Ok, I'm going to start to grow with a 400w MH light, but I've plugged it in for like 20 minutes and it gets really hot. I'm afraid if I leave it on all day like I'm supposed for two weeks it will start a fire somehow maybe. Do I need a metal cabinet to grow in or can I just put it in my closet? Do I have anything to worry about with the heat? Thanks for the input! Josh