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LED shop lights getting hot: normal or electrical issue?

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Forum topic by AM420 posted 06-18-2017 09:57 PM 401 views 0 times favorited 9 replies Add to Favorites Watch
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AM420

34 posts in 49 days


06-18-2017 09:57 PM

I just installed six 4’ LED shop lights in my garage. After they have been on for a while I noticed the metal housing was getting pretty hot. Not so hot that they burn my fingers but hot enough to make me worry. I assumed that since they’re LED they wouldn’t generate much or any heat at all.

A little info on the setup: I have two rows of lights from one light box. I spliced the wires from box to the first two lights on either side and then linked the rest together from the first fixture in each row. The fixtures have a ground, but the house wiring is old and doesn’t have a ground so I just cut it off on the future.

Thanks for any advice.


9 replies so far

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JBrow

1158 posts in 586 days


#1 posted 06-18-2017 10:45 PM

AM420,

I have some LED lighting experience as a consumer. I must say that there is a good part and bad part to my experience. Over the last three years I replaced most of the frequently used lights in the house and installed recessed LED lights for the workshop.

The good part of my experience is that I like the quality of light produced. I also believe that I have seen about a 10% reduction in the electric bill.

The bad part I suspect goes to your question about heat. Since a LED lamp is an electronic device, it generates heat like most other electronic devices. After having 5 of 11 LED recessed shop lamps fail and one kitchen LED lamp fail (at $30 each), I dug into LED lighting a little. Apparently one reason for failure is excess heat; heat in excess of what the lamp’s heat sink can dissipate. In short, too much heat, LED failure.

If your shop lights are in an enclosed housing with a diffusing cover, I might be a good idea to run the lights without the diffusing cover. Doing so should allow some of the heat you are now experiencing dissipate and potentially prolong the life of the lamps. Here a vendor article concerning LED lamp failureā€¦

https://www.shineretrofits.com/knowledge-base/lighting-learning-center/why-do-led-s-fail.html

Since it is fairly easy, reinstalling the fixture housing equipment grounding wire and connecting it to the circuit would ensure an added margin of safety.

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SignWave

388 posts in 2701 days


#2 posted 06-18-2017 10:53 PM

LED lights don’t radiate heat the way that incandescent bulbs do, but the electronics do produce some heat. If they are not in enclosed fixtures, then the heat should dissipate without any problem. Many screw-in LED bulbs will indicate that they are not suitable for enclosed fixtures, for this reason.

Are your lights mounted in a way that air can circulate around them? If so, I would not expect them to get so hot that you’d have a problem. I have some that are surface mount (touching the drywall ceiling) and some that are hanging on a short chain, both of which seems to be sufficient. The base of the fixture is a bit warm, but not dramatically so.

I don’t know if this helps or not… :)

-- Barry, http://BarrysWorkshop.com/

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MrUnix

5342 posts in 1865 days


#3 posted 06-18-2017 11:31 PM

LED’s get hot… real hot… particularly the newer high-output ones. If it were not for the heat sinks on the new-fangled bulbs, they would melt.

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

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AM420

34 posts in 49 days


#4 posted 06-19-2017 12:48 AM



LED lights don t radiate heat the way that incandescent bulbs do, but the electronics do produce some heat. If they are not in enclosed fixtures, then the heat should dissipate without any problem. Many screw-in LED bulbs will indicate that they are not suitable for enclosed fixtures, for this reason.

Are your lights mounted in a way that air can circulate around them? If so, I would not expect them to get so hot that you d have a problem. I have some that are surface mount (touching the drywall ceiling) and some that are hanging on a short chain, both of which seems to be sufficient. The base of the fixture is a bit warm, but not dramatically so.

I don t know if this helps or not… :)

- SignWave

I assumed they would get warm, but not as hot as they are. They are flush-mounted to the ceiling, so that may be making it difficult to dissipate the heat. They’re made to be flush-mounted, but I may try to find a way to let them separate a little with longer screws an shims. I can’t take the cover off. They’re sealed.

Hopefully these things last a while…

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htl

2652 posts in 825 days


#5 posted 06-19-2017 01:40 AM

Very interesting!!!

-- There's a hundred ways to do anything, alot depends on the tools at hand.

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woodbutcherbynight

3078 posts in 2075 days


#6 posted 06-20-2017 02:18 AM

For giggles measure the temp with a infared thermometer. The lights themselves should not be getting hot but the electronics that make the magic work do get hot. Since them make them cheap this is the part of LED’s that most often fails. The bulbs should last a long time, this they brag about. The electronics, not so much.

-- Live to tell the stories, they sound better that way.

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MrUnix

5342 posts in 1865 days


#7 posted 06-20-2017 02:43 AM

The lights themselves should not be getting hot but the electronics that make the magic work do get hot.

The heat is generated at the diodes N-P junction and then dissipated through the substrate, which is then attached to a heat sink to dissipate it further. The ‘electronics’ is nothing more than a power supply that reduces the AC line current into a small DC voltage. Most LED manufacturers specify a junction temperature not to exceed 125-150C (< ~300F). Put a bunch of them together, like in the current bulbs, and that is a lot of heat :)

Cheers,
Brad

-- Brad in FL - To be old and wise, you must first be young and stupid

View papadan's profile

papadan

2909 posts in 3034 days


#8 posted 06-20-2017 03:00 AM

I was in a Sams store today and looked at their 4’ LED shop lights. They have one on, in the display that has been on for almost 2 years non stop. The bulbs were cool and the top of the housing was just barely warm, no actual heat at all.

-- Artificial intelligence is no match for natural stupidity!

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woodbutcherbynight

3078 posts in 2075 days


#9 posted 06-20-2017 03:34 AM

My shop lights are retrofitted T-10 fluorescent fixtures that have no ballast and two LED light tubes in place of the T-10 bulbs. Both have all the electronics inside the bulb and having been on all day read 88F, shop temp at ceiling height was 80F.

Don’t have any of the newer LED only lights to compare with which is why I asked about the actual temperature. I have a attic fan in my eve that comes on at 80F. This keeps the air in the shop moving from the open window through the shop and out the vent. Turn that off and the temp where the lights are goes up with no airflow. This also could be part of your issue with heat. I recently added a window fan which helped airflow as it pushes the air toward the vent.

-- Live to tell the stories, they sound better that way.

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