What must not occur until a fault has been cleared after circuit de-energization?

Manual re-closing of breakers should not occur until a fault has been cleared after circuit de-energization because re-closing a breaker while a fault still exists can pose significant safety hazards. If the fault is not resolved, attempting to re-energize the circuit could lead to further damage to the equipment, create dangerous conditions such as electric arcs, and increase the risk of injury to personnel.

Ensuring that a fault has been properly diagnosed and resolved before re-closing the circuit is critical for maintaining electrical safety. This practice follows safety protocols that prioritize the identification and elimination of any hazardous conditions that could undermine safe operation. Moreover, re-closing breakers without addressing existing faults could also disrupt other connected systems or compromise overall system integrity.

In contrast, the other choices typically involve processes that are meant to ensure safety or are part of standard operating procedures that can take place after confirming the absence of faults or hazards in the system. Therefore, the emphasis on clearing faults before any action like manual re-closing is essential for safe electrical work practices.