CSLB C-10 Electrical ContractorSafety and TestingEasy
A qualified electrical worker is preparing to perform maintenance on a 480V motor control center. After de-energizing the equipment and verifying absence of voltage, what is the NEXT critical step according to NFPA 70E before beginning work?
- AApply insulating blankets to adjacent energized parts.
- BInstall personal protective grounds on the conductors.
- CRe-energize the equipment to confirm proper lockout/tagout.
- DBegin the scheduled maintenance tasks.
Show answer & explanationAnswer & explanation
Correct answer: B. Install personal protective grounds on the conductors.
After de-energizing and verifying absence of voltage, the next critical step in establishing an electrically safe work condition (ESWC) is to install personal protective grounds where there is a possibility of induced voltage or accidental re-energization.
Why the other options are wrong
- A. Applying insulating blankets is a protective measure, but grounding is a more fundamental step after verifying absence of voltage to address potential re-energization or induction.
- C. Re-energizing the equipment at this stage would defeat the purpose of establishing an electrically safe work condition and is not a step in the process.
- D. Beginning work prematurely without grounding could expose the worker to hazards if the circuit becomes re-energized or induced voltages are present.
Personal Protective Grounds
Temporary conductive connections applied to de-energized conductors to protect workers from electric shock due to accidental re-energization or induced voltages.
- Applied after verifying absence of voltage.
- Connects conductors to earth ground and often to each other.
- Essential for establishing an electrically safe work condition (ESWC).
Memory trick: De-energize, Verify, Ground, Work Safe!