Quote Originally Posted by khronik
The wire size you can use depends on the amps. You need to know the gauge of the wire to calculate a safe amperage for it. You can calculate amperage from watts and volts, if you have to. 14 gauge wire can support about 1500 watts, so that's probably overkill, but it will work.

18 x 24W / 120V = 3.6A

If I could use a lighter wire, it would be easier to hang them, but I'll probably use those 6' extension cords from the dollar store. They're 14 gauge, right?