USCG Exam PracticeSwitchboards and distribution systems
Under 46 CFR §111.05-17, the neutral of an emergency power generation system must be grounded in which manner?
- A. With a direct ground connection at the emergency switchboard and no connection to the main switchboard neutral bus
- ✓ With no direct ground at the emergency switchboard, the neutral bus permanently connected to the main switchboard neutral bus, and no switch, breaker, or fuse in the bus-tie neutral conductorCorrect
- C. With a direct ground at the emergency switchboard and a fused connection to the main switchboard neutral bus
- D. With no direct ground at the emergency switchboard and a circuit breaker in the bus-tie neutral conductor to allow isolation during testing
Why B is correct
46 CFR §111.05-17(a)(1)-(3) sets three simultaneous requirements for the emergency system neutral: no direct ground at the emergency switchboard, permanent connection of the neutral bus to the main switchboard neutral bus, and no switch, circuit breaker, or fuse in the bus-tie neutral conductor.
Cited:46 CFR §111.05-17