Electrician how-to
How to Verify a Circuit Is De-Energized (Live-Dead-Live)
Never assume a circuit is off. Testing for absence of voltage protects you every time. Follow NFPA 70E and your employer’s procedures.
Never assume a circuit is off. Testing for absence of voltage protects you every time. Follow NFPA 70E and your employer’s procedures. In short: identify; notify; apply, then complete the remaining steps below.
Step by step
Identify all energy sources for the equipment using drawings and labels.
Notify affected people, shut off the equipment and open the disconnect or breaker.
Apply your lock and tag according to the lockout/tagout procedure.
Wear the required PPE and test your meter on a known live source to prove it works.
Test the circuit phase-to-phase and phase-to-ground for absence of voltage.
Retest your meter on the known live source to confirm it still works.
Only then begin work, keeping your lock in place until the job is complete.
Safety reminders for electricians
- Always verify absence of voltage before touching conductors
- Follow lockout/tagout and NFPA 70E arc-flash requirements
- Use ladders and fall protection correctly
- Wear arc-rated PPE, safety glasses and insulated gloves as required
Key terms
Voltage (V) · Current (A) · Resistance (Ω) · Ohm’s law · NEC · GFCI: see the full electrician glossary.