Consider a large industrial complex with multiple buildings. According to the 2002 NEC, what is the proper location for the disconnecting means for the eight 3,000A feeders that are installed between the eight 2,500kVA substation, 480V secondaries located outdoors, and the eight 3,000A, 480V switchgear(s) located in the electrical room(s) inside one of the facility's buildings?
A) The disconnecting means shall be located at the nearest point of entrance (of the feeder conductors) into the building.
B) There shall be only one disconnecting means for this installation, which must be located as written in answer A).
C) There may be multiple disconnecting means for this installation. However, all disconnecting means must be grouped together in one location.
D) The disconnecting means may be located remotely from the electrical equipment it serves or at the nearest point of entry of the feeder conductors into the building if the facility has qualified persons to maintain the installation along with established and maintained documented safe switching procedures.
Explanation: As written in 225.32 of the NEC, "the disconnecting means shall be installed either inside or outside of the building or structure served or where the conductors pass through the building or structure. The disconnecting shall be at a readily accessible location nearest the point of entrance of the conductor.
"Exception No. 1: For installations under single management, where documented safe switching procedures are established and maintained for disconnection, and where the installation is monitored by qualified individuals, the disconnecting means shall be permitted to be located elsewhere on the premises."
Owen is the owner and president of National Code Seminars and the holder of master electrician certifications in 46 states.