Does anyone know how hot these lights can get without catching on fire? I am almost positive that I have a ZooMed 5.5" dome fixture that Zoomed says will support up to a 100 watt bulb. I have a 100 watt bulb standard incandescent bulb in there and the dome gets upwards of 220 degrees. Is this okay? I am a little uneasy with it. My other domes (albeit a little larger, but have larger bulbs) only get around 160 or so.