So today I thought I would wire in one of the Yakbitz Yakker NMEA to wifi devices to view the AIS data from my VHF radio on the Navionics app on my phone.

I recently rewired most of my boat. I would say I did a thorough job of this, consulting with an electrician/boating colleague and doing the bulk of the wiring at home. The installation was smooth and only took an afternoon which was a surprise.

I had noticed that since I did such a good job of the wiring any additions or alternations I have made since I had taken a somewhat more relaxed approach.

Anyway today I thought I would wire in this device and stupidly decided to do a quick job, with no fuse, so I could test it out. I was then going to do it properly if it all worked. Any way it did all work brilliantly. But taking this shortcut was a mistake.

Just before I was about to pull it apart and wire it in properly the 12v wiring just lit up and caught on fire. It was like a bomb fuse from the movies burning from one end to the other. Smoke was filling the cabin. I thought the boat was going to burn down. In an instant I grabbed the wire and tried to pull it out of whatever it was connected to. This was a mistake. Then I turned off the power and everything settled down slowly.

Grabbing the wire was a mistake. It burnt my thumb and fingers which have now blistered up. The burning wire also damaged several other wires which I had to replace or shorten.

After calming down and venting out the cabin I installed the Yakker properly, with a 1 amp inline fuse this time. Surprisingly the device worked fine.

Next time I will always use a fuse no matter what I am doing.... and never take shortcuts.

I also dont think my boat has an inline fuse on the battery switch so I will soon be upgrading this part of the wiring on my boat.

Great post there. Yes fuse out of the battery +ve is the first component to fit.

These are good references - obviously don't read them all.............select the one to suit your needs.

www.boats.com/on-the-water/12-volt-basics-for-boaters/

www.amazon.com/dp/0071392335/ref=cm_sw_su_dp

www.smer.fi/docut/12volthandbook.pdf

www.whitsundaydiscountmarine.com.au/assets/files/DIY%20Boating%20Magazine/Electrical/Marine%20Electrical%20Systems.pdf

I blew up fuses recently with obviously dodgy assumptions ..............this site has great resources as regards circuit diagrams.

newwiremarine.com/how-to/wiring-a-boat/

This article refences the ABYC elec standards which are an excellent guide.

stingysailor.com/2018/12/08/complete-rewiring-2/

Hi JB,
That's very Interesting. One would assume that you had a lot of current flowing to get the wiring to catch fire and the simple addition of a fuse adds minimal resistance.
The addition of a 1 amp fuse that didn't blow means there is nowhere near enough current to melt normal (say 24awg) wiring.
Why the hell did it catch fire first, then not blow the fuse?
No short somewhere?

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shaggybaxter said..
Hi JB,
That's very Interesting. One would assume that you had a lot of current flowing to get the wiring to catch fire and the simple addition of a fuse adds minimal resistance.
The addition of a 1 amp fuse that didn't blow means there is nowhere near enough current to melt normal (say 24awg) wiring.
Why the hell did it catch fire first, then not blow the fuse?
No short somewhere?

Hi shaggy

sorry my post wasn't clear. There was no fuse when it caught fire. That was my mistake. I was taking a short cut. I can only assume the positive and negative wired some how came in contact with each other. The Yakbitz Device is pretty dodgy and flimsy. The positive and negative are right beside each other which I suppose isn't a problem if you have a fuse
I added the 1a fuse when I re-wired it again.

Thanks JB, that make sense. Well done for saving the the widgets with the flashing lights either end, wiring is much more tolerable to replace than the expensive bits that are connected to it.

Fuses are put in place to protect your wiring, not the items on the end of it.

If the item on the end of it has a fault and shorts itself and draws more current than it should, it may burn itself out but a fuse will prevent the damage going any further.

JB, considering your cabin filled with smoke and fumes, I advise you check all your wiring for melted insulation which may cause further shorts.

Upon reading Nigel Calders boatowners manual I put in more fuses. I did not have any in my motor cables which was stupid. He says it is even important to work out where to put them, close the the battery means you can't have the leads short where they may be chafed and short circuit before a fuse on a switchboard or nearer the motor. Maybe a fuse (or better yet a breaker) before each bus bar, rated to the max of the appliances there.

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cisco said..
Fuses are put in place to protect your wiring, not the items on the end of it.

If the item on the end of it has a fault and shorts itself and draws more current than it should, it may burn itself out but a fuse will prevent the damage going any further.

JB, considering your cabin filled with smoke and fumes, I advise you check all your wiring for melted insulation which may cause further shorts.

hi Cisco. Yes the burning wire cut through the insulation of a few wires like a hit knife through butter. I had to cut the ends off those, crimp on new terminals and reinstate them.
yeh a fuse is to protect the wire. I have now seen it in practise. I am still surprised though that the yakker survived.

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Kankama said..
Upon reading Nigel Calders boatowners manual I put in more fuses. I did not have any in my motor cables which was stupid. He says it is even important to work out where to put them, close the the battery means you can't have the leads short where they may be chafed and short circuit before a fuse on a switchboard or nearer the motor. Maybe a fuse (or better yet a breaker) before each bus bar, rated to the max of the appliances there.

Hi Kankama. Yeh I have always looked at putting the blue sea terminal fuse blocks on my battery terminals to protect the motor cables. What amperage did you use? I understand it should be sized to protect the wire but they are of such a high gauge I would think selecting the lowest possible amp rating would be wise but it would also need to be high enough t not blow when the engine is started.
also do people use a fuse on the voltmeter? Most wiring diagrams don't have a fuse here but it's wires should also be protected.
I have lent my Nigel Calder book to a friend. I do have another dc wiring for boats book but it doesn't cover this.

my experience has made me question the rest of the wiring in the boat.

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Kankama said..
Upon reading Nigel Calders boatowners manual I put in more fuses. I did not have any in my motor cables which was stupid. He says it is even important to work out where to put them, close the the battery means you can't have the leads short where they may be chafed and short circuit before a fuse on a switchboard or nearer the motor. Maybe a fuse (or better yet a breaker) before each bus bar, rated to the max of the appliances there.

Hi Kankama. Yeh I have always looked at putting the blue sea terminal fuse blocks on my battery terminals to protect the motor cables. What amperage did you use? I understand it should be sized to protect the wire but they are of such a high gauge I would think selecting the lowest possible amp rating would be wise but it would also need to be high enough t not blow when the engine is started.
also do people use a fuse on the voltmeter? Most wiring diagrams don't have a fuse here but it's wires should also be protected.
I have lent my Nigel Calder book to a friend. I do have another dc wiring for boats book but it doesn't cover this.

my experience has made me question the rest of the wiring in the boat.

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Kankama said..
Maybe a fuse (or better yet a breaker) before each bus bar, rated to the max of the appliances there.

Good point Kankama. Circuit breakers on all the high current circuits (hard to get an 80amp fuse) and for all mission critical components like autohelm, comms and power for the bus backbone for boat sensors. Fuses for everything else.
Losing power to something always seems to happen right at the most inconvenient time, like entering unfamiliar confined waterways at night in teeming rain .

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jbarnes85 said..
I can only assume the positive and negative wired some how came in contact with each other. The Yakbitz Device is pretty dodgy and flimsy. The positive and negative are right beside each other which I suppose isn't a problem if you have a fuse
I added the 1a fuse when I re-wired it again.

Hi JB, Thanks for posting, we all take short cuts and usually get away with them. Good to hear you didn't fry your device but still does not explain what happened so you may still have a problem.

I'm hoping you took some photos before you cleaned up your burnt wiring. To have catastrophic insulation burning like you describe it must been a prolonged short to ground. If you just touched the device +ve to a grounded part of the boat it would be momentary, you would get some melting and flame but as soon as you moved the device the short circuit would be broken and no continued action.
If you twisted the device and caused the +ve and -ve leads to touch and stay touching you have a short to ground and I would expect as the wires heat up BOTH wires would start to burn - this seems most likely but if your -ve wire didn't also burn I would be looking for some other reason.

Putting a fuse in doesn't explain why this happened, it just limits the damage if it happens again. so, temp hook up, exposed wires entering a device, touch and cause a short or ???

Final question, where did you get the wire and how was the insulation rated?

these guys are pretty good.
I purchased flexible solar panels, switchgear, cables etc from them, good service, decent products and advice:

www.solar4rvs.com.au/circuit-breakers/fuses/

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DrogueOne said..

jbarnes85 said..
I can only assume the positive and negative wired some how came in contact with each other. The Yakbitz Device is pretty dodgy and flimsy. The positive and negative are right beside each other which I suppose isn't a problem if you have a fuse
I added the 1a fuse when I re-wired it again.

Hi JB, Thanks for posting, we all take short cuts and usually get away with them. Good to hear you didn't fry your device but still does not explain what happened so you may still have a problem.

I'm hoping you took some photos before you cleaned up your burnt wiring. To have catastrophic insulation burning like you describe it must been a prolonged short to ground. If you just touched the device +ve to a grounded part of the boat it would be momentary, you would get some melting and flame but as soon as you moved the device the short circuit would be broken and no continued action.
If you twisted the device and caused the +ve and -ve leads to touch and stay touching you have a short to ground and I would expect as the wires heat up BOTH wires would start to burn - this seems most likely but if your -ve wire didn't also burn I would be looking for some other reason.

Putting a fuse in doesn't explain why this happened, it just limits the damage if it happens again. so, temp hook up, exposed wires entering a device, touch and cause a short or ???

Final question, where did you get the wire and how was the insulation rated?

Hi

both wires did burn and they burnt from the device back. I suspect you are spot on about twisting the device and the positive and negative coming in contact as I had just moved the location of the device and likely twisted everything.
the wire was dual core marine wire from jaycar rated to 7.5 amps only. Not sure why I have it. Maybe for some trickle charger 10w panels. Replaced it with a more appropriate higher grade wire.

unfortunately no photos.

I used a high amp circuit breaker like the type needed for an electric anchor winch on my motor cables. It seems to work well. It makes me worried in retrospect as I didn't have one for about 17 years in the motor circuit - lucky I guess.

www.altronics.com.au/p/s5885-50a-surface-mount-ip67-waterproof-circuit-breaker/?gclid=CjwKCAiArbv_BRA8EiwAYGs23KNSPBJ7MY5ERw-jGuL7k_0lCywT3KXnVD6gJFX76i2uFeM2D-FYoxoCnVEQAvD_BwE

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Kankama said..
I used a high amp circuit breaker like the type needed for an electric anchor winch on my motor cables. It seems to work well. It makes me worried in retrospect as I didn't have one for about 17 years in the motor circuit - lucky I guess.

www.altronics.com.au/p/s5885-50a-surface-mount-ip67-waterproof-circuit-breaker/?gclid=CjwKCAiArbv_BRA8EiwAYGs23KNSPBJ7MY5ERw-jGuL7k_0lCywT3KXnVD6gJFX76i2uFeM2D-FYoxoCnVEQAvD_BwE

Excellent move Kankama.

Everyone should have a circuit breaker like this - in fact, it should be mandatory for all boats.

jbarnes85 - one of these would have protected your wiring and saved you from potentially losing your boat.

I can't over emphasise the importance of circuit breakers in marine electrical systems

regards to all,
Allan

When the lightning hit my boat most of the cabin LEDs were blown but not all, and the mast LED lights blew up, wind wane gone, vhf areal gone, wire burned, both of the chartplotters cooked but only one of the fuses on the chartplotters.
The 200w solar panel shatrered, blew up like a bomb but the in line fuse was fine, so was the mppt controller.
Batteries all good, fuses intact.
On the switch board all fuses gone, circuit brakers ok.
All the other radios cooked and most other fuses blown but not all of them!

How's that possible, I don't know, let the electricians solve the conundrum but when I rebuilt the boat - bless the QBE mob - I fused every single electrical item, for sure.

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Kankama said..
I used a high amp circuit breaker like the type needed for an electric anchor winch on my motor cables. It seems to work well. It makes me worried in retrospect as I didn't have one for about 17 years in the motor circuit - lucky I guess.

www.altronics.com.au/p/s5885-50a-surface-mount-ip67-waterproof-circuit-breaker/?gclid=CjwKCAiArbv_BRA8EiwAYGs23KNSPBJ7MY5ERw-jGuL7k_0lCywT3KXnVD6gJFX76i2uFeM2D-FYoxoCnVEQAvD_BwE

Hi Kankama - doesn't the 50amp breaker trip when you start the engine? And do you have two - one on the starter battery and one on the house battery?
I was planning to use the BlueSea battery terminal fuses and was doing some research and some resources recommended a fuse of 250amp. I was then planning to put another 30amp fuse before my dc bus bar (it's enough for my small amount of electronics). Hence my question.

I have a 25 hp outboard and the breaker may be a 50 or 80 amper - I can't remember. The motor doesn't need much current compared to a diesel.