Mariner 2897 Wire chaffing

[Struggler]

I just got my hands on this boat - 1985 Mariner 2897. I discovered wire chaffing on the main 110v wire from the inlet to the bus, among other wires (12v) near the port side transmission. The boat has not had power on it in two years, the previous owner didn’t recall any electrical issues. I’m curious why this happened? Overload? The previous owner had tons of things plugged in throughout the boat.

Any ideas on why this occurred? Can you identify which wire is the culprit? Can the 12v wires be spliced and new sections put in with butt joints?

Thanks!

[bud37]

Welcome to the forum.....kinda looks like the 12vdc wires have overheated ( perhaps a high current draw, or short ).....do you know what those wires power up ??

[Midnightsun]

I agree, looks like a 12v power line got too hot and caused the meltdown which touched the exterior of the other wires although we really cannot see to well on just a picture. Look for the wire showing the most and longest run of bare scorched wire as this would be the one that caused it all. Trace it down and see what was connected to it. Probably way too many items and not properly fused.

This is what happens when one connects stuff to lines without knowing the basics of power delivery/gauge amp capacity of electrical wires! I would try to entirely replace the wire that shows internal heat damage or the cause if you prefer. Those that were beside the hot wire and show scorching on the outside with no visible penetration to the actual wire itself could be easily protected by adding insulation around the externally damaged area. Just a fancy way of saying add high quality electrical tape, not the dollar store variety, big difference!.

[Struggler]

Thank you and I agree and will replace the badly chaffed wires. Onboard fire is the only thing that’s worrisome.

[Midnightsun]

On another note while you are into electrical. Your boat is an 85 so basically antique by car standards. Nothing wrong with this at all as many out there are still in great shape and perform wonderfully. After 35 years of shore power connections it would be wise to unscrew the main electrical inlet and check the wiring connection as these tend to be troublesome with time. If there is enough slack in the cable, detach the wires from the outlet, cut back an inch or 2, skin it appropriately and reconnect. This will give you a fresh good contact for the main power supply of your boat that will last for at least a decade or 2.

A reminder to all to check those shore power cord connections at both ends for any signs of plug/prong scorching even minimal as this is where the vast majority of boat fires start. If there are signs, chuck the cord and get a new one or if you know what you are doing, replace the bad end plug/s.

[Struggler]

I’m going to replace the entire line from the inlet connection to the main panel based on it being exposed to an abnormal amount of heat in the pics above. I will check the plug that it’s attached to and replace that if needed also. Thanks for that advice!

[tomschauer]

The first pic looks like something hot was laid on those wires and melted the insulation. the way it is melted looks external, and doesn't look internal (over current) to the wiring. Maybe a quartz trouble light or some type of heater was used and allowed to lay on that wire bundle.

[Viper]

Hard to tell but it looks like over-current to me. Looks like the yellow/black pair and brown/black pair were next to each other and the white cable up against them. The brown wire is typically used on pumps so see if it leads to a bilge pump, it might be seized and could have caused the meltdown if a breaker didn't trip. The yellow wire, besides being used for ground in some newer applications, could be anything. Check your blowers, trim tabs, and neutral safety on the transmission but that usually has a red tracer in a lot of applications if I recall.

Let us know what you find.