Electrical power should always be shut off at the service disconnect or entrance panel when installing equipment. What is the correct term for this shut-off point?

Electrical power should always be shut off at the service disconnect or entrance panel when installing equipment. What is the correct term for this shut-off point?

• A. Service Disconnect
• B. Breaker Panel
• C. Subpanel
• D. Junction Box

Answer: (A)

Disengaging all power at the point where the utility service enters the building is essential for safely servicing equipment. That shut-off point is called the service disconnect. It is the device designed to disconnect the incoming service conductors from the building’s electrical system, effectively cutting power to everywhere in the facility. This differs from a breaker panel, which houses the individual breakers for branch circuits; a subpanel is a secondary panel fed from the main panel; and a junction box is simply a container for wire splices and does not provide a means to shut off power to the entire system. Some installations place the main disconnect inside the service panel, while others use a separate switch or device at the service entrance. Always verify power is off before work.

Disengaging all power at the point where the utility service enters the building is essential for safely servicing equipment. That shut-off point is called the service disconnect. It is the device designed to disconnect the incoming service conductors from the building’s electrical system, effectively cutting power to everywhere in the facility.

This differs from a breaker panel, which houses the individual breakers for branch circuits; a subpanel is a secondary panel fed from the main panel; and a junction box is simply a container for wire splices and does not provide a means to shut off power to the entire system. Some installations place the main disconnect inside the service panel, while others use a separate switch or device at the service entrance. Always verify power is off before work.