Wiring and switches for interior lighting

[cmm303]

I am going to install extra LED lighting inside. I have seen lots of info here on LED lights but could do with some advice on the right cable to use (specs and colours if important) and best place to buy from.

I could also do with a good source for appropriate two and three position switches.

Thanks
Chris

[jimmo62]

You can work out the cable size you need from the rating of the LEDs. Take the total power of the LEDs connected to the cable and divide by 12 to get the current. Then double it and buy the next highest cable rating. Cable freely available on ebay from many sellers. Colour does not matter but use different coulours for different LEDs so you can trace wiring if there's a problem. Make sure you put a fuse in the circuit (as close to the battery as you can) of a rating lower than the cable but higher than the current you calculated above.

For example if you have 4 LED spotlights of 5 watts each your total current would be 1.67A. Use 16A rated cable (because it's a sensible size to push through gaps etc, smaller cable tends to be too flexible and is easier to tangle up) and a 3A fuse.

Switches also freely available on ebay, check the current rating is sufficient but for LED lighting you should be OK with most models

[dom_e]

...and remember, if you're wiring direct from the leisure battery (or starter), put an in-line fuse in close to the + source.

[cmm303]

Thanks. I am comfortable with the current calcs (I recall my W=VI and V=IR stuff!) but am not sure how current capacity maps to cable diameter and whether there is anything about the insulation I need to be aware of for an automotive application.

I was thinking of utilising existing light feeds which I was going to convert to LED to avoid overloading the existing wiring. LED conversion of flourescent light takes 1/3 to 1/2 the current. I am planning two additional cabin down lighters to replace little one in the corner at the back, 2 in the tailgate and one by the sliding door. Probably need to do the maths as I am relying on intuition at the moment.

[jimmo62]

1mm sq cable is rated at 16A. Get multi-strand as it's more flexible. Nothing special needed on the insulation front, as it's low voltage.

[cmm303]

Thank you