Warning and SAFETY REMINDER !!!!!

[Maine Sail]

Hi All,

So here we are victorious in our "first to finish", with a solid 5 boat lead mood, when all of a sudden a call from bellow of smoke?

We had no sooner crossed between the committee boat and the mark, and fired up the iron genny,when one of the crew says in a rather nonchalant manner "hey there is some smoke down here?" Well the skipper and I immediately kill the engine and pop the genny back out while calling for a shut down of the battery selector switch. Within seconds the smell of an electrical fire is filling the cockpit and the cabin looks like a Cheech & Chong movie only it doesn't smell quite as good..

I grab the helm and the owner goes bellow and begins digging into things. About 20 minuted later he pops his head up with a 24" long piece of bare 14 ga SOLID copper wire. I chuckle and say "see solid wire has no place on a boat!!".. Unfortunately I had no idea how wrong I was! That 14ga SOLID copper wire had been 14ga tinned multi stranded wire with a jacket just minutes before!!

Never in my 35 years of sailing have I seen a two foot long piece of multi-stranded wire turned into a piece of unjacketed solid copper so fast!!

Now I know the "alarmist crowd" will be out in full force on this thread but let me assure you this boat (it's the "red boat" for those in the know) is kept in pristine mechanical and physical condition This is not a boat that is left to chance on ANYTHING and the owner spares no expenses keeping her up!!

So here's the safety reminder!!!!!!

FUSE YOUR BATTERIES AS CLOSELY AS YOU CAN TO THE BATTERY POST!!!!!!!!

So here's what we found. The ground lead for the metal cigarette lighter and female quick connect that looks like this picture came disconnected!

When it did it began swinging into the stud for the house bank on the back of the battery selector switch! OUCH!!!! Who said there is NO vibration on boats? I'm sure the "no vibration on boats" crowd will be commenting at some point.. Remember this wire went straight to the ground buss and was rubbing the battery selector switch terminal post a direct ground short of the worst type!

Eventually it hit hard enough, possibly aided by the vibration caused from starting the engine, to literally weld itself to the stud and then turn the wire to a solid conductor! I'm not kidding when I say that I could not decipher this wire from a piece of Romex used in house wiring. There was no physical sign of any stranding left anywhere and no sign of any tinning either. this wire got so hot there was not even any residue left from the melted jacket just BARE copper..!

Luckily this was only a 14ga wire and it actually blew like a fuse after it thankfully got hot enough. A fuse at the battery post such as a ANL type like the one bellow would have stopped this ground short in about a nano second!!:

Unfortunately, this fuse block is one of those items the owner had been "GOING to add" but as boats go it kept getting further and further down the "to do list" as other chores and projects piled up... We all are guilty of this type of mistake!! "Oh I'll get the flares on the NEXT trip to West Marine..."

So what have I learned?:

#1 Be very, very, very careful using "quick connect" terminals on boats! If you MUST use them use the fully insulated style and NOT the un-insulated ones!!! EVEN ON GROUND WIRES!!! They look like this:


#2 You should make every effort protect the studs on the backs of battery switches or ANY other large amp cable terminals with post caps!!

#3 Any wire in the vicinity of HOT terminals needs to be secured so there is NO WAY, even if it came disconnected, to touch a HOT component. Zip ties are CHEAP!! This wire was zip tied within 6" of the cigarette lighter but it was still not enough to prevent it from falling onto the battery post!!!

#4 And finally the MOST important component is that ALL battery banks MUST have a fuse as close to the battery as possible!! ABYC suggests 7" but I know mine are about 9" to 10" as it is the closest I could get them..



DO NOT wait, as my buddy did, to fuse your batteries!! If this has been on your list please, for your own sake, MOVE IT TO THE TOP!!!!!

BTW the post this wire came in contact with was the direct to the battery and even turning off the switch DID NOTHING. The only way we prevented a fire was because the wire melted in half and acted as a fuse because it was a light 14 gauge run . If this had been a 10 ga wire, for say the macerator, we may have burned the boat to the water line last night..!!!

Think about it!!!!!


Call me an alarmist but if you witnessed what I saw last night you'd have been buying fuse blocks TODAY!!!

This is an easy install:

[jrd22]

Thanks for the important info. Halekai. I am not familiar with the type of fuse block you show, do you run a short battery cable from the positve post of each bank to a fuse and then your batt. cable? What amp rating fuses are required, seems like they would have to be pretty high to not blow when using the windlass.

I'll be installing them as soon as possible.

Thanks again, John

[sailingdog]

thanks for the heads up halekai

[Maine Sail]

Originally Posted by jrd22

Thanks for the important info. Halekai. I am not familiar with the type of fuse block you show, do you run a short battery cable from the positve post of each bank to a fuse and then your batt. cable? What amp rating fuses are required, seems like they would have to be pretty high to not blow when using the windlass.

I'll be installing them as soon as possible.

Thanks again, John

Yes you either make your own jumper or buy one. I run 200 amp ANL fuses in mine as my starter uses about 160 max amps and I want a little blanket room. They go up to 300 amps which is plenty for most windlasses.

There should be NOTHING between the fuse and the battery post but battery wire. Everything will connect down stream of the fuse..

This is the exact ANL fuse block I use Blue Sea 5005 I purchased them from Hamilton Marine for about $20.00 and the fuses run about $15.00 a pop.. Keep in mind for jumpers that the fuse block has 1/4 X 20 studs and your battery most likely has 3/8" studs so you'll have different lugs on each end of the jumper and may need to re-lug your battery cable end to 1/4".. You can always source a higher amp fuse block with 3/8" studs too Blue Seas makes them to 750 amp the 5005 will do 300 amps..

[TxLnghrn]

Thank's Halekai,
Another great post as usual, I'm glad nobody got hurt. I'm not sure I completely understand what you wrote (I have a learning disability when it comes to electrical) but I have printed it out and will be refering to it as I learn about and rework my electrical system as this months project.
Michael

[Rockter]

Big batteries are notorious for generating fantastic currents, and quickly.

Would the fuse have tripped it though? If the wire is fine, the temperatures will be fierce before the fuse trips, if it trips.

Certainly fit one, but beware.

[Maine Sail]

Originally Posted by Rockter

Big batteries are notorious for generating fantastic currents, and quickly.

Would the fuse have tripped it though? If the wire is fine, the temperatures will be fierce before the fuse trips, if it trips.

Certainly fit one, but beware.

I've blown my 200 amp fuse before... It actually blows quite quickly when there's a direct short.

Being very comfortable with electrical work can be a bad thing as I often work on both my boat and home panels live. I know dumb, but comfortable with it. Occasionally a screw driver shorts across something.. It always sucks to pop a $15.00 fuse but they do blow with a dead short..

[lbdavis]

That wasn't the only "smoking" going on. You guys smoked the field, too. I was motoring in on the SP side of you all on your downwind leg. You were putting a boat's length in every minute it seemed. That boat flies in light air!!

[SteveInMD]

It sounds like you guys did exactly the right thing by quickly shutting down the engine and batteries. Sometimes people go straight to the fire fighting mode and forget about shutting down the batteries. It's really amazing how much smoke a small about of wire insulation cranks out. I'm glad to hear no one was hurt.

[chucklesR]

Sometimes those accessory items (12 v adapters, fans etc..) come with the quick connects. I paint them with liquid tape to make sure they can't come loose by vibration or even the tugging and moving that happens when you wire in the next 'thing' you just have to have.
I've spent hours pulling wires and tracing runs on my boat to fix two loose connections from the factory now, each time I paint the connections with liquid tape so I'll always know if something is moving or touching other things.

Those times when you must connect something directly to the battery (bilge pumps comes to mind) you must fuse them with an inline fuse of correct size for the wire - in a perfect world you'd never have anything directly connected to the battery except the switch (I don't because I have no bilge pumps - still).