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#201987 07/07/11 05:07 PM
Joined: Mar 2003
Posts: 849
Y
Member
Owner buys power at 24900 so everything on site feeders.
One building requires a Fire Pump.
Its Diesiel Mtr back up on the pump Mtr.( not Generator on that side)
Other side the feed is from 480 volt Building Switchgear (mc cable )fed in Cable tray with other feeders Fused as per Article 430.
Heres where it gets intersting!! The Mcc is fed by a Back up generator.
Since its Acually backed up on both sides,
LRC doesn't apply on Disconnect switch I;d say
(695.4 (b) NEC 2008,
But can the Breaker for the FP controler be in the Switchgear with all the other loads??
Can the cable from the Switch gear be in Cable tray with all the Normal power feeds???(2 hr required fire rateing))
The back up Generator for this building is located remoteley, feeding 4160 to a step dn transformer outside the building (dn to 480)
To make this Correct Where should this Normal feeder (on back up Generator be picked up??
I got a cpl ideas but want see what all you experts out there come up with.

2017 / 2014 NEC & Related Books and Study Guides
Joined: Apr 2002
Posts: 7,283
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Yop:

"But can the Breaker for the FP controler be in the Switchgear with all the other loads??"

I have seen FP feeders in existing gear, as it was allowed some time back (I have been told). The feeder conductors are supposed to be physically barriered from the other conductors within the gear. There are three older whse bldgs in my Twp. that the insurance company is requiring that the FP wiring be brought up to current codes. They were given 120 days to comply, or be dropped for insurance.

"Can the cable from the Switch gear be in Cable tray with all the Normal power feeds???(2 hr required fire rateing))"

Without cracking the book open, I'll vote no; Are you saying that it now has a 2 hr rating?

"To make this Correct Where should this Normal feeder (on back up Generator be picked up??"

My first choice would be to connect on the secondary buss of the xfr, before any OCP, and treat the conductors & raceway as a FP 'service' into the controller/transfer switch.

At the begining of your post you said the FP is dual prime mover, diesel and elec, correct? Am I reading that right? As there are two prime movers for the FP, why the BU genset?

Let's see what other opinions are made.


John
Joined: Mar 2003
Posts: 849
Y
Member
The Whole buildings on backup power, Plus Dieseil Mtr. Backup. Just find the design interesting Yet not code compliant.


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