Master Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsMedium
A master electrician is inspecting a marina for compliance with NEC requirements. The marina has several docks with multiple receptacles for shore power. Which of the following is a mandatory requirement for these shore power receptacles?
- AAll receptacles must be rated for at least 50A to accommodate large vessels.
- BReceptacles rated 30A or less must have individual GFCI protection, while those over 30A do not.
- CEach individual receptacle must be protected by an individual overcurrent protective device.
- DEach individual receptacle must be of the locking and grounding type and have GFCI protection.
Show answer & explanationAnswer & explanation
Correct answer: D. Each individual receptacle must be of the locking and grounding type and have GFCI protection.
NEC 555.35(B) requires that all 15- and 20-ampere, single-phase, 125-volt receptacles and all receptacles supplying shore power to boats in marinas and boatyards shall be provided with ground-fault circuit-interrupter protection for personnel. NEC 555.33(A) requires shore power receptacles to be of the locking and grounding type.
Why the other options are wrong
- A. Receptacle ratings vary depending on the shore power requirements of different vessels; not all must be 50A.
- B. All shore power receptacles, regardless of ampere rating, must have GFCI protection (555.35(B)).
- C. While OCPD is required, it's not necessarily 'individual' for each receptacle beyond the standard branch circuit protection.
Marina Shore Power (NEC)
Electrical installations at marinas and boatyards, particularly shore power receptacles, have stringent NEC requirements to protect against electric shock hazards in a wet and potentially corrosive environment.
- All shore power receptacles must be GFCI protected.
- Shore power receptacles must be of the locking and grounding type.
- Overcurrent protection and proper grounding are critical.
Memory trick: Marina Power: Lock it, Ground it, GFCI protect it, or a shock might rock it.