Thank you all for your helpful suggestions, especially the part numbers. This must be an older Lightolier fixture because the "can" connects to the line at a junction box that's fastened to the light frame that's nailed between the floor joists. The Thermal protector is inserted through a knockout in that junction box. So replacing the "can", if I understand that term correctly, doesn't replace the thermal protector. It has to be removed from the junction box, which is very easy. I will either buy the part or get a sacrificial light. As for the bulb wattage, it's less than allowed. The problem was with no light when first switched on, not the light going off after so many minutes of use. I assume these devices reset once cooled down. Possibly the shower ceiling location with its high humidity has accelerated the demise of this protector. Again, many thanks to you all for being so helpful.
