We have been contracted to 'modernize' a large government building, and the existing power distribution baffles me...
*(6) 13.75kV utility feeders routed through 4 transformer vaults
*23 transformers within the 4 transformer vaults, each with primary and secondary OCP, utility meter for each transformer, each tap random primary feeders to balance the load
*transformer secondaries bussed together by the section of the building they serve
*all equipment within the transformer vaults are owned and maintained by the utility company
*the secondary conductors are routed to 26 switchboards throughout the facility
Questions:
There are no service entrance disconnects on the secondary feeders outside of the transformer vaults. The OCP is considered to be at the associated switchboard, which could be hundreds of feet away.
1. Is this legal in a government building? Do we hold goverment buildings to NEC requirements, or are they their own jurisdiction?
2. The secondary feeder neutrals are sized at 50% of the NEC required size. Is this something that should be fixed, even though they have never had any power problems?
Also, the facility has no way of disconnecting power to the building other than calling the local utility and having them come out and switch all 23 transformer secondaries. They would like the capability of disconnecting power themselves.
3. Any suggestions?
P.S...no ground fault protection anywhere in the building...
*(6) 13.75kV utility feeders routed through 4 transformer vaults
*23 transformers within the 4 transformer vaults, each with primary and secondary OCP, utility meter for each transformer, each tap random primary feeders to balance the load
*transformer secondaries bussed together by the section of the building they serve
*all equipment within the transformer vaults are owned and maintained by the utility company
*the secondary conductors are routed to 26 switchboards throughout the facility
Questions:
There are no service entrance disconnects on the secondary feeders outside of the transformer vaults. The OCP is considered to be at the associated switchboard, which could be hundreds of feet away.
1. Is this legal in a government building? Do we hold goverment buildings to NEC requirements, or are they their own jurisdiction?
2. The secondary feeder neutrals are sized at 50% of the NEC required size. Is this something that should be fixed, even though they have never had any power problems?
Also, the facility has no way of disconnecting power to the building other than calling the local utility and having them come out and switch all 23 transformer secondaries. They would like the capability of disconnecting power themselves.
3. Any suggestions?
P.S...no ground fault protection anywhere in the building...