Melted bowthruster switch

[stephanfeb]

Hello

A few weeks ago I took my just-purchased boat out for a short shakedown sail.
A day or so later I noticed that the bowthruster switch (Perko 250W) was no longer working and the knob seembed broken.

I purchased a replacement switch and when I went to install the replacement, I got a big surprise (see attached pic). Basically the switch had melted down completely.

I replaced the switch with a new exact model and the windlass (shares a circuit and master switch) is working, but the thruster is still not working (holding the "on" button at controll panel does not activate the panel).

I now have a new control panel on order, hoping that the panel is somehow faulty, but I'm *very* worried about how I could have melted that switch. I've checked all fuses and they are OK.

Any advice is much appreciated
Stephan
SV Andiamo II

[irwin37]

Check for shorts, or possibly a locked rotor. If the bow thruster is frozen it would draw 2-3 time its normal current, you say the fuse was ok, might be to big for the wire, If the wire is marginal in Gage size a locked rotor or long continuous use of the thruster and or windlass could heat the wires, last but not lease were the lugs on the switch tight and are the crimps properly crimped or soldered? Keep a close eye on it,looks nasty.

[smac999]

if it only melted in that one spot then probably those nuts were lose or the switch inside was dirty / bad contacts.

if you were drawing 2-3x more current then should be, the entire wire would melt, not just one spot.