Near-miss: Inadequate insulation of 690V bus bars

The 690V switchboard had been isolated for a survey, and the panels were opened for inspection. It was observed that not only had the breakers been removed, but the bases had also been removed leaving exposed bus bars. It was also noted that the wire terminations were not fully insulated. The bus bars would be live when the switchboard is in its normal condition, and they have a degree of flexibility, so it is feasible that as they move with vessel vibration they could arc, causing significant damage and injury to personnel if they were present in the area.

• Nearly three years previously, two further incidents had occurred in which there were significant breaker failures on the vessel 690V switchboard which had resulted in serious injury to personnel. Short term remediation work had been carried out at that time, and a survey for long term rectification works was being carried out prior to a maintenance period.
• During this survey it was noted that there were blanks on the switchboard panel where breakers had been removed. The missing breakers supply power to a tensioner that is currently not installed. The unused tensioner breakers had been removed to be used in other areas as the vessel had insufficient spares onboard to replace all the breakers impacted by the breaker failure. They were relocated some time ago with the vessel technical management being aware of this.
• Subsequent to the initial failure and prior to the most recent survey this switchboard had undergone a full health care check by a third party which also failed to identify these discrepancies.
• There was no check made to ensure that the third party contractor’s work was carried out in a satisfactory manner.
• Spare parts were not effectively managed onboard, with parts removed as necessity at the time not being replaced.
• A management of change process was not used when the breaker and base were initially removed.