This is a pet peeve of mine: DETAILS MATTER in safety procedures and safe work practices. One thing we commonly find is some very generic language in LOTO procedures for how to verify each energy source has been isolated and is at a Zero Energy State (ZES). For example, you’re performing a “periodic inspection,” and during the inspection, you observe the worker throw the disconnect to the off position, apply their lock, and return to the machine, where the procedure states, “attempt to start the machine using the Start Button.” But the “start button” is actually a button on an HMI screen, which is now blank since the electrical power has been turned off.
Is this procedure accurate enough for you?
Would you accept a blank/dark HMI screen as a means to verify the electrical is at a ZES?