I bought a pack of two flourescent light starters this weekend, and bought
myself a puzzle into the bargain.
They are General Electric starter switches type 155/500 and the rating is
shown as 4 to 65W in big characters.

It also has three symbols on the pack:
- a warning triangle with a ! in the middle (okay, important stuff here).
- a little drawing of a strip light with 4W - 65W across it and a big
comforting tick (just what I want for my 10W and 30W fittings).
- another little drawing of a strip light with 50W across it and a big
cross against it (Eh?).

How come that it will do 4 to 65W but not 50W? What am I missing, and
what does it really mean?

Phil