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Don Klipstein Don Klipstein is offline
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Default Replacing fluorescent bulb

In article 7KSPi.59$et1.47@trnddc02, Pop` wrote in part:

Maybe. Pull the outside cover and glance at the ballast inside: It will
usually state what wattage lamps it's designed for. It may be rated to
handle it, or may not. From 25 to 32W is a little "iffy" for new fixtures,
more likely to be OK for older ones, but check anyway unless you're willing
to replace it if you're wrong.
Or, you could just replace the ballast at the same timeg.


Note: 25 and 32 watt 4-footers have significantly different
ballast output voltage requirements. A 32-watter may have starting
difficulties or flickering or unsteady brightness where a 25-watter works
well, due to ballast having lower output voltage and lower output
impedance. The 32-watter requires more ballast output voltage and more
ballast output impedance than 25, 30, 34, 35 and 40 watt fluorescents
require.

BTW: Are you sure it's 25W and not 22W? Just asking. Anyway, if you can't
find out what it's rated for, wait for the right bulb, IMO.


I have yet to hear of a 22 watt 4-footer. In my experience so far, 22
watt fluorescents have only been "circline" ones of circumference a little
over 2 feet. I have even seen a few ballasts for those that are also
rated for 20 and 15 watt fluorescents, sometimes also 14 watts,
occaisionally also 13 watt T8, but never rated for over 22 watts when
rated for multiple wattages unless appearing to me to be
"circline"-specific.

On a bit of a digression, I do want to add:

1. Most "circlines" have "older tech" phosphors, and color rendering
index usually close to 62 (usually 50's for warm white).

2. The multi-wattage ballasts rated for 15 and 20 watts, including those
also rated for 22 watts, in my experience tend to supply about 16 watts
to 20 watt "bulbs" and 16-17 watts to 22 watt circline "bulbs". I have
also seen a few ballasts rated for 20 watt "bulbs" and not for lower
wattages similarly underpower 20-watters (and 22 watters when rated for
those and being used as directed).
Expect 20 and 22 watt traditional size fluorescents to normally only
slightly outshine 15 watt traditional size ones, and to often fall short
of claimed light output by 15-20 percent!

- Don Klipstein )