Fire in diesel generator following tests
- Safety Flash
- Published on 24 July 2023
- Generated on 19 November 2025
- IMCA SF 18/23
- 2 minute read
There was a small fire in the engine room on a vessel in port.
What happened?
The incident occurred when a diesel generator was being maintained by a third-party maintenance team.
On completion of a change of alternator bearings, the generator was tested at idling speed, and no problem was found. But when the generator was tested at operational speed, after a few minutes fire came out of the non-drive end exciters.
The alarm was raised; the diesel generator was brought to an emergency stop and the fire was put out with an extinguisher.
What went wrong?
- There was a misalignment of the internal cover of the non-drive end bearing.
- This misalignment caused friction against the shaft and subsequent sparking.
- The root cause was considered to be insufficient supervision of the third-party personnel conducting the maintenance.
Lessons learnt
- Whilst there was only a burnt alternator in this case, the potential was for the fire to have spread throughout the engine room.
- Ensure full and thorough supervision of the personnel of third-party contractors.
- Check carefully the status and readiness of any equipment after maintenance and test – in this case, it was as well that they tested it at operational speed rather than only when idling.
Related Safety Flashes
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IMCA SF 12/23
16 May 2023
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IMCA SF 03/23
18 January 2023
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IMCA SF 03/22
28 January 2022
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IMCA SF 25/19
28 October 2019
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