Report Text: Background – During a previous refit, a new radar had been installed on board. During installation, all old wiring has been removed and replaced by new cables. The new system has been installed by a Servicing Company.
Accident – Because the cables were too long, slack had been left behind the chart shelf. Unfortunately the slack had not been secured and, during many years of the shelf being moved in and out, a shearing force had been applied to the 12 volt cables. This finally resulted in a short circuit which burnt the cable before the fuse went, as shown in the photograph:
Further investigation disclosed another cable from the radar installation being partly damaged in the same way by the same shelf. This was the 220 volt power supply. A short circuit on this cable could have lead to an electrical fire on the bridge, causing major damage to the vessel.
Remedial action: After the wiring had been repaired, the following countermeasures were applied:
1) All radar wiring was checked for any kind of damage.
2) Slack in the cables has been picked up and the cables have been secured by cable ties.
3) Other bridge equipment has been checked for slack cables and signs of wearing.
Lessons learned: The work of service teams must be checked. It is strongly advised that service engineers carrying out such installations should be accompanied by an appropriate member of the ship personnel.
As the reporter has correctly identified, the incorrect installation of the cables could have resulted in a major fire. This highlights the importance of having and implementing a good procedure in the ship’s Safety Management System regarding changes to the vessel’s equipment and systems. This should include, risk assessment, planning of the work and supervision.