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Don Klipstein Don Klipstein is offline
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Default Replacing fluorescent bulb

In article 5OSPi.60$et1.54@trnddc02, Pop` wrote:
DerbyDad03 wrote:
On 12 Oct, 13:46, "sinister" wrote:
Light went out in the bathroom. It's a 48" 25W T12 GE fluorescent
bulb.

I can get one online, but I'd rather rush it and buy one in a brick
and mortar store. Problem is that they only have 32W and 40W. Does
that matter?

TIA,

S


It *could* matter for 2 reasons:

1 - The fixture might not be rated for the higher wattage. There
should be a label on the fixture stating the maximum wattage to use.


"Fixture"?? No. Ballast, maybe, but not the fixture.


2 - Assuming the fixture can handle one of the higher wattage bulbs,
the question is - can you? If you're used to 25W and are comfortable
with the lighting effect, then 32W or 40W might be too bright,
especially in a bathroom in the middle of the night.


It's unlikely a 25 to 32W bulb's brightness is going to be much perceived
and certainly won't be a problem. Just going to a new 25W bulb will likely
make a nice increase in the light output but not much different than a new
32W would. 40W is stretching it and I'd seriously doubt the ballast would
handle it.


32 watt bulbs are a different animal, requiring more volts and less amps
than 25, 30, 34, 35, and 40 watt ones. OK, maybe about the same amps as
25 watt ones, but more volts.

It is safe for the ballast and fixture to put a 25-watt bulb in if the
ballast is rated for any or any combination of the other wattages that I
mentioned, as long as you donj't get obvious malfunction.

If the ballast is rated for 25 watt bulbs and appears to run a 32-watt
one OK, you should be OK. Bulb life may be compromised, though I think a
little more likely not.

The main issue then becomes liability should the ballast burn the place
down anyway, even if for reasons other than not being used as directed
(such as being a low quality stool specimen, or misused by the landlord by
being in a fixture not meeting possible ballast requirement of the fixture
to be suspended in mid-air like a shop light). UL listings are invalid
when eectrical equipment is used in a manner violating instructions that
come with them, such as using lamps/"bulbs" other than ones that the
ballast label/nameplate says that the ballast is rated for, or a different
number of lamps/"bulbs" than one/ones the ballast label/nameplate says the
ballast is rated for.

My experience suggests to me that fixtures for 25 watt 4-footers are
el-cheapo cheapies, and I have dim expectations of the kind of ballasts
that go into those.

- Don Klipstein )