Finger burnt by overheating electrical component

What happened?

The Marine Safety Forum (MSF) reports an incident in which a worker on a vessel was working on the operating panel for a 690 VAC anti-heeling  pump, when he received a burn to his middle finger; he got burnt when he reset the breaker switch.  This resulted in a first aid case and he was treated on board.

What went wrong?  What were the causes?

It was noted that:

  • No work or maintenance was being carried out on the inside of the cabinet, so there was no permit to work or isolation (the breaker was the method of isolation);
  • The breaker was never ‘live’ – the burn was due to the heating of the breaker due to it being of an incorrect rating. This was confirmed afterwards through numerous simulations and calculations.

The MSF member noted the following causes:

  • Rotary isolation switch within the electrical cabinet was broken and had been removed;
  • There had been a failure to follow defect reporting procedure;
  • Due to a missing isolation switch, direct contact had to be gained internally to reset breaker;
  • There was a lack of hazard awareness and risk perception;
  • There was a lack of consideration for safety devices.

What actions were taken?  What lessons were learned?

  • A new rotary isolation switch was fitted to the breaker switch;
  • All similar cabinets on board were checked and rotary switches fitted as required;
  • A full onshore investigation was initiated due to the perceived potential severity of the incident;
  • Upon further investigation, it was found that a change in the cable length after the cabinet from the system design to actual build meant that the breaker was insufficient and had a tendency to heat up. This cable was also replaced.