I had a lamp that broke recently after getting smashed against a wall by accident (there are now numerous exposed conductors, making it unsafe to use), so I went to the store to get a new one. I intend to use the same very nice LED bulb in the new lamp. I have measured the lamp's power consumption with the LED bulb as 15W before it broke, using a kill-a-watt meter. I was expecting to see a single power rating on each lamp, measured in watts. I was also expecting that that rating would be around 60W to handle old inefficient bulbs, hence making (nearly) every lamp usable with my LED bulb. Unfortunately, this is not what I saw. Most of the lamps had a separate rating for an LED an incandescent bulb, with < 10W for the former and around 60W for the latter. Some also had ratings with a similar < 10W wange for self-ballasted compact fluorescent bulbs instead of LED ratings.
What is the reason for these different ratings depending on how the electricity is used? Surely, if the lamp can deliver 60W to an incandescent it can deliver much less to an LED without problem? Can I use my 15W LED bulb in a lamp that is rated for an 8W led or a 60W incandescent?
EDIT: I think that this question is on topic as, although I am not a professional electrical engineer myself, this is important knowledge for anyone looking to design a lamp or other light fixture.