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Best 12v Cable for Indoor Lighting ?

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    I use 12 ga. most of the time for runs under 12-15 ft. It really depends on the load and the distance from the battery to the light fixture. The higher current (amp) demand, the thicker the wire..



    Another noob question…

    Whats the best 12v Lighting cable when using Solar power for indoor use.

    I’m assuming I can’t just simply use an existing Lights cabling as it’s 240V ac and the 12V system requires thicker cable ?

    Any help greatly approeciated.




    Did you guys know that the little 22 gauge wire that your telephones are using is carrying 48 volts dc and 90-100volts ac while its ringing and it goes for miles before the phone company uses repeaters to bring the volts back up. In highrise offices the volts are 24 and on 24 gauge wire. Unless you are pulling allot of watts on the other end, a light bulb can use 12 and under to be safe. But if it’s just an led then small wire is fine.


    I bought a caravan with two 240v lightbulb sockets mounted on the bottom of the cupboards wired with thick 240v cable. I wanted to replace the 240v bulbs with 12v directional mounted car sidelight bulbs. The idea to use them as reading lights. I simply cut all the 240v cables shorter (they’re still quite long), bypassed the original switch (my mounted 12volt lamps have their own independent switches on them), and used the original wiring directly as it was routed and connected it into the main load line that comes from my solar regulator and joins all the rest of my lights and appliances.

    It works fine and has saved me money on cable and hassle of re-routing the cable.


    Seeing the above comments gives me a sense that the correspondents generally lack any in-depth knowledge. 12V man at least know the rudiments of voltage drop as a function of current and wire length.

    I highly recommend anyone wanting to run 12V wiring first read one of the books on RV and boat wiring which includes at least a whole chapter on the subject and also includes some of the wiring tables used to determine wire size for a given length and load amps. I have seen too many examples of someone using any old wire they happen to scrounge but forgetting basic safety principles.

    Everything works fine until . . . . something unforseen goes wrong. In the absence of correct fuses in the right place, a short circuit can cause wires to overheat and melt the insulation. Most plastic wires are made using PVC which is highly toxic when melted. I know of one fatality where the owner was running some new wire and accidentally caused a short. The smoke from the melted wire overcame him before he could step six feet to the door and fresh air.

    AS a marine electrician I have seen my share of fires started by poor wiring done by owners who figured they knew enough. Enough to be dangerous is more like it! There are any number of good books published and available at public libraries if you can’t afford to buy them. It might save you from having a fire or worse getting killed by faulty wiring. Data wiring such as computer cables and phone cables should not be used for power unless the power source has protective over current protection installed. Using inadequate wire sizes means incurring losses that are worse than the losses you are trying to avoid by not using inverters.


    Wire sizing is all in the Pocket Reference, a very good $10 book to have.

    There is enough PVC produced yearly to kill everyone a hundred times over and it lasts up to 50,000 years in a landfill. The vapor killed him before he could take a few steps to fresh air. Wow! People think nuclear waste is bad. At least it can be used by GenIV reactors, while PVC is a long term threat.


    Hopefully you would be able to just ask at the store where you buy the cable – or a phone cal to any good quality hardware store should do it.

    Yes, 12V wire should be thicket but as elnav says above – do not leave it to guesswork. See the disclaimer below – we put it there for a reason.


    This is a wire gauge chart. Follow it and NEVER forget to put a fuse at the source..



    Phoneguy suggested using data cable. Don’t do it! I once ruined a data cable by letting it lay on floor too close to a heater source. Despite being a foot away the plastic inside melted and the wires shorted out. Temp rating and ampacity is important and using data cable for powering lights is not recommended. Even if it is low currrent LED

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