Last year I had my power supplies and controllers inside and ran my cables out to lights. It worked fine but this year I need to have them outside nearer to my lights. I have the Masters $10 boxes that I bought last year and didn't use. I am a little concerned about ventilation/heat build up. All of my power supplies will only be running around 50%. I bought some of these from RS components. They will provide a little ventilation, but not much. Am I (literally) playing with fire by only providing such a small ventilation hole? I plan to have 2 on each box.