Equipment starts unexpectedly

What happened

THree mechanics obtained a Lock-out/Tag-out (LOTO) for a High voltage AC unit, and were performing routine maintenance on the unit. As one of them went to lubricate the bearings, the machine started unexpectedly. Work was stopped and a review was conducted. It was discovered that a linkage was broken in the circuit breaker handle and the breaker did not actually shut off when arranging the LOTO. The plant electricians repaired the linkage, the LOTO was rehung, and the work was completed.

What went right and/or wrong?  

• What went right: no one was in the line of fire when the machine restarted and there were no injuries;
• What went wrong: equipment failure – the linkage in the breaker handle was broken.

Lessons learned

• Carefully check that equipment is de-energized before working on it – prove that it is “dead”;
• Ensure a full and thorough understanding of isolation and ensure the proper sources of energy are isolated when equipment is upgraded or modified.

IOGP Life-Saving Rules applicable

• Energy Isolation: the mechanics did not:
  • Identify all energy sources;
  • Confirm that hazardous energy sources were isolated, locked, and tagged;
  • Check there was zero energy; did not test for residual or stored energy.
• Work Authorisation: the mechanics did not:
  • Confirm that hazards were controlled or that it was safe to start

Members may wish to refer to:

• LTI: person crushed in watertight door
• Serious injury caused by energy isolation failure
• Agitator started moving during mud tank cleaning – leading to injury