USCG Exam PracticeSwitchboards and distribution systems
Under 46 CFR §111.05-17, which of the following correctly describes the grounding arrangement for an emergency power generation system neutral?
- A. The neutral must be directly grounded at the emergency switchboard with a fuse in the neutral conductor
- ✓ The neutral must have no direct ground at the emergency switchboard, and the neutral bus must be permanently connected to the main switchboard neutral busCorrect
- C. The neutral must be grounded at both the emergency switchboard and the main switchboard simultaneously
- D. The neutral must be grounded at the emergency switchboard through a circuit breaker to allow isolation
Why B is correct
46 CFR §111.05-17(a)(1) and (2) require that the emergency system neutral have no direct ground connection at the emergency switchboard, and that the neutral bus be permanently connected to the neutral bus on the main switchboard. A circuit breaker, switch, or fuse in the neutral bus-tie conductor is also prohibited.
Cited:46 CFR §111.05-17