Fire Pump??

[bdarnell]

would I be allowed to provide a tap in the utility co Pad mount, (being that the CT's are there i would see no reason why they would not allow) and enter the building via undergroung conduit directly to the transfer switch and firepump controller (still sized for locked rotor).

That's a utility call, but I see no reason why not, provided that they allow the number of secondary conductors that you propose on their bushings. We do it all the time.

would this arrangement require a disconnect/overcurrent protection?

Not until you enter the building. Under the slab is not in the building.

 

[PT]

Can't the existing feeder accommodate the new fire pump. It's only the overcurrent protection that you will be sized according to its locked-rotor. The conductors can be sized using 125% of fire pumps full-load current.

NEC 6295.6(C) Conductor Size.
(1) Fire Pump Motors and Other Equipment. Conductors supplying a fire pump motor(s), pressure maintenance pumps, and associated fire pump accessory equipment shall have a rating not less than 125 percent of the sum of the fire pump motor(s) and pressure maintenance motor(s) full-load current(s), and 100 percent of the associated fire pump accessory equipment.
(2) Fire Pump Motors Only. Conductors supplying only a fire pump motor(s) shall have a rating not less than 125 percent of the fire pump motor(s) full-load current(s).

If the feeder is not adequate, you can ask the inspector if it is allowed that you apply an automatic load shedding in the event that the fire pump operates. Load shedding is allowed in the generator capacity.

NEC 695.3(B)(1) Generator Capacity. An on-site generator(s) used to comply with this section shall be of sufficient capacity to allow normal starting and running of the motor(s) driving the fire pump(s) while supplying all other simultaneously operated load. Automatic shedding of one or more optional standby loads in order to comply with this capacity requirement shall be permitted. A tap ahead of the on-site generator disconnecting means shall not be required. The requirements of 430.113 shall not apply.

 

[Polarcat]

the feeder is def. large enough, however the tap would have to be before the main disconnect and not in the same enclosure, that is what my problem is (would have to provide an additional JB ahead of the gear and it wouldn't be cheap or practical).