Overhead 15 watt Light Fixture: Heat Damage

Incandescent wire overheated

Overheated Incandescent wires

The light fixture above the chart table has two 15 watt light bulbs, one white and one red and switched for independent operation. This fixture was removed during headliner takedown for access to install deck organizers and rope clutches.

Upon inspection the incoming 12 volt supply wire (separate black and white) was found to be neatly tucked between and touching both the bare bulb and the reflective metal plate. The insulation on both wires at this point was charred, very hard and brittle and bare copper strands were exposed.

Light fixture

Light fixture

The light fixture in the left photo is the same type (single bulb only) and the incoming feed wire is installed in an identical manner. And although the wire insulation is not charred the insulation is hard and breaking up. The right hand photo shows the effect of the many, many hours of use of the chart table white light bulb in contact with these sections of wire. The boat, a CS33, has 6 like fixtures and in all cases the incoming feed wire is captured in the same manner, as this was the installation procedure followed. Only on the much used chart table light as the deteroriation reached a danger point. The correction is easy but must be done. On the chart table light the damaged wire has been cut back (a few inches of extra wire was pulled from behind the headliner) and the connection was moved to the opposite side of the fixture well away from the bulb. The other fixtures only required moving this connection to the free space opposite the bulb.

Check your fixtures and if any wires are in contact with or too close to the bulb the wires are easy to reposition out of harm’s way. This check and repositioning only requires removal of the globe.

By Ed Sulis

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