USCG Exam PracticeSwitchboards and distribution systems
Under 46 CFR §111.05-17, which of the following correctly describes the grounding arrangement for the neutral of an emergency power generation system?
- A. The neutral must be directly grounded at the emergency switchboard and isolated from the main switchboard neutral bus.
- ✓ The neutral must have no direct ground at the emergency switchboard, and the neutral bus must be permanently connected to the main switchboard neutral bus.Correct
- C. The neutral must be grounded at both the emergency switchboard and the main switchboard simultaneously.
- D. The neutral must be grounded through a fuse at the emergency switchboard to protect against fault current.
Why B is correct
46 CFR §111.05-17(a)(1) and (2) require that the emergency system neutral have no direct ground at the emergency switchboard and that its neutral bus be permanently connected to the main switchboard neutral bus. A direct ground at the emergency switchboard and simultaneous dual grounding are both prohibited by this section.
Cited:46 CFR §111.05-17