Wattage rating of lights

[jimmy_mcquade]

Hi all,

most of the light fixtures in the house is rated 60 watts.

I understand that light bulbs are rated in wattage, and they give off heat.
I also know that watts is a power rating.
does the wattage of a light bulb mean that this is the amount of heat they are giving off?

the reason I ask is that with the new energy efficient bulbs you get more light for less wattage.
for example, a 100 watt bulb uses only 53 watts of power.

following that logic, does that mean I can use a 100 watt energy efficient bulb that uses only 53 watts of power in a light socket meant for 60 watts?

am I on the right track or a I missing something?

thanks,
jimmy

 

[A/A Fuel GTX]

I would say yes but others may disagree.

 

[mgookin]

Hi all,

most of the light fixtures in the house is rated 60 watts.

I understand that light bulbs are rated in wattage, and they give off heat.
I also know that watts is a power rating.
does the wattage of a light bulb mean that this is the amount of heat they are giving off?

the reason I ask is that with the new energy efficient bulbs you get more light for less wattage.
for example, a 100 watt bulb uses only 53 watts of power.

following that logic, does that mean I can use a 100 watt energy efficient bulb that uses only 53 watts of power in a light socket meant for 60 watts?

am I on the right track or a I missing something?

thanks,
jimmy

If someone is selling you a light bulb saying it's a 100 watt bulb that uses 53 watts of power, they are a liar. If it uses 53 watts of power, it's a 53 watt bulb. It may give off light of a magnitude similar to a 100 watt incandescent but it would still be a 53 watt bulb.

Your question is whether you can use this 53 watt bulb in a luminaire rated 60 watts. The answer is yes.

 

[Besoeker]

Hi all,

most of the light fixtures in the house is rated 60 watts.

I understand that light bulbs are rated in wattage, and they give off heat.
I also know that watts is a power rating.
does the wattage of a light bulb mean that this is the amount of heat they are giving off?

the reason I ask is that with the new energy efficient bulbs you get more light for less wattage.
for example, a 100 watt bulb uses only 53 watts of power.

following that logic, does that mean I can use a 100 watt energy efficient bulb that uses only 53 watts of power in a light socket meant for 60 watts?

am I on the right track or a I missing something?

thanks,
jimmy

The difference is efficiency. Some figures off the top of my head - others may refine them.
Incandescent bulbs are very inefficient at converting electrical energy into light. Most of it, possibly 95% or more, is dissipated as heat.
CFL's are much more efficient. That's why you get the same light output for a much lower input power. A 15W unit gives me as much light as a 40W incandescent.
LED units are another step up in efficiency. More efficient therefore lower wasted energy as heat.

A slight caveat. The CFL and LED units rely on a bit of electronics and that can't be allowed to get too hot so they are unsuitable for some kinds of fittings.

 

[Smart $]

Also yes.

The wattage rating is the power utilized, which is converted to light and heat... yet it all ends up as heat, just not as much localized to the fixture.

 

[GoldDigger]

The 53 watt bulb with high light output will actually generate less heat in the fixture than a 53 watt bulb with lower efficiency would.
I used to think that a halogen bulb with its high capsule temperatures would get the fixture hotter but that will not actually happen. The most that would happen is localized hot spots in different places than with a traditional bulb.

Tapatalk!

 

[jimmy_mcquade]

another question please.

so when a light fixture says its rated for 60 watts, that means its rated for 60 watts of power.

what will happen when you put a 150 watt light bulb in the 60 watt fixture?

I am asking because we do rework in which we find these light bulbs in the fixtures.


thanks again,
jimmy

 

[Besoeker]

another question please.

so when a light fixture says its rated for 60 watts, that means its rated for 60 watts of power.

what will happen when you put a 150 watt light bulb in the 60 watt fixture?

Most likely it will overheat or worse.
Bad idea.

 

[junkhound]

what will happen when you put a 150 watt light bulb in the 60 watt fixture?

If your light is in fixture in a barn in northern Alberta in the winter when it is -40 deg outside, it will be OK.

In a house at 20C or 70F the bakelite lamp holder will crack and fall off, the white wire in the box will turn brown, and there is a distinct possibility that a lead to the lampholder will oxidize and fuse open after awhile.

In Phoenix without AC on a 125F summer day, fire is a possibility.

 

[Rampage_Rick]

I'm starting to see ceiling fixtures that are marked max 60W incandescent / 13W CFL

 

[A/A Fuel GTX]

I'm starting to see ceiling fixtures that are marked max 60W incandescent / 13W CFL

So that kinda puts some rain on this parade. That's what I was afraid of.

 

[mgookin]

I'm starting to see ceiling fixtures that are marked max 60W incandescent / 13W CFL

I don't see how that can be logical. There are two reasons for power limits on ceiling fixtures and they are 1) heat generated and 2) ampacity of the conductors.

Do you have a manuf. model number for one of these so labeled fixtures?

 

[GoldDigger]

What I suspect is that at least part of the cause is not that the fixture will be damaged but that there will not be enough ventilation to adequately cool a higher wattage CFL, which is more temperature sensitive than an incandescent.

Tapatalk!

 

[Rampage_Rick]

I don't see how that can be logical. There are two reasons for power limits on ceiling fixtures and they are 1) heat generated and 2) ampacity of the conductors.

Do you have a manuf. model number for one of these so labeled fixtures?

It was probably implemented by some bean counter who saw that a 13W CFL has a 60W equivalence. If you google "max 60w 13w cfl" a bunch of people ask this question but nobody seems to have an answer.

 

[Besoeker]

What I suspect is that at least part of the cause is not that the fixture will be damaged but that there will not be enough ventilation to adequately cool a higher wattage CFL, which is more temperature sensitive than an incandescent.

Tapatalk!

Hence the caveat in post #4.

 

[Besoeker]

Somewhat related, this came into my business email today.

Dear UV LED specialist,
LED News Korea (www.lednewskorea.com) is pleased to inform you that we will have UV LED Show 2014 on April 18, 2014 in Seoul, Korea. Featuring exhibitions and demos, the one-day event is the first one of its kind as a full-fledged B2B round-table show.

Well, you can make presence there as an exhibitor or a demonstrator, and event details are available here. There is an early-bird discount of 20 percent off the registration fee: on Feb. 14. Philips Lumileds has already confirmed to join it, and LG Innotek is also considering a final decision of its exhibition size.

As Display Plus (www.displayplus.net) for global EE designers supports the event as a media sponsor - in fact, it is our sister publication -, it will have UV LED Special e-newsletter next week. You can contribute technical articles and flagship product introductions there, for free.

The links may have some useful information beyond promotional material.

Note to the mods:
I have no commercial interest in this. It's for information only.

 

[mwm1752]

another question please.

so when a light fixture says its rated for 60 watts, that means its rated for 60 watts of power. The safety factor tested on the fixture(so it doesn't create a fire) use up to a 60w rated lamp

what will happen when you put a 150 watt light bulb in the 60 watt fixture? You voilate the NRTL test and are at risk of damaging the fixture or surrounding structure.

I am asking because we do rework in which we find these light bulbs in the fixtures. Always replace with designed wattage - can't control what others have done.

The new high-efficacy bulbs are designed to have a lumens per watt greater than standard incandescents. They are generally found in flourescents & led type lamps. Laymans terms more light less energy used. There are several high-efficacy lamps that produce the same lumens that a 150w incandescent that draws less energy. Bottom line as long as the lamp you insert draws a max of 60w you have complied with the fixture listing.

 

[kwired]

Often you will find if a particular lamp is not intended for the luminaire it will not fit, or at least a cover will not be able to be reinstalled.

Sometimes that line is fuzzier between 60, 75 and 100 watts, but seems like newer luminaires have defined that line more so then older ones had. Then you have the disappearing of standard incandescents coming in play and will find even more different lamp types out there that do not let you install something not rated as it just will not fit - without modifications anyway.

 

[GoldDigger]

Took a look at an outdoor motion controlled light assembly a few days ago. The kind with one sensor and two lampholders wired to a round bell box cover.
Embossed into the lampholders was "Max bulb size 150W PAR 38." would you interpret that to mean that only PAR bulbs could be used under that instruction, regardless of size?
The assembly was rated for outdoor, wet conditions of course.

Tapatalk!

 

[cowboyjwc]

I have a light fixture under my desk that show's what happens when you put a 100 watt bulb in a fixture marked for 60 watt max. The family got lucky.