What are the typical steps in a substation switching procedure after de-energizing?

• A. Verify zero energy, apply clearance, verify isolation and interlocks, issue permit, perform switching, verify clearance again, re-energize.
• B. Immediately re-energize after loosening interlocks.
• C. De-energize and leave unspecified.
• D. Keep interlocks engaged and perform switching.

Answer: (A)

After de-energizing, the priority is to ensure that the circuit is truly dead and remains safe while work is prepared and performed. Start by confirming zero energy with appropriate test instruments and a second verification if required, so there’s no residual voltage or stored energy. Then apply clearance (lockout/tagout) to physically prevent re-energizing and to protect workers, ensuring all sources and access points are secured. Next, verify isolation and interlocks are in the proper state so the system cannot be re-energized inadvertently during switching. A work permit is issued to authorize the switching task and document the controls, boundaries, and safety considerations. With the permit in place, perform the switching actions as planned. After switching, re-check clearance to confirm that the area remains clear and that the equipment stays isolated as intended. Only then re-energize, once all checks are complete and the permit is properly released.