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The Safety Check Before You Start Checklist

Reference Checklists Updated Jul 29, 2026

Why this matters

Most serious field injuries trace to stored or live energy that someone assumed was off. "I flipped the breaker" is not the same as "I verified it is dead," and the gap between the two is where the arc flash, the scald, and the crushed hand happen. This card is the isolate-and-prove discipline you run on every energy source before a tool touches the equipment. Run it even when you are behind; behind schedule is recoverable, an injury is not. For the broader site scan (PPE, footing, pets, kids, the customer brief) see the job-site safety checklist.

Phase 1: Personal and scene, before you approach

Fast, but do not skip it. Most of these take seconds and prevent the injury that is not about energy at all.

  • PPE matched to the work is on before you approach: eyes, hands, and the task-specific gear (dielectric, chemical, respiratory).
  • Footing is clear and stable; move trip hazards and set any ladder on solid, level ground before you climb.
  • You know your exit and where the nearest water, extinguisher, and phone are.

Phase 2: Isolate every energy source

Turning it off at the equipment is not enough. Isolate at the source and take control of it so no one else can restore it.

  • Electrical: open the disconnect or breaker feeding the work, then lock and tag it so no one can re-energize it while you are inside.
  • Gas or fuel: close the appliance shutoff, and for anything beyond a quick check, the upstream valve as well.
  • Water and pressure: close the supply, then open a downstream point so the line is not still under pressure when you break a connection.
  • Stored mechanical energy: block, pin, or lower anything spring-loaded, suspended, or under tension (a garage door, a raised platform, a loaded actuator).
  • Capacitors and stored electrical charge: treat as live until discharged per the equipment's procedure, even after the power is off.

Phase 3: Prove it is actually dead

An isolation you did not verify is a guess. Prove zero energy before the first tool goes in.

  • Test the circuit dead with a meter or tester, then re-test on a known live source to confirm the tester still works (live-dead-live).
  • Confirm the gas or fuel valve actually holds: watch the gauge or the pilot, do not trust the handle position.
  • Verify pressure reads zero at the bleed point, not just that you closed the supply valve.
  • Confirm moving parts cannot start: attempt the control once with the isolation in place.

Phase 4: The environment before you enter

The space itself can be the hazard, especially where air does not move.

  • Confined space (attic, crawlspace, closed mechanical room): ventilate and use a gas monitor before entry on any combustion, refrigerant, or solvent work.
  • No running engines, open solvents, or combustion in an unventilated space you are about to occupy.
  • Tell the customer you are starting and that they must not touch controls, breakers, or valves until you say the job is done.

References

  • OSHA 29 CFR 1910.147, The Control of Hazardous Energy (lockout/tagout)
  • NFPA 70E, verifying an electrically safe work condition before contact
  • See related: Job-Site Safety Checklist
  • Trade-standard practice for isolate-and-verify before service

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