I am trying to do a simple low voltage lighting design. I intend to use 3 18w incandescent bulbs just to light a small area. I want to know if there is a problem using a 120w transformer for this or should I use something much smaller like 75w? The distance from the transformer to the first light will be about 20ft, and each light is separated by 10ft. As far as I can tell I should use 12gauge wire for this.
Again the question is should I use a 75w transformer or 120w transformer and what is the problem using the 120w if I should not use it?