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+--- Thread: Max wattage in a light fixture (/showthread.php?tid=162785)
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Max wattage in a light fixture - DRR - 01-12-2014
Bought a new light fixture for my laundry room this weekend.
In the instructions it says max 60w (incandescent) and max 13w (cfl). Which is the equivalent CFL bulb in roughterms of lumen output.
My question is, why couldn't/shouldn't I put a higher wattage CFL bulb in there for more light? The concern is primarily heat, right?
Re: Max wattage in a light fixture - sekker - 01-12-2014
Heat and physical space.
Maybe the 13watt cfl restriction is because larger CFLs wouldn't normally fit?
I've regularly put 18watt CFLs in fixtures for a 60 watt incandescent without a problem.
Re: Max wattage in a light fixture - DinerDave - 01-12-2014
If it's enclosed, the CFL may be too big, mine is open, co I have
A 23W CFL to make up for the dimmer when cold effect.
Dave
Re: Max wattage in a light fixture - OWC Jamie - 01-12-2014
primarily heat
premature bulb failure
failure of fixture
failure of fixture wires
risk of fire
with a ceiling fixture: risk fire despite/of drywall
Have had a rental property ceiling fire from a 100 watt bulb in a ceiling fixture clearly marked 60 watt max
Re: Max wattage in a light fixture - deckeda - 01-12-2014
I think you might also find heat output differences among CFLs of the same wattage rating. It doesn't make sense, as watts used correlates to heat produced, but the shape and size of the base and/or any heat sink (like with some LED lights) can influence this. I'd look for one of the newer "micro" CFLs to at least cut down on space.
Re: Max wattage in a light fixture - space-time - 01-12-2014
primarily heat
please explain the reasoning. heat from a 13W CFL is about 4x less than heat from a 60W Incandescent. I would think you could safely put a 40-50W CFL if such thing existed and if it would fit in that space
premature bulb failure
what would cause that?
EDIT: OK, maybe there is a reason for this if the CFL is designed to operate in an open space and not it is enclosed, so the bulb may fail, but the fixture should be OK.
failure of fixture
why would the fixture fail? it sees less amperage and less heat with a 20-25W CFL than with a 60W incandescent
failure of fixture wires
again please explain this. the current is less than for an incandescent bulb
risk of fire
why? less heat, less current, what would start the fire?
Have had a rental property ceiling fire from a 100 watt bulb in a ceiling fixture clearly marked 60 watt max
that makes sense, 100W bulb in a 60W fixture is a NO-NO, but I don't see a good reason why a 20-25W CFL would not work. Or a 20-30W LED for that matter.
Re: Max wattage in a light fixture - OWC Jamie - 01-12-2014
space-time wrote:
primarily heat
please explain the reasoning. heat from a 13W CFL isaboutshould be 4x less than heat from a 60W Incandescent. I would think you could safely put a 40-50W CFL if such thing existed and if it would fit in that space
premature bulb failure
what would cause that?
EDIT: OK, maybe there is a reason for this if the CFL is designed to operate in an open space and not it is enclosed, so the bulb may fail, but the fixture should be OK.
I'd guess no manufacturer tests a fixture with a flaming failed cfl
failure of fixture
why would the fixture fail? it should seesless amperage and less heat with a 20-25W CFL than with a 60W incandescent
failure of fixture wires
again please explain this. the current is less than for an incandescent bulb
again, heat can bake wire insulation and any other insulation / parts within or comprising the fixture
risk of fire
why? less heat, less current, what would start the fire?
a cfl can catch on fire when it fails
I've had a cfl set off a smoke detector minutes before it started belching smoke - this was in an open fixture and was a properly rated bulb for an open fixture over a sink
Have had a rental property ceiling fire from a 100 watt bulb in a ceiling fixture clearly marked 60 watt max
that makes sense, 100W bulb in a 60W fixture is a NO-NO, but I don't see a good reason why a 20-25W CFL would not work. Or a 20-30W LED for that matter.
I would try it, and I have. I'm also not a lawyer nor was I consulted to word the lamp's warning label :-)
also:
One can take a 60 watt incandescent and actually test a fixture with it and reasonably assume that that one bulb represents all incandescents and ( maybe even ) all future incandescents. ( especially considering they are being phased out world-wide.)
You can't take a 13 watt cfl off the shelf and reasonably assume it represents all 13 watt bulbs because it doesn't, nor can one assume that any future manufactured 13 watt cfl won't generate an amount of heat that the fixture can't handle either
One can reasonably assume it shouldn't, but you can't absolutely warrant that it won't.
Technically you can't really assume a future 12 watt cfl or LED or whatever, but any future manufactured bulb that might put out more heat than an equivalent should also have a use disclaimer.
Re: Max wattage in a light fixture - cbelt3 - 01-12-2014
Cfl bases get really hot . So can LED bulbs.
Re: Max wattage in a light fixture - DRR - 01-12-2014
space-time wrote:
primarily heat
please explain the reasoning. heat from a 13W CFL is about 4x less than heat from a 60W Incandescent. I would think you could safely put a 40-50W CFL if such thing existed and if it would fit in that space
premature bulb failure
what would cause that?
EDIT: OK, maybe there is a reason for this if the CFL is designed to operate in an open space and not it is enclosed, so the bulb may fail, but the fixture should be OK.
failure of fixture
why would the fixture fail? it sees less amperage and less heat with a 20-25W CFL than with a 60W incandescent
failure of fixture wires
again please explain this. the current is less than for an incandescent bulb
risk of fire
why? less heat, less current, what would start the fire?
Have had a rental property ceiling fire from a 100 watt bulb in a ceiling fixture clearly marked 60 watt max
that makes sense, 100W bulb in a 60W fixture is a NO-NO, but I don't see a good reason why a 20-25W CFL would not work. Or a 20-30W LED for that matter.
That's my point, I should be able to put a higher than 13w CFL in there because it puts out much less heat - but the manual says 13w max and I'm trying to understand why.
Re: Max wattage in a light fixture - deckeda - 01-12-2014
Yeah but I think you need to be "more certain of your assertion" here, because the situation is backwards ... the bulb makes less heat than an incandescent but the base makes more than an incandescent's. You could say that with CFL, "all" of the meaningful heat comes from the base and some gets transferred to the glass.
I've often used "higher wattage" CFLs in fixtures assumed to be using incandescents and the house hasn't yet caught fire. I do think that on average they run cooler.
Bottom line (for me): Do an informal heat test. Run the bulb and feel for heat. If it feels hotter than what you remember a 60w incandescent to be, remove it.