Master Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsHard
A master electrician is installing a new fuel cell system as a supplemental power source for a commercial building. The fuel cell system is rated at 20 kW. According to NEC, what is the maximum continuous current that a single fuel cell inverter output circuit is permitted to exceed?
- A60 amperes
- B100 amperes
- C30 amperes
- D48 amperes
Show answer & explanationAnswer & explanation
Correct answer: D. 48 amperes
NEC Section 692.10(B) states that the continuous output current of a single fuel cell inverter output circuit shall not exceed 48 amperes. This is a specific limit set for individual fuel cell inverter output circuits, regardless of the overall system size, to manage fault currents and protection.
Why the other options are wrong
- A. 60 amperes exceeds the specific NEC limit for a single fuel cell inverter output circuit.
- B. 100 amperes is significantly higher than the NEC's specified limit for a single fuel cell inverter output circuit.
- C. 30 amperes is too low and not the specified maximum for a fuel cell inverter output circuit.
Fuel Cell Inverter Output Limit
The maximum continuous output current permitted for a single fuel cell inverter output circuit, as specified by the NEC, to ensure safety and proper overcurrent protection coordination.
- Applies to single inverter output circuits.
- NEC Article 692 covers fuel cell systems.
- Helps manage fault currents and protection.
Memory trick: Fuel cell inverter, forty-eight is the max, for safety and code, no relax!