I would add that it is a good idea to use tinned wire. This wire has a coating of tin over the copper. It really helps for corrosion protection, the wire only costs a little bit more. If you have trouble finding it you can order many sizes and colours from Digikey - digikey.com. Great people to deal with.
I have an Alpha Chart, Rough gauge sizes vs amperage, note this is when the insulation melts.
30 ga 2-3 amp
24 ga 6-8 amp
18 ga 15-18 amp
16 ga 19-25 amp
14 ga 27-33 amp
12 ga 36-45 amp
The amperage difference depends on the insulation.
These are single conductor in free air ratings, for a bundle of 2-5 derate x.8, 6-15 derate x.7.
Hope this helps
David
