5

My bathroom has three MR16 light fixtures in the ceiling, all with LED bulbs.

One of the fixtures sometimes fails to light up so I have to flick the switch back and forth until all of them light up.

I can tell that the problem is the fixture and not the bulb because the problem persists even if I swap the bulbs.

Is there a fire risk if I leave the power on for an extended length of time without the LED lighted? I habitually make sure that they all light up, but I know that some devices can be dangerous if not functioning properly like fans (due to stuck bearings).

Improve this question
2
  • Aside - when you change lamps are you fitting another of the same brand? Could be all of that brand (or that box) are slightly undersized. Try swapping a known working lamp in from another fitting but rememeber they get hot.
    – Criggie
    Commented Jul 29 at 12:52
  • does your LED fixture have bearings?
    – ron
    Commented Jul 29 at 14:19

4 Answers 4

Reset to default
8

There isn't any inherent danger of having a bulb that doesn't light up in a light socket. Not only that I have never heard of LEDs exploding or catching on fire and there are no dangerous materials in them. It sounds like you have one of four issues - I will try to list these by probability.

  1. The switch is incompatible with LEDs - or your specific LED bulb. What you are sharing happens often with normal dimmable switches that were never intended for LEDs. Also most mr16 fixtures originally had halogen bulbs - you could test your fixture/switch with them if you have extra laying around.

  2. The contact plate on the light fixture isn't hitting the bulb right.

  3. The switch needs its dimming sensitivity adjusted.

  4. Sometimes it is the fixture. I haven't seen this a lot but an arm of the fixture could have issues. It wouldn't make sense that it is an LED compatibility issue but who knows (the mr16 LEDs could have slightly different contact feet than halogen or even different brands).

Improve this answer
7

"Is there a fire risk if I leave the power on for an extended length of time without the LED lighted?"

No, its actually the other way around. If there is an intermittent contact, it is probably also a poor contact, ie a small spot of high resistance, which could overheat when current is flowing. (So the risk is not there if the bulb is not lit.)

Improve this answer
2

Probably not a safety issue, assuming it's an approved fixture to begin with. While a bad connection, especially with a relatively high current, can cause overheated connections, your "switching on and off" indicates something else is going on. (Note that overheated socket contacts in themselves should not be a safety issue because of the fixture design to get approval, and in any case you're not seeing that).

If you have replaced 12V halogen MR16 bulbs with LED bulbs the electronic "transformer" may not like the LED load. Sometimes having one halogen bulb and the rest LED can work. Changing the bulb type can help too. I've done both with an over-desk fixture I have, and it's currently working fairly reliably with 3 LED bulbs and no halogen though it does flicker a bit from time to time.

Or just replace the entire fixture with an LED type.

Improve this answer
1

Probably not dangerous with if the light doesn't power on. Fans are dangerous if turned on when not working because they have an electric motor, whose internal resistance depends on the amount of work the motor is performing. If the electric motor isn't preforming work (IE the fan blade isn't spinning) its resistance goes to 0 and it starts heating up due to an excessively high current flow. This leads to fire.

Light bulbs work in a different way. They don't have electric motors.. But instead are solid state devices that basically convert electricity into light/heat, very efficiently.

If they aren't working its because current isn't flowing thru them. So a lightbulb that doesn't work isn't dangerous (current flow -> heat -> fire, no current no heat, no fire). What is dangerous however is a fixture that isn't working.

Caveat This assumes that voltage applied is not higher than the lightbulb was designed for. Incandescent bulbs which convert electricity into light very inefficiently can get extremely hot, and start fires. LEDs will explode if too much current is applied (I haven't seen that cause a fire, its not much of an explosion, but it could happen). Fluorescent, halogen, etc.. can get pretty hot as well.

You have a bad fixture.

One of the fixtures sometimes fails to light up so I have to flick the switch back and forth until all of them light up.

This is concerning. Out of curiosity can you smell any ozone in the room?

Your fixture most likely has a loose wire that sometimes comes in contact and/or arcs allowing the lightbulb to turn on. This is bad as arcs can start electrical fires, but as long as all your wires are inside of an electrical box the chance of one starting is low.

How do I fix this

Open up your problem fixture, check all of the wire nuts and replace the one that is partially melted/charred. Taking extra care to tighten it properly.

"Loose wires cause fires."

Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.