While browsing the website of a well-known Swedish furniture retailer, I found a clamp-on desk lamp I liked, which has a 13W power rating. To accompany this lamp, I would like to purchase a 1500lm 14W E27 LED bulb. Is it safe to put a 14W bulb into a lamp rated at 13W?

Even though the sites I visited in researching this issue didn't recommend exceeding a lamp's rated wattage, the given examples were along the lines of "don't put a 100W bulb into a 60W lamp". Since I would only be exceeding the rating by ~8%/1W I figure I'd still be well within the manufacturer's safety margin. Am I right?

Additional info: I am not planning to use the lamp in an enclosed space or near flammable objects. This is the lamp in question: https://www.ikea.com/ch/en/p/tertial-work-lamp-dark-grey-50355395/

  • 1
    a 13 W rating for the fixture is very odd .... is the bulb actually replaceable? ... please post a link to the lamp
    – jsotola
    Nov 1, 2020 at 2:05
  • @jsotola I added a link to the lamp in question and the bulb is definitely replaceable. Nov 1, 2020 at 2:25
  • 1
    @jsotola 13W is standard CFL size for "60W incandescent equivalent". They designed to that spec. They didn't test to destruction at 13W and 14W to determine that 13W was the max. Nov 1, 2020 at 2:27

3 Answers 3


It is never a good idea to exceed the ratings on a fixture. They are UL listed, in the USA, for the rating specified and that listing goes out the window when exceeded. The stickers I'm familiar with usually read something similar to: " WARNING! Do not exceed the listed rating". The ratings for LED fixtures are more critical because of the electronics in the fixtures. There are transformers, rectifiers, capacitors, etc.,that are very sensitive to overloads. Subjecting the components to an 8% overload could blow them out or greatly reduce their life expectancy. Do yourself a favor and get the right bulb.

  • 2
    I do not believe that the fixture contains any of the electronic components you just mentioned, since they would be part of the LED bulb. As far as I am aware, electrically, it only contains the E27 socket, the switch, the plug and wires in between. Nov 1, 2020 at 2:31
  • @SebastianHietsch You're right. That fixture is just plug, wire, switch and socket based on your edit. The basic idea remains the same... stick to the rated value.
    – JACK
    Nov 1, 2020 at 12:47

13W is not unusual at all. I have seen ratings like that ever since CFLs became popular. It is a typical equivalent (in terms of light output) to a 60W incandescent, and rating it for 13W allows for people to use the lamp in the "normal" way that similar "60W rated" lamps used to be used, provided they use a CFL or LED bulb.

My gut feeling is that when a fixture like that is designed, they figure out what kind of bulb will be needed (e.g., in the old days, 60W or 100W or 3-way 50/100/150; CFL era 13W for "60W equivalent"; etc.) and engineer to handle at least that amount of power & heat. In some cases, a "13W lamp" might be almost the same as a "60W lamp" and perfectly safe up to 40W, or even up to or past 60W! However, the testing is done only at the rating - i.e., test it with a 13W bulb.

The problem is, you have no way to know where/how the device is design limited. In addition to heat dissipation, there are other issues such as internal wiring that may be thinner (to save pennies, but that is a separate discussion) in the 13W lamp than in the 60W lamp. You have no way to know what the problems might be or how over-engineered vs. "just good enough" a particular lamp or other device is designed.

End result: Stick to the specs or get a different device.


No. No you can't. If it was ok for 14W, it would be rated for 14W, not 13W.

Of course, these ratings are always designed with some margin for error, and it's very possible you'd never have an issue.

But then again, the crap that that well know Swedish furniture store sells is all over the place in quality, I am not surprised when it fails when used as directed, so I would not be surprised at all if you cooked it with an extra watt. I'd be looking for a 10W bulb. You can get a lot of lumens for 10W these days.

  • 1
    If it was ok for 14W, it would be rated for 14W, not 13W. Not necessarily. I'd venture to guess that it is likely designed to handle at least 20W, probably more. But we have no way to know for sure and therefore "stick to the specs". Nov 1, 2020 at 14:56

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