A damp light bulb is never a good thing Sean. If the connection to the power at the end cap is staying dry, it is probably fine. I have a piece of glass or, I think you guys in the UK call it perspex, between the water and my light fixtures on almost all of my tanks. It keeps the lamps from becoming wet. That means that all that I need to worry about with my lighting is the bulbs and fixture staying cool enough. Proper vent openings provide all of the insurance that I need for proper cooling.