Two incidents with electrical installations with potential for a fire

A member reported two incidents involving failure of electrical equipment, leading to, or potentially leading to, fire hazards.

Incident 1: Earth fault and potential fire hazard

What happened?

Whilst fault-finding an earth fault on the 240v mains system on a vessel, the engineers came across a pair of mains sockets installed above the galley fridge / freezer space.  This space was not ventilated.  These mains sockets were discovered to be heavily soiled by the fat residue that had drifted into this space from cooking in the galley. 

What were the causes?

The fat residue was the immediate cause of the earth fault.  This was clearly a potential fire hazard caused by the fat dripping down into the mains sockets. Causal factors identified were:

• Design flaws in the fitting of mains sockets in such a location;
• Ineffective extraction of fat fumes from the galley;
• Failure to clean the area around the mains sockets;
• Unclear / Inadequate instructions for galley maintenance.

Actions taken? Lessons learned?

• The entire area was cleaned comprehensively once the sockets were isolated and locked/tagged out;
• The sockets were inspected and replaced if necessary, and testing conducted;
• Checks to be made of difficult to access areas, high up areas and such in galleys to ensure nothing similar could occur elsewhere.

Members may wish to refer to 

• Galley electric shock – uncontrolled portable electrical equipment
• Near miss: burnt out electrical socket
• Near miss: potential fire – overheating of oil in deep frying pan

Incident 2:  Minor Electrical Fire in the Engine Room

 A fire alarm was activated from within the machinery space, and on  investigation, a minor fire was noted on the deckhead at the port side exhaust fan junction box.  Given the limited size of the fire, it was tackled with a dry chemical powder extinguisher.  

What were the causes?

Heating was caused by a breakdown in continuity in a terminal block inside a plastic junction box mounted on the machinery space deck head.  The cable possibly suffered breakdown at the termination, or the connection in the terminal block joining the supply to the consumer had weakened, leading to reduced continuity (increased resistance) and consequent heating of the wires.

Actions

• Check physical and electrical condition of connections for high load or continuously running equipment;
• All terminations to be checked as a matter of routine during forth planned maintenance.

 Members may wish to refer to 

• Fire in engine space on crew transfer vessel (CTV)
• Fire in wheelhouse on offshore renewables crew transfer vessel
• Near-miss: burnt out electrical socket

For more information, please contact @legacy.imca-int.com.