Electrical Fire/Damage

B

Bob Ware

Well-known member
Member
Joined
Jan 1, 2000
RO Number
513
Messages
234
Some background. Saturday afternoon after having been anchored for a couple hours, when I cranked up the starboard engine (Yanmar diesels) started billowing smoke. Got the fire extinguisher and lifter the engine hatch to find a section of wiring burning/melting. Sprayed it to cut down the smoke then turned off the battery which stopped further damage.
The short/burning happened in a section of the wiring harness with numerous wires bundled.

Question for the crew. Would you be inclined to simply order a complete wiring harness or attempt to replace/repair damaged wires? My thought is to replace the entire wiring harness as trying to track down the cause and replace each damaged wire will be inviting further problems down the road.

I've never experienced electrical issues of this magnitude so would appreciate your thoughts here.
 
Get the harness if you can as it will have all connectors etc
Inspect the old one for the root cause
 
Replacing the whole harness won’t tell you what the cause is.... it will just cause you a new harness
 
I trust everyone stayed safe, Bob. Fire and flooding - two of the worst words in boating. . ..
 
Thanks Gene, yes, thankfully it turned out to be minor so everyone is safe.

Pascal, while I understand your comment I don't quite know how I could determine a cause at this point. The section of the bundle is completely destroyed. After hitting it with the extinguisher I could see the wires glowing red until I switched off the battery. I will say, however, I haven't made it to the marina to closely examine things so there is possibly some evidence.
 
The last time something like this happened to me, it turned out to be a bad ground wire. Be sure you grounds are all clean and secure.
 
Look at the surrounding area for any indicating that something was rubbing and shorting the wires. They will melt between the power source and the burn spot not much further along unless the short was at the very end of the wire. In that case loot at whatever they connect to. Check resistance of that with a meter.
No fuse on the system?
 
Well, I spent time today cleaning up the mess and looking over the damage. I think I found the culprit to be a spot where the wiring harness has been rubbing against the edge of the metal cover of the turbo air intake filter/breather. There is a spot on the cover which shows burn marks/paint melted and some of the wires are burned through in that area. Additionally, insulation on several other wires was completely melted away with others showing signs of melting/overheating. Definitely a full harness replacement.
I can't imagine how long it's been rubbing like that but I haven't touched the turbo cover or that harness for many years. Thankfully, it happened when and where it did as we were just about to lift anchor and join in a 200+ Trump boat parade through what would have been a crowded channel.
Appreciate your suggestions.
 
Bob, sounds like you have a plan. It could have been much worse. Fire scares the you no what out of me. Good luck with the repair.
 
The question is why didn’t a breaker trip. Pretty much every wire and harness should be protected by a CB except the main starter wire. A short in the harness on an engine should have tripped a breaker.

If twin, check the other engine... /)
 
You're right, of course, Pascal so I'll need investigate the breaker question. What I've found over the years is this Luhrs has what I would call some shortcomings in some areas and I suspect this is one which I had not discovered yet.

I checked the other engine Tuesday after discovering the cause of the problem. Thanks for the reminder.
 
Mice have been known to chew wiring. But from what you mention I would say chafe.
 
What type of fire extinguisher did you discharge into the machinery space? Was the engine running at the time of discharge?
 
quote:
Originally posted by L. Keith

What type of fire extinguisher did you discharge into the machinery space? Was the engine running at the time of discharge?

Click to expand...


I was wondering the same - probably for the same reason, I’d bet. But if I was betting anyways, I’d guess if it was a handheld and not one of the newer FE241 fixed systems, it was a plain old powder bomb ABC. Rare to see CO2 or PKP on a recreational boat. Or on old Halon fixed system with the potential for fun things through a Diesel engine.

OP: If you have the kind of lock that graces you with another electrical fire, cut the power FIRST, then assess your residuals. Likely just a mild class A burn and residual smoke at that point. Save yourself lots of cleanup and exposure, not to mention being by far the more effective approach to an electrical fire.
 
To answer your questions. Mike, you are correct, just the plain powder bomb extinguisher so some mess to clean up. The boat does have an old Halon auto system installed but no longer operational. I had stopped both engines prior to raising the engine hatch. Although cutting the power first would have been ideal, as well as resolving the problem, the battery switch is immediately astern of where the fire was located so I wasn't going to risk crawling down in there to reach the switch. So I did have some needless cleanup but not too bad.
 
Bob- That's great you stopped the engines prior to powder bombing. As you know, that likely saved your engine(s) or at least greater expense. In a fire emergency the proper sequence of response steps can get a skosh blurred.

Sorry you had that traumatic experience and hope you get the wiring squared away before long .
 
You must log in or register to reply here.
Back
Top