Temporary connection to DP system caused short circuit
- DP Event
- Published on 2 November 2017
- Generated on 15 May 2025
- DPE 04/17
- 2 minute read
Undesired event
Connection of any temporary system should be part of a change management plan and risk assessed.
Comments
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Various DP equipment, including the DP status lights, were connected via UPS No.2. Investigation found that the UPS tripped because of a break in the portable cable supplying the DP status lights to ROV control.
- The vessel does not have a permanent ROV system, when an ROV system is mobilised it is a requirement that the ROV control has DP status lights. This is achieved by installing a portable set of lights that are connected to the vessel’s DP system by a cable.
- The same cable had been in use for several years whenever an ROV system was mobilised.
- Inspection procedures have been modified to include portable wiring and a bend preventer/limiter used for future connections.
Considerations
- Connection of ANY temporary system to a DP system should be as part of a formal management of change and properly risk assessed.
- The connection of ANY temporary system should be designed to tolerate a short circuit or any other failure.
- Additional systems that are connected to a DP system should be approved by manufacturer and class and should be extensively tested.
- The vessel is recorded as operating within DP equipment class 2, however only satellite derived position reference systems were recorded as being in use.
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The case studies and observations above have been compiled from information received by IMCA. All vessel, client, and operational data has been removed from the narrative to ensure anonymity. Case studies are not intended as guidance on the safe conduct of operations, but rather to assist vessel managers, DP operators, and technical crew.
IMCA makes every effort to ensure both the accuracy and reliability of the information, but it is not liable for any guidance and/or recommendation and/or statement herein contained.
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