Strange this came up, I just completed a homemade hatcher today. I use the light sting that has several bulb holders, like you use in those Christmas village sets. I am using a 7 watt night light and a 15 watt bulb. The string has a circuit fuse build in. It makes me fell better with that in there. You do need to be careful and place the bulb low enough in the box so it will not get to close to the foam and overheat. I don't have a fan in the box and I don't need a turner so there is only one connection. I guess I could go haywire but the logic of the wiring does not lead me to believe it is any more likely to catch fire than any other low watt lamp. I used a box from a Lobstergram that came at Chrismas. It is 2" styrofoam and hold heat very well. I am testing it now and then I will make whatever adjustments I need. I have to cover the thermostat yet but I feel pretty comfortable with it.