Which best describes the state of an electrical circuit when the isolator switch is engaged?

When the isolator switch is engaged, it serves the primary function of disconnecting the electrical circuit from the power source. The isolator switch is a safety device used to ensure that electrical equipment can be safely serviced or maintained without the risk of electrical shock or other hazards. When engaged, the circuit is effectively inactive, meaning that there is no current flowing, and the equipment connected to the circuit is not operational. This disconnection is critical in maintenance scenarios to protect personnel and equipment.

Understanding this function is essential for safe electrical practices, as it allows for the removal of power while work is being performed on the circuit or connected devices. Engaging the isolator switch is a common procedure before conducting any electrical maintenance work, confirming that the equipment is not only turned off but also entirely isolated from electrical power.