Wiring specialists..?

In a message dated 95-11-08 16:02:16 EST ,Greg. Tong writes:

>Would someone be able to show me whether a four-lamp electronic ballast,
>*parallel* rapid start can be wired to support two switches? What I would
>like to do is use the one ballast to power two pairs of lamps but be able
>to switch each pair on and off independently of the other.
>Is it possible? And how?

When I was once young, I tried this unsuccessfully. When you place any
'normal' switch across one of the wires running to the lamps the electricity
just arcs across the switch. It seems like you would need a knife switch to
separate the contacts adequately but then your dealing with high voltage
exposed metal. Not a nice combo - especially w/ water near...  <zap>
>At my local GE store, one four-lamp electronic ballast costs as much as one
>two-lamp electronic ballast. So there is money to be saved but I'd also
>like to fiddle with only one ballast if possible. Thanks.
Although it would be somewhat of a pain, you can remove the lamps completely
and the remaining ones will stay lit. This is my tentative plan.  Most of
what I'm reading seems to indicate 2 lamps as a minimum over a 55 (or 40
long), with 3 being better and 4 (maybe) too much - depending on the system
set up and the plant species.

This brings me to a question I've had - why are lighting intensities listed
in watts per gallon rather than something involving lumens or candlepower?
The normal 40 watt T-12 fluorescent has fewer lumens output and a higher
degradation rate than the new T-8  32 watt lamps. When I see the watts per
gallon estimates, should I assume that we're referring to the standard T-12
 40 watt lamps?

Ron Lane
whirlabout at aol_com