Reading your original post, I wondered about that. I'm guessing you need at least one transformer to drop down to the operating voltage. Are there any disconnects or OCPD's in the path back to the MV gear?

 

[faresos]

Reading your original post, I wondered about that. I'm guessing you need at least one transformer to drop down to the operating voltage. Are there any disconnects or OCPD's in the path back to the MV gear?

Yes. the primary source for the fire pump is coming from one of many substations within the building, the substation has 3000KVA step down transformer and 4000A switchgear with multiple feeders breakers. One of those feeder breakers will be feeding the fire pump. The second source of the fire pump is coming from a dedicated circuit breaker at the generator. So I guess you think per 695.4(B)3.a.3 the feeder breaker can't be within the switchgear.

 

[gadfly56]

Yes. the primary source for the fire pump is coming from one of many substations within the building, the substation has 3000KVA step down transformer and 4000A switchgear with multiple feeders breakers. One of those feeder breakers will be feeding the fire pump. The second source of the fire pump is coming from a dedicated circuit breaker at the generator. So I guess you think per 695.4(B)3.a.3 the feeder breaker can't be within the switchgear.

That's the way I see it. And both breakers need to be sized for the locked rotor current. They are also the ONLY disconnects allowed in the path to the controller per 695.4(B)(1), with some exceptions.

 

[augie47]

devils advocate here...'
IF the install qualifies under 695.3(C), multi-building campus style complex, I don't see the requirement for separate sections.

 

[gadfly56]

devils advocate here...'
IF the install qualifies under 695.3(C), multi-building campus style complex, I don't see the requirement for separate sections.

Yeeesh, there you go reading the code and all. :lol: True enough, but in this particular case I don't believe he has a multi-building campus going on. And if he does, it looks like he'd be under the (2) & (3) portion which would still point you to 695.4(B) where the additional means are permitted only to comply with other parts of the Code. If not required, I read that as not permitted.