Identifying Energy Sources Toolbox Talk

Lock out tag out only works when every energy source is identified before work starts. On a jobsite, equipment can have more than one source of energy, and some are not obvious. A machine may be shut off but still have stored pressure, raised parts, charged batteries, hot surfaces, springs, or lines that can move without warning.

This talk focuses on how to identify hazardous energy sources before servicing, cleaning, adjusting, repairing, or clearing jams. The crew needs to know what powers the equipment, what energy may still be stored, and what must be isolated before anyone puts hands, tools, or body parts into the danger zone.

Why This Matters

• Unexpected startup can crush, cut, burn, shock, or pin a worker.
• Stored energy can release even after the main power switch is off.
• Missed valves, breakers, batteries, or pressure lines can make a lock out incomplete.
• Identifying all energy sources prevents guessing during maintenance or repairs.
• A good lock out tag out plan starts with knowing exactly what needs to be controlled.

Common Hazards

• Electrical power from panels, cords, generators, batteries, or temporary power feeds.
• Hydraulic pressure in lifts, pumps, skid steers, compactors, or attachments.
• Pneumatic pressure in air lines, compressors, tools, cylinders, and valves.
• Mechanical energy from belts, chains, gears, rotating shafts, springs, and flywheels.
• Gravity energy from raised buckets, suspended loads, elevated platforms, or unsecured parts.
• Thermal energy from hot pipes, heaters, engines, welders, steam, or recently used equipment.
• Chemical energy from fuel lines, gas lines, batteries, tanks, or process piping.
• Stored pressure trapped behind a closed valve, blocked line, capped hose, or clogged fitting.

Safety Checklist

Before Work Begins

• Review the equipment, task, and lock out tag out procedure before starting.
• Identify every power source connected to the equipment, not just the main switch.
• Trace cords, hoses, lines, pipes, and controls back to their source.
• Look for backup power, generators, batteries, capacitors, or automatic controls.
• Check for stored energy in raised parts, pressure lines, springs, flywheels, and heated components.
• Confirm which valves, breakers, disconnects, blocks, pins, or supports are needed.
• Notify affected workers before shutting down or isolating equipment.
• Use the right locks, tags, hasps, blanks, blocks, or restraints for the energy involved.

During Work

• Do not start work until all energy sources have been isolated and controlled.
• Release, bleed, block, restrain, or discharge stored energy before entering the work area.
• Test controls after lock out to confirm the equipment will not start or move.
• Keep locks and tags in place until the work is complete and the area is clear.
• Do not rely on another worker’s lock unless group lock out procedures are being followed.
• Watch for pressure building back up, parts shifting, or equipment settling during the task.
• Stop and reassess if a new hose, wire, valve, panel, or control is found.

Crew Talking Points

• What energy sources are present on the equipment we are working on today?
• Are there any stored energy hazards that may remain after shutdown?
• Who is responsible for locking out each source?
• How will we verify the equipment is fully isolated before work begins?
• What parts could move, drop, rotate, heat up, or release pressure during the task?
• Does anyone see a hidden energy source, unclear control, or condition that needs to be checked before we continue?

Stop Work If

• An energy source has not been identified or controlled.
• The lock out tag out procedure does not match the equipment or setup.
• A valve, breaker, hose, cord, or control is not clearly labeled.
• Stored pressure, raised equipment, or suspended parts cannot be safely released or blocked.
• The equipment moves, starts, cycles, leaks, sparks, or builds pressure after lock out.
• Another crew, trade, or operator may re-energize the equipment by mistake.

Final Reminder

Before any lock goes on, know what energy you are controlling. Find every source, control stored energy, verify isolation, and never assume equipment is safe just because it is turned off.