Faulty 12 volt power point socket Fire put out with a jar of olives in Brine

[kryg]

Originally Posted by witzgall

Fuse at the source would be my first suspect. I think these outlets are rated at a max of 8A at 12v, maybe less. So corrosion (it was in the galley) + high-amp usage (what were you plugging in??) + maybe less then stellar construction + no fuse at the unit?


On our last boat (wauquiez), we had some European two-pin connectors throughout the boat. I made up an adapter to plug in Cig lighter type items. Maybe that is a better way to go, with a Hella plug or something like it?


We have two of these cig lighter plugs on gossamer, I am going to inspect them both tonight, especially the one in the cockpit!


Thanks for sharing,
Chris

Thanks for your comments After a good rain I'm using the 12 volt socket mostly to run a very small 4 amp powered pump to move rain water from my dingy which sits on the foredeck,into my boats 2 x 100 liter water tanks saves me going to the marina using town water.


Re fuse it dawned on me this morning I had made an instillation error. I was thinking only one side of the fuse equation the male plug side requiring the power and not the female socket power delivery as per my photos. Still these plugs are promoted as water proof, but none are fire proof as well. .

[kryg]

Originally Posted by exMaggieDrum

Loose connections can cause a great deal of heat. A loose connection is not a short so may or may not cause a fuse to blow. I would think it would take a fair amount of current to cause damage like this though.

Loose connectors are one of the main causes of fires on boats, but usually on bigger wires, like alternator connections. It does not take a huge spike in current to start a fire, as only a steady current can do the damage.

I would inspect the fuse holder and the fuse on this install to see if the fuse had shorted and was therefore routing current around it or the fuse was too big for the application.

I would also inspect the plugs in use at the time. AND, whenever a male or female plug gets hot the corresponding female or male socket should be inspected as it make be damaged by the heat and/or causing the problem in the first place. Shore power cords/receptacles are a known and serious hazard in this regard. A hot shore power plug that has to be replaced should also cause you to carefully inspect the other side and replace if there is any suspicion at all of damage to it.

You were very fortunate you were onboard at the time and noticed the problem and were able to put it out. Liquids should not be used for electrical fires though. Glad it worked for you though.

Thanks for the comments, it dawned on me this morning I had made an instillation error. The error was that I was thinking only one side of the fuse equation the male plug side requiring the power and not the female socket power delivery as per my photos.



Still these plugs are promoted as water proof, but none are fire proof as well. Yes my consern is that the 12 volt fridge is running all the time I'm not on board.



Yes luck was on my side this time, my simple error could realy have cost me my boat. this misshap it is a good sobering wakeup call, to check every instillation again with care.

[Maine Sail]

Originally Posted by kryg

Frankly I discovered that cigarette sockets are not heat or fire proof that is the problem when one experences a short, like I did.

It likely started as high resistance and as the plastic melted it possibly shorted.

As the springs in the male plug weaken over time, in the 12V+ tip and ground wings, the plug can develop a sloppy fit and work loose. When it becomes loose in the socket we create a point of high resistance which can begin to heat the plug and outlet to the point of fire all at well below a fuses trip point. I have seen this happen with a 15A rated fuse and the fuse never tripped because the owner was not exceeding 15A but the outlet was scorching hot and melting due to high resistance..

If you follow a few simple rules for 12V DC sockets they can be used in a safe manner.

#1 ALWAYS USE OVER CURRENT PROTECTION
#2 Max fuse size 7.5A (preferably not more than 5A)
#3 DO NOT plug in pumps, motors or search lights
#4 Choose high quality sockets rated for at least 15A (but don't run them at that)
#5 Contact points need to be kept clean (A Dremel works, 12V Power off first)
#6 DO NOT plug in small 12V to 120V inverters.
#8 If the male plug becomes loose fitting stop using it and replace it.
#9 Use only for cell phone, camera, tablet or laptop charging with 12V loads less than 5A - 7A

If you follow this you will likely never have a 12V outlet issue again. High resistance can start fires well below the fuse trip point!

Originally Posted by kryg

Thanks but I do not want to cut into the bulk head, my error was to rely on the fuse for the male plug in item and not the the female socket.

Absolutely and this is a major goof. Every wire on-board your vessel, not just a 12V socket, needs to be over-current protected.

[Maine Sail]

Originally Posted by kryg

Thanks for your comments After a good rain I'm using the 12 volt socket mostly to run a very small 4 amp powered pump to move rain water from my dingy which sits on the foredeck,into my boats 2 x 100 liter water tanks saves me going to the marina using town water.

I would suggest finding a better socket design if you want to use a pump with a 12V outlet.. Remember that 4A rating is often an un-loaded rating and every manufacturer rates these small pumps differently..

As an example a while ago I had a brand new Rule 500 kicking around my shop so I attached it to a battery... Rule recommends a 2.5A fuse for this pump. The fuse is sized to prevent the pump from caching on fire.

Battery = Group 31 AGM Resting Voltage 12.77V

Meter = Fluke 376 w/Inrush & min/max NIST Calibrated, Fluke 289 & Fluke Infrared Pyrometer

These are the tests I ran:

12.75V - Ran pump dry for 10 minutes and saw 1F rise (Fluke Infrared pyrometer)

12.72V - No Load (spinning in air) = 0.7A with no load (in-rush/startup current current = 2.7A)

12.72V - Pumping water, open bucket rate, no head pressure from hoses 1.34A (did not test with hoses, elbows etc. but would likely be a bit higher)

12.72V - Locked Rotor with a 3A Fuse = Blew Instantly

12.71V - Locked Rotor with 5A Fuse = Blew nearly instantly (about 6 seconds)

12.71V - Locked Rotor with a 15A Fuse = No blow 10.9A continuous draw, pump getting rather hot to the touch after 90 seconds of stalled rotor. Discontinued at 2 minutes and 10.7A (heat build up in windings likely caused current to drop a bit) bilge pump was at 136F, and climbing, at 2 minutes of stalled rotor.

12.70V - Locked rotor measuring inrush with 5A ATC fuse - Inrush = 10.9A - Fuse blew

You would be well served to use a DC clamp meter, or even a DVM set to 10A scale, in series, and measure the pumps actual current draw before continuing to run it off a 12V socket. As can be seen a 4A rated pump may not be a 4A draw. If it stays below 7A when pumping water it should be fine provided all contact points are clean and the male plug fits tightly.

[MarkJ]

Olives are healthy

[glenn.225]

Originally Posted by Maine Sail

It likely started as high resistance and as the plastic melted it possibly shorted.

As the springs in the male plug weaken over time, in the 12V+ tip and ground wings, the plug can develop a sloppy fit and work loose. When it becomes loose in the socket we create a point of high resistance which can begin to heat the plug and outlet to the point of fire all at well below a fuses trip point. I have seen this happen with a 15A rated fuse and the fuse never tripped because the owner was not exceeding 15A but the outlet was scorching hot and melting due to high resistance..

If you follow a few simple rules for 12V DC sockets they can be used in a safe manner.

#1 ALWAYS USE OVER CURRENT PROTECTION
#2 Max fuse size 7.5A (preferably not more than 5A)
#3 DO NOT plug in pumps, motors or search lights
#4 Choose high quality sockets rated for at least 15A (but don't run them at that)
#5 Contact points need to be kept clean (A Dremel works, 12V Power off first)
#6 DO NOT plug in small 12V to 120V inverters.
#8 If the male plug becomes loose fitting stop using it and replace it.
#9 Use only for cell phone, camera, tablet or laptop charging with 12V loads less than 5A - 7A

If you follow this you will likely never have a 12V outlet issue again. High resistance can start fires well below the fuse trip point!

Maine

Excellent points, I have used a wide variety of these in the automotive field and they do cause problems if lower quality or are misused.

[Salty Mike]

Originally Posted by MarkJ

Olives are healthy

Only if they receive the proper nutrients.

[Saltyhog]

Originally Posted by MarkJ

Olives are healthy

That was *my* take-away. When I eat olives, along with their natural pairing with gin, I feel good. The more olives I eat, the better I feel. When I stop eating the olives, I feel bad. By the next day I feel really bad, until I start eating olives again. The logic is irrefutable.

To add on topic content, the trolling motor connectors mentioned above are the easiest solution to replace any CL sockets to be used with a high draw accessory. They look like they fit in the same hole size as the CL socket, so are an easy upgrade. Perfect for a search light socket in the cockpit.

[leftbrainstuff]

Originally Posted by kryg

I just experienced my first Electrical fire after 28 years owning my boat.

I wanted to share with you, today’s experience, so boat owners who have 12 volt female socket on board take care. About two years ago I installed what looked like a robust 12 volt duel all-weather power point socket. Mounted in my galley bulk head.

Background: These ones are the best most robust one I could find. Over a few years of continued use I experienced no issues of over heating.

As I had in the past I had bought a number of what I thought was quality 12 volt power sockets from a Marine store. I discovered that after some use they showed signs of heat deformed internals at the wire soldered to connectors on the internal plastic wire mounts, they where not up to the job of daily use in fact proved potential fire danger. So I changed them.

What happened? As normal I plug in a small 12 pump into the socket, with in a few seconds a short occurred inside the 12 volt power socket the plastic shorted and started to burn its housing where the Positive and Negative wires internally wired and sealed by the manufacture.

The fire was so quick to ignite, it stated to burn the boats bulkhead in seconds. Even though I had a fire extinguisher next to the fire, it was quicker to put it out with a large jar of olives in brine. (in the clean up I'm still finding olives in the odd places) Instantly I knew had a I put the fire extinguisher into operation it would have spread far larger area and quicker into the boats wood work as the boat is fitted out in light weight wood laminated balsa core to keep it light.

See photos of failed 12 volt unit. Now I have three others on board I will need to find ones that can't fail like this one has if anyone has a brand that is fire and short proof please let me know.

For the first time I experience how a fire in a few moments can destroy a boat because of faulty design or workmanship, After the internal short of the internal wire connecters the fire took hold by burning the surounding plastic housing at athat point then the bulkhead started to burn. Frankly lucky I was standing a few feet from the ignition to put it out so quickly. .
.

No fuse?

Cigarette lighter sockets are a poorly engineered solution. They were originally designed for short duration high current and infrequent usage.

We've replaced most of ours with dedicated USB plugs and proper 2 pole connections.

Most cigarette lighter installs tend to be undersized in terms of wire size. Worth checking before use. Also look for hot spots on any high resistance connections.


Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[AD28]

It would be very kind of y'all to post links to good (inexpensive?) sources for the aforementioned 'trolling motor,' 'usb,' and '2-pole' connectors

thanks

[glenn.225]

AD28 Look at first page of thread.

[Salty Mike]

Might wanna check out these guys from time to time. They are an electronics clearinghouse of sorts, no telling what they will have. They have new stuffs and components that were taken from equipment.
And for LEDs as well
All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices

There are probably a hundred more just like them but these ones I have dealt with.

[basssears]

FWIW, I have had good luck with two pole trailer connectors... they're pretty simple, weather resistant (by no stretch weather proof), and you can get them in nice heavy gauges like 10ga:
Robot Check

Maybe someone with more knowledge can pipe up, I'm assuming I'm not going to get in too much trouble using these small stretches of wire - which I assume are not marine tinned - within a larger run of marine tinned wire?

-- Bass

[rwidman]

Originally Posted by exMaggieDrum

............. I would inspect the fuse holder and the fuse on this install to see if the fuse had shorted and was therefore routing current around it ............

A fuse is, in a sense, a "short". It is a conductor intended to melt when too much current flows through it. Once it melts, it is an open circuit. A fuse can't malfunction and route current around it.

[sartorst]

I don't know if this has been mentioned or not an application of dielectric grease or other anti corrosion agents will help prevent the arching as a component is plugged in which causes pitting which causes smaller contact area which causes resistance which causes heat which causes resistance bla bla bla. There is a heat dissipation factor by the grease also