Craig & Katherine Briggs SN 68 Sangaris Tropic Isle Harbor, FL <sv_sangaris@...>
Bill's comment that these problems can be elusive and your saying it is a straight run in a conduit reminded me of a problem in SM Miss Lindy years ago. They had had near-fire meltdowns of all the major wires in the engine room (looked like Dali's clocks dripping). Three times over just a few months!
Each time they had "professional marine electricians" replace all the damaged wires. After rewire #3 in Cartagena, we happened to be leaving the same day and they had meltdown #4. We got them to anchor near us in the San Blas and I spent 3 days cobbling their system back together. I finished, but noticed a slight potential between the start negative and the engine block. Scratching my head and thinking I was wasting my time, I disconnected the battery wires and pulled them out of the conduit a few feet. Sure enough, there was a slight chafe-through in the insulation that under the right conditions underway would allow a dead short.
Obviously just a shot in the dark and unlikely to be the cause, but maybe worth pulling and inspecting the wires in the conduit.
Good luck with it,