"It is the first responsibility of every citizen to question authority." B Franklin
You're welcome. I only knew about the rating because of some work I did on a houseboat.
If Billy Idol or John Denver is on your Ipod go and re-evaluate your life.
Thank you for your replies.
As always I learned something.
Education is a progressive discovery of our ignorance.
Exceptions are cold cathode lamps and novelty carbon filament fluorescent lamps. The filaments in fluorescent lamps are for not just for pre-heating. They allow the cathode coating to operate at thermionic temperatures.
Even though they're not energized, high temperature cathodes are crucial for long life and performance. When they're dimmed to the point of not being able to sustain optimal temperature, they have to be heated by energizing them or the lamp will sputter and fail rapidly.
As for across the line type bulbs, they have a considerable inrush current. When a 500W work light is plugged in, there is a noticeable voltage drip that is enough to dim other lights on the same branch. As such, many plug-in consumer switch/control devices have three ratings, motor, resistive and tungsten. The tungsten wattage rating is lower than resistive load.