electrical drama

[shanejohnson]

With the bad weather thaught i would tidy up some wiring in the tinny which was over due. The setup has a swith board with 4 switches which is fed with a positive from battery. Another positive feeds sounder and ciggy plug. Everything is fused.All negatives go to negative earth block. I proceeded to cut a hole in the aluminium seat to fit swich board and continued to connect up everything. Then connected the battery back up and was happy all worked. After a while i could smell burning plastic and could see smoke coming from outboard leg. So i quickly disconnect battery pull swich board out ; all looked ok so connect battery back up and all worked ok thankfully. The platic coating on the wire on the outboard leg melting is the only damage i can see.I guess it is earth wire,dont know. Outboard starts ok and everything else works. The only think i can think happened is back of swith board touched aluminium seat. Anybody Know how i f.....d up and have i damaged outboard.
shano

[SNAPPERCOFFIN]

I would say you put a positive charge through the boat make sure none of the wiring you refitted is touching the boat.

[shanejohnson]

Thats what i'm thinking happened, just dont know where .Does it matter that the wire on the outboard leg is now bare. Guess thats why we should carry fire extinguisher on board.

[SNAPPERCOFFIN]

Disconnect the wire on the outboard put some heat shrink on and replace.

[Angla]

It sounds like you have pinched a positive wire when you put the switch panel back or you have put a screw into a wire. Then you removed the problem when you took the screws out and removed the panel. If it is easy, it may be worthwhile to put a thick plastic bag or the terminal area of the panel before you fix it back in. This will act as a thin insulating barrier as well as a wet protection.

Cheers
Chris

[shanejohnson]

Ahh a screw through wire didnt think of that. thanks fellas , good advice.

[Sea-Dog]

After making repairs to the wire insulation in the outboard and reinstalling switchboard - get a multimeter and check to see if any shorts before connecting battery.

A purchase that I'd recommend is the "12 Volt Bible" book from most ships chandlers. ie Bias, Whitworths etc.

Lots of good info in that book.

[shanejohnson]

thanks for info. seadog how do you check for shorts with multimeter. i think the hole cut in seat was to small and side of switch touched the aluminium. i cut hole bigger ,put it back together and seems fine now but would like to check it out further.

[Sea-Dog]

thanks for info. seadog how do you check for shorts with multimeter. i think the hole cut in seat was to small and side of switch touched the aluminium. i cut hole bigger ,put it back together and seems fine now but would like to check it out further.

** Disclaimer** I am not a qualified sparky - use the following suggestions at your own discretion.

These are a few methods that may show an electrical fault. If you are not confident with your results - seek the assistance of a professional marine electrician.
Both battery cables disconnected from battery
Set the multimeter to continuity (Ohms)
All switches in "Off" position (except master battery switch, which should be "on")
Hold one probe of multimeter on positive battery lead
Other probe touch to boat hull - Should be no reaction from meter
One probe on pos lead, other on neg lead - Should be no reactionIf multi meter shows zero Ohms upon touching either the hull or the negative battery lead - you have a short somewhere between the battery connection and the powered side of the switch panel.


That should take care of the wiring up to your switch panel - up to the powered side of the switches.

Now to test the load side of your panel...
One probe to Pos battery lead, other to hull.
Turn on each switch on the panel one at a time
Should be no reaction from multi meter.If you find the multimeter suddenly shows zero Ohms upon throwing one of the switches - then you have a short somewhere between the load side of the switch and the device.

The 12 volt bible says that there may be a very high resistance reading, just by virtue of the wiring existing in a damp, salty environment.

I urge you to go out and get the book and have a good read. It taught me a lot about both theoretical and practical aspects of electricity.

[welder]

I would REPLACE any wire that has burnt the insulation off . Use Tin coated wire and weather proof your connections .

A burnt wire will deteriorate very quickly .

The 12 Volt bible mentioned above ^^^^^ is a excellent suggestion .