Which of the following best defines 'Safe Isolation' in electrical installations?

Safe isolation is crucial for ensuring the safety of workers when performing maintenance or repairs on electrical systems. The correct choice defines safe isolation as an assurance that circuits are completely disconnected. This means that all electrical sources, including any potential residual voltage, have been effectively turned off and isolated from equipment or circuits. It typically involves multiple steps, including switching off the supply, securing it against accidental re-energization, and using test instruments to verify that the circuit is indeed de-energized before work begins.

This definition emphasizes the critical nature of confirming that there are no live conductors that could pose a risk of electric shock or injury while personnel work on the electrical installation. The processes involved in safe isolation ensures that there is no possibility of the equipment being inadvertently powered during maintenance, which is essential for safety compliance.

In contrast, the other options either lack the necessary components for effective isolation or misrepresent the concept altogether, such as notifying shutdown without ensuring that all connections are safely and completely disassociated from the power sources.