Electricians: any ideas what’s going on here?

Granite · Aug 8, 2026

I can’t figure out what’s going on with this home electrical/lighting issue … maybe you guys can!

I have a lighting circuit in my kitchen that includes a single switch (no dimmer) that runs 2 recessed cans in the ceiling. For 20+ years it has run incandescent R30 bulbs. In the past couple years I swapped to LED BR30s
Recently the LEDs started intermittently dimly flickering: first one, then they were fine, then the other (odd!). So I replaced one with an incandescent and they worked for the day. That night, with the switch off, the incandescent bulb burst. I found the shattered bulb glass on the floor in the morning. It didn’t explode all over far and wide; the shards just kind of fell straight down to the floor under the fixture.
More info:
- it’s been hot in the house; not our hottest, but pretty hot and muggy
- a multimeter on the switch says it’s working and voltage is between +\- 119.9 and 121.6 (is that a normal fluctuation?)
- no signs of heat in the fixtures
- dark streak in the bulb remnant
- the rest of the circuit is working normally

Any ideas?
I’m tempted to just replace the LED bulbs and go on with my life but it’s worrisome that this bulb burst with the switch OFF. Makes me wonder if there’s voltage leaking (voltmeter says there’s not) or maybe that thing just got wicked hot during the day and cracked at night when it cooled down? Why the LED flickering issue?

Thanks in advance for any advice! I’m trying not to burn my house down!

Here’s a pic of the bulb remnant to show the heat mark. I unscrewed this and laid it on the floor for the pic; it didn’t fall onto the floor!

Granite · Aug 8, 2026

I just noticed that these housings have 2 depth settings for the fixture: PAR and R; and they were on the PAR setting. Not sure if that matters …

B1Toad · Aug 8, 2026

The "R" means reflector so if the lamps have silver on the back they are reflector type and can recess further into the fixture as they reflect their heat downwards. My guess on the lamp breaking is maybe a defective lamp or it could have broke as it was cooling. I doubt it is an electrical issue, it sounds more like an overheating issue. See next paragraph, this is important.

Check those cans for the IC rating, if they are NON-IC rated there cannot be any thermal insulation within 3" of them, this is on the sides and the top. Trims that are not approved for a particular can may also cause heat issues. Most cans will have a list of approved trims.

Also when choosing lamps for recessed cans always get R, or Reflector lamps.

freedom_in_4low · Aug 8, 2026

Not an electrician, but certain LEDs in my house will flicker for 10 seconds at a time. It's only the ones on dimmers, but multiple bulbs on multiple dimmers (but not all bulbs that are on dimmers) flicker in unison. Others in my subdivision mention it from time to time, and though we've never checked to see if it's synchronized between houses, we've more or less just accepted that it's on the power company's end of things.

Your voltage measurement seems good to me. I've seen everything from low 110s to high 120s.

Granite · Aug 9, 2026

Helpful stuff, thanks guys!
@B1Toad I see “H5ICAT” (or maybe it’s “H51CAT”?) … do you think that is “IC”?

Granite · Aug 9, 2026

There’s also this sticker

Given the switch voltage test I’m fairly comfortable there is no leakage and that maybe the heat caused the LEDs to flicker and that plus a faulty incandescent bulb caused it to shatter. I also think one of these cans had the socket recessed to the farthest setting which would introduce more heat.

So I’m inclined to try it again and monitor the situation, shutting the breaker when we’re out of the house. Thanks guys!

Dr. Internet · Aug 9, 2026

First thing to check is ground. There should be a heavy copper wire from your main circuit panel connected to a ground rod, usually outside. Sometimes they break due to foundation movement. Also check to be sure it is connected to the ground bus bar inside your main panel. If you are not comfortable opening the panel, call an electrician. Turn off the main power before opening the box. Note that the main feeds (big fat wires, usually at the top are still energized, even if the main breaker is off.)
Next, check to see if your lighting circuit is connected to a ground fault circuit interrupter (GFCI) circuit breaker. It will be marked. They are known to cause problems with LEDs in certain circumstances.
Was there a storm that night? The brown spot near the base of the blown bulb is an indication of extreme heat, usually caused by a significant overvoltage condition. A lightning induced spike can exceed 20,000 volts. It would be unusual if one light bulb was the only thing affected. Everything else is OK (computers, microwave, TV)?
Are you close to an office building or a manufacturing plant? They can cause large voltage fluctuations, which can make LEDs flicker. They shouldn't cause an incandescent to blow, though.
If none of these work, you should contact a licensed electrician. There are other things that may cause your symptoms that an electrician can test.
Good luck!

B1Toad · Aug 9, 2026

Granite said:
Helpful stuff, thanks guys!
@B1Toad I see “H5ICAT” (or maybe it’s “H51CAT”?) … do you think that is “IC”?

View attachment 703598

Yep that's IC rated, and it's a decent can as well. It's of the age where all the recommended lamps are incandescent. If you are using LEDs you're probably good but still look for ones that are approved for enclosed fixtures as they handle heat better. Contrary to popular belief, LEDs get hot too.

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Electricians: any ideas what’s going on here?

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