81. Before any work on electrical or electronic equipment is performed, which of the following precautions should be carried out?

To ensure safety when working on electrical or electronic equipment, secure and tag the supply circuit breaker in the open position to prevent accidental re-energization. This practice involves physically isolating the equipment and implementing lockout/tagout procedures, which are superior to relying on personnel or bypassing safety interlocks. Proper precautions include opening the circuit breaker, securing it to prevent closure, and tagging it to warn others, ensuring a de-energized state and preventing accidental power restoration.