Hi, I'm waiting for an electrician but thought I'd check your thoughts.

While watching TV last night our kitchen lights (which were all off) suddenly came on, went off, came on again. Couldn't turn them off, and then there was smoke and fire at the switch. We shut off the circuit at the breaker box and called the fire dept. No fire was traced through the walls, thankfully. Everything seemed contained within the switch.

House was built in the 90s. We are newer occupants. The switch is near the sink over the dishwasher. It ran earlier but is on its own circuit; could steam from it have caused a problem? Other things are on the same circuit -- we're evaluating "how much" but it doesn't seem like too much.

The switch has a dimmer, slider switch on it. We NEVER use it because I don't trust them.... several are throughout the house but we don't use the dimmer feature.

The burned switch operates 3 hanging fixtures over the counter, and 1 recessed fixture over the sink. Wattage of recessed fixture is 65W, each hanging fixture is 50W (all incandescent). Switch says 500W for both sides used, and 400W for one side used.

Looking at the burned fixture, no wires are melted and no evidence of fire inside the housing. There are 3 wires: brown, white and black. The actual switches are melted in place in the off position. We use metal cover plates.

Any ideas about what caused this to happen? Wondering about the other light/dimmer switches throughout the house, and maybe they should be replaced. Not feeling too comfortable about going away for even a weekend in light of this

Thanks for reading!
Belinda

 

Poor connection, including a short to ground? Actually, no, not without being able to see the switch, box and wiring.

What make and model is the switch?

FWIW, I've installed dozens, if not hundreds, of dimmer switches over the years, and I've never even heard of a problem like this before.

 

Thanks for your comment -- Leave it to us, we always seem to end up with unexplained problems here. Ghosts.....

I will have to get it from the trash for numbers, and I'll post later. But it's a Lutron. The electrician can't say exactly what happened either. Says it was definitely the slider. The wires are all in perfect shape. Says maybe some vibration caused arcing and it just got too hot. We are thinking about arc fault protectors in certain places, but there are positives and negatives about them.
B.

 

I'm going to guess the triac shorted to the grounded heatsink.

 

If you still have the dimmer, you may want to consider sending it back to the manufacturer. At the least, they may send you a new one. Otherwise, it may help them in determining what happened and ensure it doesn't happen again.

 

That says a lot.

And the negatives are? Arc fault protection is now required, for good reason, in any area where someone might be asleep.

 

Zorfdt:

Thought about that. It's a good idea.

 

The use of arc fault has been expanded to most areas in the house now. The common exceptions are GFI protected areas, fixed in place appliances and 240 volt equipment.

 

Nashkat1:

Only numbers I see are on the face below the switch: AY - 600P and 0109144269001. The rest are patent numbers, etc.

If you want pictures, I can try to upload a few in the next few days.

As far as Arc fault protection, the only real negative we learned about was the possibility of tripping the circuit breaker too frequently. But, after this scare we are putting some in anyway.

We're having a whole-house preventative check, and we will replace the sliding dimmer switches, even though lots of people use the very same ones (even the firemen). You can't prevent every bad thing from happening, but after this I'm almost ready to live by flashlights

 

Thanks pcboss -- we have GFI outlets in proper locations around the house (kitchen, bathrooms) for appliances. We have to determine what gets arc fault protection. One good thing that came out of this is that we now have a great electrician. I have confidence he will help us.

 

ok, you addressed the burnt switch, but what about the burnt light fixture. You said:

What are you doing about the burned light fixture?

 

I'm sorry CasualJoe -- I didn't use the right word. When I talked about fixture I was referring to the switch itself. Nothing else was burned-- no light fixtures -- just the switch.

I'm sending the switch back to the company. They want it. They have not heard of this happening, so they will have their quality assurance people examine it.

 

Thankfully you were home at the time and were able to handle the situation by turning off the power. By the way, there are almost 68,000 home electrical fires a year. Since you involved the fire department, you are now a statistic, but a lucky one.

You do own the home, right? You are not a renter I assume.

 

Sorry to not get back sooner. Yes, we own and were extremely fortunate to be home. I will try to post some photos of the switch.

Electrician examined every switch in the house to be sure things are properly wired. All is well.

The manufacturer responded after examining the switch determined that the problem was ANTS. That's right....they found a few tiny ants with a magnifier. Fried, of course. We had an infestation in early spring, saw some coming in around that switch and a nearby outlet. Had a problem getting rid of them.

They believe the ants caused a shortcircuit. The $64 question is: were they "old" ants that died from extermination or "new" ants trying again. No one will ever know. Exterminator says he's 99.9% sure there are no new ones now because we are in winter months here. But, before the fire, we has very warm weather and ants were still out.

Fire Chief says he has been around a long time but never heard of ants causing such a thing.

 

Thanks for the update. Very interesting.

 

Maybe he hasn't been around as long as he thinks if he's never heard of Fire Ants.

 

Just toooooooooo funny!