Dedicated transformer for fire pump

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lilsparky

Member
Location
Madison, Al
Hello everyone,
I am upgrading a building that previously didn't have any fire protection. There isn't a generator onsite and to comply with NEC I have to install a dedicated service to the fire pump. The service will come from a 12.47kv pole to an outdoor pad mounted 12.47kv-480v transformer before entering the building.

There will be 100 hp fire pump @480v, 3ph and a 2hp jockey pump @480v 3ph. I know per my calculations, the min. size the transformer should be is 150kva. However the code states that there needs to be a disconnect switch for primary OCD ahead of the transformer. My question is how do I do that if I'm coming off of a utility pole? Do they make disconnects within an outdoor transformer enclosure.?

This is the first time I'm doing a building without a backup generator onsite.
 
T

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
lilsparky said:
Hello everyone,
I am upgrading a building that previously didn't have any fire protection. There isn't a generator onsite and to comply with NEC I have to install a dedicated service to the fire pump. The service will come from a 12.47kv pole to an outdoor pad mounted 12.47kv-480v transformer before entering the building.

There will be 100 hp fire pump @480v, 3ph and a 2hp jockey pump @480v 3ph. I know per my calculations, the min. size the transformer should be is 150kva. However the code states that there needs to be a disconnect switch for primary OCD ahead of the transformer. My question is how do I do that if I'm coming off of a utility pole? Do they make disconnects within an outdoor transformer enclosure.?

This is the first time I'm doing a building without a backup generator onsite.
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I think 695.3(A)(1) applies for this. You just need to have the POCO furnish a service capable of carrying the lock rotor current indefinitely. I don't think 695.5 applies here, as that would be if the transformer was part of a feeder as opposed to a service.
 
bob

bob

Senior Member
Location
Alabama
lilsparky said:
The feeder services are coming from outside the building. Is that your question?
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No. Will the service be considered outside of the building? If they are in conduit and encased in concrete, they are considered outside of the building and are service conductors. No need for disconnect or over current protection. The disconnect is at the fire pump controller.


http://www.mikeholt.com/mojonewsarchive/NEC-HTML/HTML/Article695FirePumps~20030103.htm

http://ecmweb.com/content/abcs-fire-pump-installations
 
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lilsparky

Member
Location
Madison, Al
The service will be coming from outside. Is it code requirement to encase the feeders from the secondary side of the transformer to the fire pump? This is a really remote area. I didn't see that in the code.

This will be a customer owned transformer and power pole.

This power is solely dedicated to the fire pump and it's accessories. The power pole will feed another transformer that will service the other building loads
 
T

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
lilsparky said:
The service will be coming from outside. Is it code requirement to encase the feeders from the secondary side of the transformer to the fire pump? This is a really remote area. I didn't see that in the code.

This will be a customer owned transformer and power pole.

This power is solely dedicated to the fire pump and it's accessories. The power pole will feed another transformer that will service the other building loads
Click to expand...

Sorry, in my comments in post #6, I was under the impression that this would be POCO supplied directly to the fire pump controller. Yes, your situation does change things.
 
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