What is the LOTO procedure?
Lock-out tag-out: isolating, locking and proving a circuit dead, so nobody can energise it while people are working.
Lock-out tag-out makes sure a circuit cannot be energised while people work on it. The sequence is: obtain a permit, switch off the CCR, isolate the supply (and any standby CCR or changeover that could feed the same loop) and the output to the series circuit, lock and tag each isolator, then prove dead and earth the circuit before work begins.
The lock physically holds the isolator off, and the tag shows who fitted it and why. Each person working fits their own lock, and only that person removes it. The voltage tester, which must be rated for the circuit voltage, is itself proved on a known live source before and after the dead test, so a faulty tester cannot give a false “dead”. Switching off at a control panel is never enough, because control can come from the local, remote or tower position.
Frequently Asked Questions
Q1What does LOTO mean?
Lock-out tag-out. Equipment is isolated from every source of energy, each isolation point is fitted with a personal lock and an identifying tag, and the circuit is proved dead before work begins.
Q2Why is LOTO needed on AGL circuits?
A CCR drives current through a series circuit, so the output can be hazardous even when the load looks small. Control can also come from local, remote or tower positions, so a lock is needed to stop anyone energising the circuit while people are working on it.
Q3What is the difference between the lock and the tag?
The lock physically holds the isolator in the off position. The tag shows who fitted the lock, why and when. A tag on its own does not stop the isolator being switched on.
Q4Is switching off at the control panel enough?
No. A control command can be reset or sent from another position. The supply must be isolated at the isolator, locked and tagged, and the circuit proved dead before work starts.
Q5Who removes the lock?
The person who fitted it, once their work is finished and the circuit is confirmed safe to restore. Each person working on the circuit fits their own lock, so the circuit stays isolated until every lock is off.
Q6What if the person who fitted a lock is not available?
Nobody else removes another person’s lock on their own. The site procedure sets a formal lock-removal process, led by a named authorised person, which confirms the owner has left site or cannot be reached, that the circuit is safe to restore and that the owner is told before they next return to work.
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