NEC 250.146(D) / high-rise office Electrical Plans

NEC 250.118 / 250.122 / 406.4(C)

Even though UF cable includes a grounding conductor, if individual conductors are run in conduit underground, an equipment grounding conductor of a recognized type must be included and sized with the circuit so the receptacle has an effective ground-fault current path.

NEC 250.118 / 410.44

Suspended ceiling support wires and grid members are not listed as equipment grounding conductors. A separate equipment grounding conductor or grounding path must be provided for all lighting fixtures.

NEC 250.118(5)

Flexible metal conduit over 6 feet in length requires an equipment bonding jumper. Even under 6 feet, the FMC connections must provide a reliable ground path, and many jurisdictions require a bonding jumper regardless of length.

NEC 250.32(B)

This is correct. In a sub-panel (whether in the same building or a separate structure with a 4-wire feeder), the neutral must be isolated from the equipment grounding conductor and the enclosure. Bonding neutral to ground at a sub-panel creates parallel paths for return current, which can put current on metal parts and create shock hazards. The bonding is done only at the main panel (service equipment).

NEC 250.53(D)(2)

A metal underground water pipe electrode must be supplemented by an additional grounding electrode. It cannot serve as the sole grounding electrode because plastic pipe repairs can interrupt the path.

NEC 250.64(C)

Grounding conductor splices must use listed connectors such as split bolts, compression connectors, or exothermic welds. Electrical tape alone is not a listed grounding connection method.