size of 12v wires?

[jonnyboy1958]

Hi all, I need a bit of help. I am converting my t260 swb transit 2001 into a camper and wish to fit the ceiling soon before it gets the rest of its wiring completed. Now the only lights I need in the ceiling are four 12 volt led's so I want to run a conduit tube with wire through it for the four light fittings (to connect at a later date) My problem is what size/ampage cable should I use? or otherwise what size wire is acceptable for just the lights? As always I look forward to your words of wisdom, jon baker!

[Beaker]

Hi Jon,

Size is dictated by Amperage. You need to know how many Watts the LED lights are rated at, but if you say they are (for example) 6Watts total, then using the formula P=IxV, turn it round to get I=P/V. So I=6/12 = 0.5Amps.
You need to overate your cable for safety, but 1mm cable should be good for around 8Amps, so you can see 1mm cable is more than enough to do the job.

I have just used 21Amp 2.5mm cable for everything in mine as it's rated high enough for all my electrical needs, and 2.5mm is much easier to work with.

Basically use 2mm or 2.5mm for all your low to medium power appliances and you will be fine.

Of course if you want to fit a 1200 Watt microwave, you are going to need some big cable - 1200/12 = 100 Amps!

[jonnyboy1958]

Thank you for your reply, I will use 2.5 cable for the lights now. thanks jon.