Master Electrician Exam (NEC)Services, Feeders, and Branch CircuitsHard
A commercial building has a 600A, 480Y/277V, 3-phase, 4-wire service. The service equipment includes a main service disconnect and an individual meter socket. Which of the following is considered a service point?
- AThe utility side terminals of the meter socket.
- BThe point of connection between the utility supply and the premise wiring.
- CThe point where the service entrance conductors enter the service equipment.
- DThe load side terminals of the main service disconnect.
Show answer & explanationAnswer & explanation
Correct answer: B. The point of connection between the utility supply and the premise wiring.
According to NEC Article 100, the 'Service Point' is defined as the point of connection between the facilities of the serving utility and the premises wiring. This is distinct from the service entrance conductors or the service equipment itself.
Why the other options are wrong
- A. The utility side terminals of the meter socket is generally the service point, as it is where the utility's conductors connect to the premise wiring's meter equipment, but the definition is broader.
- C. This describes the entry point of service conductors into the building or equipment, not necessarily the service point itself, which is the demarcation with the utility.
- D. The load side of the main service disconnect is part of the premises wiring, after the service point.
Service Point (NEC Article 100)
The point of connection between the facilities of the serving utility and the premises wiring system, marking the demarcation of responsibility between the utility and the building owner's electrical system.
- Demarcation point between utility and premises wiring.
- Defined in NEC Article 100.
- Important for determining service vs. feeder rules.
Memory trick: Service Point: 'Utility's Handshake' with 'Premises Wiring'!