In the off position, a switching device must completely disconnect which conductors?

In the context of the operation of a switching device, it is critical that when the switch is in the off position, it effectively isolates the system from voltage sources to ensure safety and prevent electrical hazards. The requirement to completely disconnect all ungrounded conductors is essential because these conductors carry the live voltage. If they are not disconnected, there remains a risk of electrical shock or equipment damage, as they can still present a potential difference that could energize components downstream.

This means that disconnecting only the grounded conductors (which are typically at earth potential) is insufficient for guaranteeing safety, as those conductors may not carry current under normal circumstances. Therefore, the importance of ensuring that all ungrounded conductors are disconnected in the off position stands out as a key safety standard in electrical systems. This practice mitigates the risks associated with accidental contact and ensures the safe maintenance and operation of electrical equipage.