Master Electrician Exam (NEC)Special Occupancies, Equipment, and ConditionsMedium
A master electrician is installing a new wind electric system for a remote cabin. The system includes a wind turbine and associated control equipment. According to NEC, where must a readily accessible disconnecting means be located for the wind electric system?
- AWithin the main service panel of the cabin
- BAt both the wind turbine and at the point of interconnection with the cabin's electrical system
- COnly at the wind turbine tower base
- DOnly at the point of interconnection with the cabin's electrical system
Show answer & explanationAnswer & explanation
Correct answer: B. At both the wind turbine and at the point of interconnection with the cabin's electrical system
NEC Section 694.20 requires disconnecting means for wind electric systems to be provided at both the wind turbine and at the point of interconnection of the wind electric system with the premises wiring system. This ensures safety for both maintenance personnel and emergency responders.
Why the other options are wrong
- A. While the main service panel might contain overcurrent protection, a dedicated, readily accessible disconnecting means is required specifically for the wind system at the interconnection point, separate from just being 'within' the panel.
- C. A disconnect at the tower base is required, but it's not the only location; an additional disconnect is needed at the interconnection point.
- D. A disconnect at the interconnection point is required, but it's not the only location; one is also needed at the turbine.
Wind Electric System Disconnects
The required locations for readily accessible disconnecting means for a wind electric system, as mandated by the NEC, to ensure safety during maintenance and emergencies.
- Required at the turbine.
- Required at the point of interconnection.
- Ensures system can be isolated safely.
Memory trick: Wind turbine and cabin connect, two disconnects, for safety, perfect!