When a power-operated switch or circuit breaker is used as a service disconnecting means, what must it be capable of during a power supply failure?

When a power-operated switch or circuit breaker is used as a service disconnecting means, it is essential that it can be opened by hand during a power supply failure. This capability ensures that in the event of an emergency or fault condition, personnel can safely disconnect the power manually without relying on the power supply or remote controls which may not function due to the power failure.

This requirement emphasizes safety and accessibility, allowing quick access to disconnect power to prevent hazards such as electrical shock or fire. The design of electrical systems prioritizes the ability for operators to gain manual control of the system to ensure they can respond effectively in critical situations.

In the context of electrical standards and codes, ensuring that service disconnects can be operated manually aligns with safety protocols for both personnel working on electrical systems and for safe maintenance practices.