Fire-Fire!!

[HopCar]

It’s bad when your alarm system tries to kill you.
I had an oil pressure switch fail on an airplane engine. It allowed all the oil to pump out of the engine. Luckily it happened on the ground instead of ten minutes later at a thousand feet over the ocean.

 

[Ex Sailor]

Totally with Ski on this one ....
There is not enough load on this circuit to make it burn. Something else ( a larger load ) found the path to ground via this circuit .....
My .02 CAD .... FB

 

[jjorgenson3]

Praise the wisdom of the Guru's.

 

[Art]

Totally with Ski on this one ....
There is not enough load on this circuit to make it burn. Something else ( a larger load ) found the path to ground via this circuit .....
My .02 CAD .... FB

And, the beat goes on!

Good luck in locating load transfer!

 

[Sharpseadog]

Economical Fire Detection System

Started up my Diesel for my weekly check last night and saw smoke coming out of the engine room within 30 seconds. A quick look revealed a small fire (looked huge but was only the size of a Brillo pad)) in the wiring hardness next to the oil pressure sending unit. Since I have 6 fire extinguishers on a 37' boat one was within easy reach. One short blast and the fire was out.

Cause of the fire was the oil sending unit went to ground as soon as the switch was made. The hot side wire of the osu completely melted and luckily no other wires in the harness were damaged.

Lessons from this? Always-always keep a clean engine room. This could have turned out to be much worse.

My best friend lost his Westport 52 (and nearly his 8th of his 9 lives) because he was alone on fly bridge and didn't discover engine room fire in time. He spent 45 minutes in 48 Degree water before he was rescued. You can see the rescue on U-Tube:

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I have a cheap and effective recommendation to make sure you know about an engine room fire in time to put it out with a portable fire extinguisher. Both Kidde and First Alert make wireless smoke detectors that can be wirelessly linked. These are about $20 each. I have one in my engine room, main cabin (as a repeater just in case), and most importantly one on my fly bridge. If the engine room detects even a trace of smoke, they all go off. It's probably a good idea to tow you dinghy too. My friend couldn't launch his due to fire coming up companion way

 

[foggysail]

Found the cause of the fire. It was an old 4 pin relay that had the coil fail or short. This relay is used to sound an alarm should I get a hi tranny temp, a high engine block temp or low oil pressure. These 3 alarm points provide the ground to the relay which in turn energizes an audible alarm. When the coil shorted it sent 12v down to these switches (alarm points) and grounded out. There wasn't a fuse in this 1969 vintage wiring but there is now . I am really lucky in that the only damage was 12" of melted wire.

The usual cause for fire is not shorted wiring but rather poor electrical connections. And if you do experience a true short where the circuit is not protected for overloads, it usually will take out the entire wiring harness especially if the wires are PVC and not teflon.