What is a service disconnect?

• A. The main disconnect that interrupts incoming service to the building.
• B. A subpanel in the basement.
• C. A device that protects a single circuit from overload.
• D. A temporary switch used during construction.

Answer: (A)

The service disconnect is the main switch or breaker that can shut off all electrical power coming into the building at the service point. It interrupts the incoming service, not just one circuit. It’s not a subpanel, which is simply a secondary panel that distributes power to part of the building. It’s not a device that protects a single circuit—that role belongs to a branch-circuit breaker. And it isn’t a temporary switch used during construction. In many installations, it’s a main breaker in the main panel or a separate outside disconnect located where the service enters, and it must be readily accessible to shut off power to the entire building.