This popped into my head as a result of two things - the desire to have a fixture to use my Advance LQ-106F-TP rapid start 4/6/8 ballast in, and the cannibalization of my 4 watt preheat strip light for other fixtures, which has stripped it down to just the body of the fixture and the Robertson L48 ballast.

My idea concerns a fixture that can be adjusted to run either a 4, 6, or 8 watt fluorescent lamp, and has both the rapid start and preheat ballasts inside it, and has a switch to select which ballast to run the lamp on. The switch would be a 6PDT unit, and as far as I can tell, I think I've found a wiring setup for it that would work. I've attached a picture showing the switch wiring diagram, as well as showing what the labels I've put on the switch refer to. The upper selection of the switch(es) are for the rapid start ballast, while the lower selection is for preheat. What do you think?

Assuming this electrically works, the only other obstacle would be building the body of the fixture. I don't have any tools to bend metal with. I do have a rotary (dremel) tool with a metal cutting wheel, so I could take any old T8/T12 fluorescent strip light and cut it down to the proper length (which would be 13 or 14 inches), although I don't know if such a small cutting wheel is meant to do that much metal. I see you can also buy metal hobby project boxes, so if I could find one of those that's the right size, that would do the trick. I could also make the fixture out of wood, but I'm weary of doing that because I would like to have as good a grounding as possible for the rapid start ballast.


Edit: I later found that I can possibly use a 5PDT switch, if I leave HOT connected to BLK all the time, and tap off it when I switch to preheat. I've attached another diagram.

I think the biggest problem would be to make a fixture, that could hold and connect any of the 4, 6 and 8W lamps...
I guess it will require manipulation with lamp socket.
So then Iguess it won't be easier to have two sets of lamp sockets there, each of them connected to one ballast and then one SPDT to switch the power to either of the ballasts...

Yeah, one lamp holder would be movable to accommodate all three lamp sizes. I could have two sets of lampholders for the two ballasts, but I would want the fixture to look as streamlined as possible.