On Fri, 15 May 2009 19:19:05 -0400, Wes wrote:

I bought an inexpensive 4' T8 dual tube light at home depot, they still sell it, 19.99
with an electronic ballast. Well, it crapped out a couple days ago, actually it was
flaky as in sensitive to temperature for a couple weeks. It lived a week short of 4
years.

I ripped it apart, ohmed out the pre heat filaments in tubes and googled the ballast
manufacturer. Sunpark, SL25CW, a 6 dollar ballast. Looking for other replacements had me
in the 20-30 buck range. Sunpark would mail order me a unit for about 17 bucks when you
figured shiping.

Probably Sunpak, a big player. You do NOT need to go with an exact
replacement, as long as it's a UL rated component use what you can get
easily and reasonably. GE, Sylvania, Fulham Workhorse, Motorola,
Advance...

Unless you have special needs or an odd sized fixture that needs an
odd size ballast (undercounter T5 strips) they are mostly the same -
the more you pay, the more likely to get better components and it'll
last longer. But not always.

So I stopped by HD, the only show near where I work and looked for ballasts, I found a GE
model on sale for 15 bucks. Longer, heavier, likely better. Noticed the light I have is
still available for 19.95, likely with the same ballast.

I went for the GE. Might as well limit solid waste going to the dump. I recycled the
lighting unit.

Yeah, the entire strip brand new can be LESS than the replacement
ballast, and you get fresh lampholders. Especially if it's an odd
ballast like an F20T12 instant start that isn't a big mover.

But it's still wasteful - and while I don't have room on the truck
to cart around 100 different variations of strips and wraps and
troffers on the odd chance I'll need one, I can always make room for
the dozen most common ballasts and lampholders.

Tonight, I realized that there is a lot I don't know about ballasts. The old one used the
filaments to preheat. This one had three wires going out. One side of the two tubes have
all pins wired together, the other side has a wire from the ballast going to each of the
two pins paralleled together.

I did the google and the wiki thing. Looks like the filaments don't have to be heated to
start the light. That simplistic wiring diagram was giving me pause.

I learned something today.

The first day you don't learn something new, that's the sign it's
time to start shopping for a nice cemetary plot on a hill...

Today's Lesson: You do know the Paper Clip Trick right? Straighten
out one leg of a small clip one turn, and stick it in next to the wire
to get the old wire out of the lampholder Easy-Peasy.

The new lampholders they ship with those two-wire electronic
ballasts (one wire to each end of the lamp) have the shorting bar
built in between the two pins. The electronic ballasts don't need to
preheat the filament to get it started, they have enough of a HV start
pulse - and it saves the 4 to 6 watts used to heat the filaments.

Now you have to be careful not to get them mixed up with the
old-style two wire lampholders used with standard magnetic ballasts -
they are marked, but sometimes that's only little letters molded into
the white plastic and Not Easily Seen unless you know to look.

The split old ones are easily jumped with a short piece of wire for
a new electronic ballast, but the other direction isn't possible.

Follow The Diagram and the Approved Lamp List on the Ballast Label
(or the cut sheet), Every Time. They are coming out with new
variations every month, and they all go together different. Like
using a 4-lamp electronic ballast as replacement in a 3-lamp fixture,
sometimes it matters which "extra" wire you cap and leave unused.

Used to be the only real oddities were the switch-style Disconnect
lampholders sold with the Preheat Magnetic one-lamp strip ballasts -
Advence RL- series. Found in elevators a lot, they open the Neutral
from the Line and the Neutral to the lamp and ballast when you take
the lamp out.

They usually have a BIG black D (for Disconnect) rubber-stamped on
the rear cardboard insulator - but not always... The other clue is
there are two white wires on the Disconnect side (one marked Line in
the plastic and the other one Ballast) and a Blue with White stripe.

-- Bruce --