CSLB C-10 Electrical ContractorSafety and TestingMedium
A qualified electrical worker is decommissioning a 600V motor control center. After de-energizing the equipment and applying lockout/tagout devices, what is the next critical step before beginning work, according to NFPA 70E?
- AInstall temporary protective grounding equipment.
- BSign the lockout/tagout permit and begin the work.
- CVisually inspect the work area for any remaining hazards.
- DTest for the absence of voltage on all phases and conductors.
Show answer & explanationAnswer & explanation
Correct answer: D. Test for the absence of voltage on all phases and conductors.
After de-energizing and applying LOTO, the next critical step in establishing an electrically safe work condition, as per NFPA 70E, is to verify the absence of voltage using a properly rated test instrument. This confirms the circuit is indeed de-energized.
Why the other options are wrong
- A. Installing temporary protective grounds is done AFTER verifying absence of voltage, and only if there's a possibility of induced voltage or accidental re-energization.
- B. Signing the permit is an administrative step; work cannot begin until the electrically safe work condition is fully established, including voltage verification.
- C. Visual inspection is part of the overall safety process, but not the immediate critical step after LOTO before touching conductors.
Absence of Voltage Test Sequence
The step in establishing an electrically safe work condition that involves using a test instrument to confirm no voltage is present after de-energization and lockout/tagout.
- Follows LOTO application
- Precedes protective grounding
- Essential for worker safety
Memory trick: SAFE: Stop, Apply, Verify, Establish!