If you have several 12volt
camp lights, each with their own switch around the camper
trailer, it is very handy to have a central location to operate
them from to avoid fumbling in the dark. While cigarette sockets
& plugs are fine for what we use them for around camp, they do
have a tendency to break contact through road vibration while
driving. Hella/Merit style plugs & sockets or Anderson connectors are best suited in this situation as
they provide a more positive fit.
It seems whenever I do a
12volt project I need to run around to at least a half dozen
shops, however in this case Jaycar had everything I required so
it was just a one stop shop.
As the switch box is only
going to be used to operate our LED lighting with a very low
power draw, a cigarette plug with an inbuilt 3amp fuse was all
that was needed.
You could set the box up
as a 12volt power point to run your laptop 12volt power supply,
12volt battery charger for a phone or camera if needed. In that
case you may need a heavier cable depending on what accessories
you want to run & also take the distance from the main outlet
into account. Narva make a suitable 15amp fused cigarette plug
with wires connected via screw clamps - part number 82110BL.
The Solar Wind online calculator is an easy way
to work out what size cable to use by placing the amp draw of
the accessory & cable length
Wind has given campertrailers.org permission to reproduce
the cable size calculator found on their website.
There are plenty of on/off
switches to choose from. I liked the LED illuminated rocker switches rated
at 30amps mainly because the buttons do not poke out to be
broken off rattling around in the camper when travelling & they
have a screw fitting to keep them in place, rather than just
The 15amp wire
twin core auto cable was more than enough for the
job. I mainly went for this as the two cables are sheathed. A
wiring diagram can be found below.
The red insulated crimp
terminals are suited to the 15amp auto wire, but need a blue
insulated crimp terminal for two wires. Alternately you could
use a red piggy back insulated crimp terminal that has a male as well as a female terminal on the one fitting.
I used a red insulated
crimp eye terminal for connection to the cigarette socket
positive by simply unscrewing the nut. Make sure the insulation
washer is properly seated before retightening as it can earth on
the socket body blowing a fuse. The cigarette socket has a
negative male tab for the earth wire connection with an insulated
female spade terminal.
Luckily there were two
screws on the stone guard in the right position so I made slots
in the back of the jiffy box to mount it from in camp.