ECN Forum Forums Code Related Discussion NEC & other Code issues Fire Pump Transfer Sw.

I concur.

Guys
Sounds good but can't be done. Why As I Stated before '
#1 Generator has Several breakers at it one feeds Fire Pump Transfer Switch other feeds 4 pole to Bld loads. SO Generator MUST be bonded at ist Breaker.
#2
Fire Pump transfer switch is Fed from the NORMAL power source straight from the transformer THUS MUST be bonded at ist disconect(Transfer switch).
So again Three Phases and a Equipment Gr. comes from Generator is Right.
So in Firepump transfer switch you have From Generator 3 phases and Equipment gr.
From Service 3 phases and Neutral. I feel there NO Way with this set up it can be hooked up to code the way its set up.

So Yooper- Your back to a 4-pole transfer switch.

Except all units are IN PLACE . Fire Pump 3 pole Transfer switch.Its at a Casino Soooooooooooo .

How are the neutrals handled in the other transfer switches? I don't see a problem with parallel neutral & ground current depending on what other services the transformer is feeding and how the neutrals are handled in those transfer switches. Wouldn't you be okay if the other transfer switches were all 4-pole or had no neutral either? That way neutral current wouldn't find a return path back to the transformer neutral if it ventured up the equipment ground back to the generator because that neutral is isolated. If that generator neutral has a permanent bond to the transformer neutral elsewhere, then you've got a problem.

[This message has been edited by Jps1006 (edited 09-30-2006).]

Yoopersup, why *must* you bond the neutral at the generator? So long as you're not switching the neutral at the breaker, exception 1 would allow you to bond the neutral at the transfer switch instead of the generator & the neutral bus would still be contiguous and feed the other circuits, and no multiple grounds. It's legal and electrically sound.

Electrically, it really doesn't matter where the neutral is bonded, just so long as it's electrically contiguous. Sure, it's best to ground it at the source, but it doesn't have to be.

Unless there are other complications in the design we're not aware of/taking into account?

[This message has been edited by SteveFehr (edited 10-01-2006).]

Steve's correct, 250.30(A)(1) says you can bond a SDS any place from the source to the first disconnecting means, '02 NEC

Look back at Posts . The ist Breaker Is on the Generator! In fact there two Breakers there (ONE feeds Fire pump transfer switch) Break (Second feeds another Building 4 pole transfer switch).There more then one transfer switch involved here.

So if your first disconnect/breaker is at the generator, and we have established that you are running a grounded SDS you are required to install your MBJ at the generator and you will be running 4 conductors to your transfer switch. The equipment ground will be just that and the neutral will be terminated on one of the 4 poles of the transfer switch.

Again Fire Pump transfer Switch Alreay in Place is 3 pole. And Remember you also have a SERVICE coming from another Transformer to the Fire Pump Skid THUS.
Generator Hot Hot hot Ground
Power Co. Hot Hot Hot Neutral
Again FP tranfer switch 3 Pole in Place .
There really NO place for a Neutral in the fire Pump transfer fer Sw. Just Ground Connections. Service pipe comes out of the concrete directly in FP Skid.
Thus 3 phases and Gr. one side Three phase and Neutral other side.