LOTO Lockout/Tagout
This is the discipline that physically prevents energy from being restored during maintenance and repair. The isolator is locked in the open position and a tag stating who locked it and why is hung on it. The aim is to make it impossible for someone else to restore the energy in good faith.
The core of the practice is this: isolate the energy, lock the isolator, tag it, and verify by measurement that the energy really is cut. This last step is the most often skipped but the most critical one; the locked isolator may be the wrong line.
- Stored energy: electricity is not the only form of energy. Hydraulic pressure, springs, suspended loads and the charge remaining in capacitors must also be released or mechanically secured.
- Personal lock: every worker fits their own lock and only they remove it. If several people are working, a multi-lock hasp is used.
- Verification: after locking, try to start the device and measure the voltage at the terminals.
- Restoring: before energy is restored, the area is cleared, tools are collected and it is verified that everyone has moved away.
In crane and lifting applications, a suspended load is stored energy in its own right. Cutting the electricity does not lower the load; no one works under it until the load is lowered or mechanically supported.
Context in which this term is used: Installation, redundancy and field continuity