Electrical Investigative Question

[Rich M.]

Helping out a friend rehab an old apartment building.

When doing a walk through, we found one apartment that was missing a wall switch receptacle and the dinning room chandelier. The wall switch controlled the chandelier.
According to the apartment manger the tenants installed a dimmer switch and when they turned the breaker on, flames started coming out of the lights on the chandelier. Not sure what happened to the dimmer or the chandelier.

I looked at the outlet wiring and the exposed wiring in the ceiling and everything looked fine.

Thoughts on how they could have installed the dimmer to cause a fire?

 

[PoorUB]

My guess it they got a bad dimmer and it failed on power up.

My dad had one that got so hot it melted the coverplate, but never caught fire. He won't have a dimmer in the house after that!

 

[ycgoat]

If the project is to fix it, I would not worry about verifying an old story. Ring out the wires and install the lights correctly

 

[Rich M.]

If the project is to fix it, I would not worry about verifying an old story. Ring out the wires and install the lights correctly

You are correct and that is the end game. This is a learning moment for me as I try to learn through everyone’s good and bad experiences to help prevent me in repeating someone else’s misstep(s). The whys and how’s of life.

 

[ycgoat]

Electricity is dangerous, Some possibilities are; If it was an LED fixture on a non LED dimmer, or a fan on a light duty dimmer, or a large incandescent fixture on an LED dimmer. They may have just wired it wrong such as using the white wire as a switch leg then connecting it to the neutral on a remote sensor, etc...

 

[tlmartin84]

Didn't something similar happen in Home Alone??? LOL

 

[Jim greengo]

I'd say an apartment building is not a good place to practice electrical work.
If something caught on fire up there in the past, it's time to open up the ceiling and check the wiring.

 

[dcg9381]

Thoughts on how they could have installed the dimmer to cause a fire?

My only guess would be 240v - they miswired with two hots.
That being said incandescent lights don't catch fire, they're enclosed in vacuum. So that's "sus" also.

 

[shoot summ]

Maybe a 3 way switch? If they popped the switch and added a dimmer, there is certainly a chance for some sparking.

 

[nadogail]

Without looking at the job, I can only guess that somebody goofed and the evidence is no longer at the scene.

 

[kaffine]

My guess would be the CFL or LED bulbs in use weren't compatible with the dimmer they were using.

 

[Rich M.]

This one has me stumped. For those that answered, it is a 120 15amp outlet and the chandelier had the candelabra style bulbs, not LED or CFL.

Wiring the switch from a regular to a dimmer should have been an easy task, so can a defective dimmer cause the chandelier sockets to catch fire?

I have never seen this happen so I am in the dark and the cause may never be known.

 

[ycgoat]

It could also have nothing to do with the dimmer and the light just shorted out from normal age and attrition.

 

[The Cobbler]

this story is based on the tennants version? anything is fair game with that .

 

[nadogail]

This one has me stumped. For those that answered, it is a 120 15amp outlet and the chandelier had the candelabra style bulbs, not LED or CFL.

Wiring the switch from a regular to a dimmer should have been an easy task, so can a defective dimmer cause the chandelier sockets to catch fire?

I have never seen this happen so I am in the dark and the cause may never be known.

I have LED candelabra type lamps in a fixture. They were a special order.

 

[Walkers]

I’d say misfired, cfl/led on a dimmer that wasn’t syp to be.

 

[FredWanaker]

who put in the chandelier?

 

[Wrench97]

Didn't something similar happen in Home Alone??? LOL

Na that was Tim the Toolman............................

 

[Rich M.]

who put in the chandelier?

Chandelier was the same as in every apartment, which was probably installed in the early 70’s

 

[cybrdyke]

I've seen LED lamps cause a dimmer to go up in smoke, but you have the opposite problem. If they were incandescent lamps in the chandelier, there's virtually nothing a dimmer can do to make them go up in flames. Even the worst mismatched dimmer would only result in problems like flickering or pulsing. You'd need significant over-voltage to make those lamps burn. A dimmer wont be able to do that.
CFL lamps or LED lamps can go up in flames all by themselves if they're defective. A mismatched dimmer could mess with an LED or CFL lamp bad enough to make it catastrophically fail.
If the chandelier definitely had incandescent lamps, then they probably experienced a loose or corroded wire at the socket, or some other issue that caused arcing.
CD

 

[SlappyWhite]

Do you have the chandelier itself. From the first post it sound like it was removed and the wires were hanging.

If so check it over. It could have been the cause. The insulation on the wiring could have been cooked from years of over wattage bulbs.

 

[Wrench97]

I've seen them hook up the switch drop in the ceiling fixture black to black and white to white.........................turn on switch to short.

 

[FredWanaker]

If they lifted the neutral from the light out of a group of neutrals, and attached it to one side of the dimmer and black (hot) to the other, and the fixture had smaller wires where the neutral was also bonded or shorted to the ground in the chandelier, the dimmer would have smoked and so would the wire at the chandelier. In this configuration the current would have gone thru the dimmer, thru the neutral wire, to the chandelier to ground.

 

[bwringer]

I've seen them hook up the switch drop in the ceiling fixture black to black and white to white.........................turn on switch to short.

My Mom's house was built by a dangerous ***** and was wired like this. Bits of car wire and old extension cords everywhere, not a ground in the place, and the plumbing was even worse.


As to the OP's question, I would do my best to completely ignore the story and focus on figuring out what you have and making things safe.

 

[MoonRise]

Commercial/industrial electrical typically REQUIRES a 'licensed electrician' to do all the electrical work.

In some locales, a homeowner and OCCUPANT of a single family residential dwelling is allowed to do electrical work, which still has to meet all applicable Codes and permits and inspections. Except for Chicago (and possibly some other locales), where a homeowner is not 'allowed' to ANY electrical work even in their own single family owner occupied residence.

But there is no owner/occupant 'allowance' to do electrical work for any commercial/industrial applications or for any multi-family dwelling (for instance, a two family home) or for a rental dwelling or an apartment.

That out of the way, without the failed parts to look at you would be trying to figure what may have gone wrong with no evidence to even look at.

Check all existing wiring and devices for their condition and for any signs of problems. Charring = bad, melted insulation = bad, soot or scorch marks = bad. That sort of thing.

 

[nadogail]

this story is based on the tennants version? anything is fair game with that .

When a Tenant tells me why or how something failed; all i believe is that their mouth works.

 

[Rich M.]

Commercial/industrial electrical typically REQUIRES a 'licensed electrician' to do all the electrical work.

In some locales, a homeowner and OCCUPANT of a single family residential dwelling is allowed to do electrical work, which still has to meet all applicable Codes and permits and inspections. Except for Chicago (and possibly some other locales), where a homeowner is not 'allowed' to ANY electrical work even in their own single family owner occupied residence.

But there is no owner/occupant 'allowance' to do electrical work for any commercial/industrial applications or for any multi-family dwelling (for instance, a two family home) or for a rental dwelling or an apartment.

That out of the way, without the failed parts to look at you would be trying to figure what may have gone wrong with no evidence to even look at.

Check all existing wiring and devices for their condition and for any signs of problems. Charring = bad, melted insulation = bad, soot or scorch marks = bad. That sort of thing.

Pretty much the same here as doing electric work. As for me, I am doing the grunt work and the electrician is checking everything I touch before he signs off. Nothing installed until he sees boxes, wires and fixtures.

 

[Chuckster in NJ]

Call a pro!

 

[Rich M.]

If they lifted the neutral from the light out of a group of neutrals, and attached it to one side of the dimmer and black (hot) to the other, and the fixture had smaller wires where the neutral was also bonded or shorted to the ground in the chandelier, the dimmer would have smoked and so would the wire at the chandelier. In this configuration the current would have gone thru the dimmer, thru the neutral wire, to the chandelier to ground.

I think you hit the nail on the head. Based on the limited information, I was thinking the same thing, just hoping someone posted to support my thought.