Electrical short

[Ixneigh]

Hi. The fuse for the cabin light circuit keeps blowing. Like as soon as I replace the fuse and switch it on. No other circuits are affected. No changes have been made. Light circuit was left on but lights turned off. Nothing left on, but circuit energized. When I returned to the boat after a dinghy outing, the fault was noticed.
No visible damage to yacht, no burned wiring no lightning strike this afternoon. Running lights work. Accessory switch works. Are there any know issues? Currently running off emergency Pomlight lanterns. Thank you.

Ix

[kmclemore]

I would drop the two interior lights, disconnect them. Next, check the source wires for shorts and then for proper power supply. Finally, check each of the lamp units for shorts. That procedure will almost surely find the source.

[Ixneigh]

This morning I recalled my dad mentioning that sometimes the switch goes bad if it’s worn, and can heat up and cause a short. I swapped out the cabin light switch for one of the others which are hardly ever used. That seemed to solve the issue. I’ll pick up a replacement switch at the auto parts store where I believe I’ve seen them before. Also some more fuses since, while I was sure I had plenty of them, I can’t locate them now.
Last night I did check the light fixtures as I thought one may have filled with water from an unnoticed leak. But all the fixtures were fine.
The switch board, of course, appears to be of marginal quality, although it lasted a good while. I intend to put a 20 amp fuse on the dc supply side of the panel while I have it open.

Ix

[Be Free]

I've never looked at the wiring on an "M" but assuming it is the same as an "X" your all of the cabin wiring would have come from the factory with 16 AWG lamp cord. That cord is only rated for 13A so putting a 20A fuse on it may not be the best idea.

[Ixneigh]

Actually the boat is equipped with marine duplex wire. I think I heard something many years ago about that being the case with the M model.

Ix

[tuxonpup]

My '96 has marine wire running fore and aft and virtually no other upgrades, I'd be surprised if it was the PO who did it.
I added a 15A fuse at the battery end of the run to the light panel. With inline fuses, I usually electrical tape a spare to the wire running to the load it's protecting, as my eye sight will most likely not be of much help reading the engraving on the blown one.

[Be Free]

Actually the boat is equipped with marine duplex wire. I think I heard something many years ago about that being the case with the M model.

Ix

That's a pleasant surprise. You need at least 12 AWG to carry 20A safely in any case.

[Be Free]

My '96 has marine wire running fore and aft and virtually no other upgrades, I'd be surprised if it was the PO who did it.
I added a 15A fuse at the battery end of the run to the light panel. With inline fuses, I usually electrical tape a spare to the wire running to the load it's protecting, as my eye sight will most likely not be of much help reading the engraving on the blown one.

Unless the factory went backwards in wiring standards between '96 and '01 your boat was likely rewired by a PO.

The factory wiring was bow light, stern light, steaming light (on mast) and two interior lights. Do you have something different?

[tuxonpup]

My '96 has marine wire running fore and aft and virtually no other upgrades, I'd be surprised if it was the PO who did it.
I added a 15A fuse at the battery end of the run to the light panel. With inline fuses, I usually electrical tape a spare to the wire running to the load it's protecting, as my eye sight will most likely not be of much help reading the engraving on the blown one.

Unless the factory went backwards in wiring standards between '96 and '01 your boat was likely rewired by a PO.

The factory wiring was bow light, stern light, steaming light (on mast) and two interior lights. Do you have something different?

Bow, stern, steaming and interior as stock. Maybe the dealer upgraded it when installing the original Nissan.

[OverEasy]

Just a suggestion…. When we improved our electrical system on Over Easy we ditched the barrel and plug fuses and went to manual resettable circuit breakers. No more have to play hide and seek figuring out what circuit has an issue or fumbling around trying to recall where the spares are (or were used up) or struggling to remove/replace the errant fuse while bouncing around.

The circuit breakers self indicate and re-energizing the circuit is simply a push reset.

We love the simplicity that the removal of fuses and the adding circuit breakers has provided us!

Best Regards,
Over Easy