What condition allows a disconnector to function as a switch?

A disconnector can function as a switch when it is rated for switching under load. This rating indicates that the device has been specifically designed and tested to safely interrupt the current while it is flowing through the circuit. Such devices ensure that the disconnection happens without causing dangerous arcs or faults, which could lead to equipment damage or hazards.

In contrast, while manually controlled devices can be operated like switches, their ability to safely disconnect an active circuit under load depends on their design specifications. Similarly, disconnectors designed for power failure or those with an automatic reset do not inherently provide the necessary ratings for load switching; these features focus on operational functionality unrelated to current interruption capabilities during active load. Thus, the rated switching capacity under load is what legitimizes a disconnector's use as a switch.