Electrical work isn’t always strictly electrical work. This becomes obvious when, for example, you need to replace a 100 HP motor. That job involves a great deal of mechanical skill, just for the alignment aspect. Keep this in mind when doing lockout/tagout.
In addition to locking out electrical sources, you may need to lock out or neutralize several mechanical sources of energy. These source many not be readily apparent. Find them by looking through equipment manuals (which often describe the sources prescribe safety practices for them), piping and installation drawings (P&IDs), and other documentation for the equipment under question.
Disabling some non-electrical energy sources:
- Hydraulic fluids. Open valve to release pressure. Example: Hydraulic press lines to a solenoid you’re replacing.
- Weights. Use blocks to occupy movement space, straps to restrict movement, or lower to bottom position. Example: Hydraulic press ram, which is raised above where you must stand to replace light curtain wiring.
- Pneumatic systems. Open valve to bleed system. Example: Pneumatic arm that can shoot into the space where your head will be when you’re replacing a servo motor.
Also, beware of:
- Springs. Disconnect to release tension.
- Chemical. Wear PPE, follow valve out procedure.
- Thermal. Wear PPE, follow cooling procedure.
