12 volt led lighting wire size?

I'm in the process of wiring some led lights in a small 12 volt setup. There will be 10 6 watt lights, of which only 2 or 3 will be on at any one time, but if they are all on at once, it will be carrying 5 amps. What size wire do I need to use?

Thanks.

 

Old rule of thumb was for 1000 feet of copper at room temp, #10 1 ohm, #12 1.5 ohms, #16 4 ohms, since voltage drop is current time resistance , the drop for #10 would be 1, and the drop for #16 would be 4 times as much. Grand dad beat some things into my head 70 + years ago and I have used them all my life. The old fire and ashes are hot, black and red, snow and grass are cold, green and white, never trust an armature, always growl and check continuity, when turning an armature, never take off more than a couple thousand as copper smears and you will have a really hard time undercutting. Old motors, brushes and bushings built in 1920's etc lasted for ever but had to have work done on them almost ever year. Wish I had your knowledge of generators BTPost, old ones were a pain but could be rebuilt, new home owner brush less either work or you throw them away.

 

Just about anything will work for that, I use stranded THHN 12 for most everything interior and put it in conduit.

Here is a link to a size/amp chart: http://www.usawire-cable.com/pdfs/NEC AMPACITIES.pdf

 

This one is more suited for DC applications :

Wire Sizing Tool for 12, 24 and 48 Volt DC Systems

...or go with BTPost's recommendation...12 ga romex would work fine for your stated application

 

Actually that makes a lot of sense. You could match your wire size exactly to the load, but sure as heck one day you will want to add something and you'll have to upsize your wiring. Why not start off with wiring that'll handle almost anything you can throw at it from the outset?

Just remember that everything has its limits, and #12 is usually good for about 20 - 25 amps or so. Still, you have plenty of grow room without having to run wiring again if you add more lights or a small fan, a 12 volt blender, ... or something.

 

I can appreciate and understand the reasoning behind advising wiring a cabin with 12-2 Romex. However, low DC voltages draw much higher amperages than do higher AC voltages, which has been previously mentioned. Not to mention, they also suffer much higher voltage drops over long runs.

I would suggest calculating your runs, round trip, and at a maximum of a 3% voltage drop across the entire run. That is, unless you know, without any doubt, that you will not need any heavy DC loads on those circuits in the future.

My two cents worth.

 

Most of my loads will be on 12 feet runs or so. The lighting will be on a dedicated circuit of longer runs. Lights only.