Are wall sockets designed to only deliver electricity up to their designed maximum - with some sort of safety shutoff - or do they just deliver as much power as a user demands, regardless of consequence?
If someone does plug too many (or too powerful) devices into a wall socket at once, does it cause overheating + fire more or less within minutes or seconds, or does it take hours/days/weeks?
The circuit breaker is designed to trip when too much power is drawn from a receptacle.
I have seen wall plugs get warm. Usually older receptacles that are worn out and need replacing.
A loose plug in a receptacle creates resistance and that can be dangerous. It can over heat quickly.
Most wall outlets are rated for 15 amps. If you let the smoke out of the outlet, the circuit breaker should trip.
How old is the location?
30 years old, I think.
There’s a noticeable smoke odor which I suspect might be from plugging too many appliances into one socket’s wall power last night, but - there was no smoke smell during the 6-7 hours yesterday when it was all plugged in, only this morning. So it doesn’t make sense that the wall socket would have tolerated an overload for that long yesterday.
The safety device is the circuit breaker. If you have an outlet rated for 15 amps, and you connect it to a 15A circuit breaker with 14-gauge wire, it should be able to move 15 amps of current without any undue hazard.
It depends how much current draw we’re talking about. If it’s a hair over 15A, and your outlet is healthy with good solid connections to the wiring, it might just get a little warmer than usual. If it’s way over 15A (on a 15A outlet wired with 14-gauge wire), and you’ve got a defective circuit breaker, the equilibrium temperature could be hot enough to cause problems.
As noted, loose connections have higher electrical resistance and can create hot spots. This includes outlets that don’t grip the prongs of your plug tightly, and it also includes loose connections to the wiring on the back of the outlet - either because the terminal screws loosened up over the years, or they were never properly tightened to begin with, or because they used backstab connections. If your house is 30+ years old, there’s a chance the outlets might have back-stab connections.
How many and what type of appliances did you have plugged into this outlet? Heat-generating appliances (microwave ovens, space heaters, etc.) move a lot of electrical current, but you could plug in a dozen phone chargers without any concern at all.
Note:
“smoke smell” is alarming. You’ve got a bad connection at the outlet that’s overheating. A 13 amp load through a loose connection will never trip the 15 amp circuit breaker*, but can overheat enough to cause a fire.
The $64,000 question: Do you have Aluminum wiring?
I would kill the power and pull the receptacle to check for burned wires.
Go ahead and replace the the 30 year old receptacle. Don’t buy the cheap 75 cent bulk crap at HD. They also sell Leviton in a box for 2.25. Much better quality.
Remove one wire at a time and place under the same screw on the new receptacle. That way you get the wires back correctly.
Call an electrician if you aren’t comfortable with DIY.
This is a very simple 15 min job.
I have no idea.
@ the others: Thanks for the feedback and input, I will see if such is the issue (thankfully, due to being in an apartment, I could get maintenance to check)
An AFCI will not necessarily sense a bad connection for a couple reasons:
A “bad connection” could be defined as simply too much contact resistance. Which could heat up and cause a fire. Arcing sometimes accompanies a bad connection, but you can still have a high-resistance connection with no arcing.
AFCIs are pretty good at catching parallel arcs. But a bad connection that is arcing is a classified as a series arc, which are much more difficult to detect. The newer “combination” AFCIs supposedly catch series arcing along with parallel arcing, but I’m a bit dubious at how effective they are. Would like to read some test reports.
At any rate, the OP needs to replace this outlet ASAP, and inspect the others. Immediately replace any that have “back stab” connections.
He said the house is 30 years old. If so, I’m pretty sure the wiring would be copper and not aluminum.
But… if the wiring is aluminum, and if the house was actually built in the 1960s or 1970s, he has a problem on his hands.
Wall outlets will tolerate overloads for years, then fail rapidly: the process of failure accelerates at the end.
Fires started by electrical failure can smoulder quietly for hours, then start to smoke, then burst into flames: the process accelerates at the end. Or they can just go out, harmlessly.
When I worked for a fire-detection company, electrical faults were an extremely common cause of office fires — because offices don’t have kitchens or garages, which cause most home fires. Don’t overload your sockets.
You really should endeavor to find and eliminate the source of the “smoke smell”.
If you let the smoke out electrics don’t work properly.
A 30yo house was built in the 90s.
you’ve been getting a lot of smoke smell in your apartment lately. are these for sure isolated events, or are they related in any way?
and regarding breakers and their ability to respond to overloads, there are some brands/ types of breakers and panels that have proven dangerous over time because of their inability to correctly respond to overload situations.
zinsco breakers and fpe stab-lok breakers are the ones I’m talking about.
they have been very problematic (fire hazards due to not tripping when they should) and should always have their panels either updated or replaced as soon as is reasonably possible.
despite their problems having been known about for years, I still run into these panels in homes frequently.
I had a similar problem but couldn’t pinpoint the exact receptacle where the smell originated. I just started replacing them one by one and as someone else mentioned I used the commercial receptacles that went for a couple bucks instead of the 75 cent ones. My house was wired in the early 80s and they had used the push in connections on the back. When I replaced all of them I did not go back that way. I curled them around the screws. When I found the one that was giving the problem you could see where it had overheated so much it made the cheap receptacle brittle and had actually burned the insulation back a little on the whites. I cut and stripped that off before putting the new receptacle in. You can buy boxes of 10 of those commercial ones that make it cheaper. I’d replace all of them in that room. It’s what I did anyway.
It is possible to wire a branch of outlets in a way that the hot spot is not at the outlet with a high load attached. So check that all the outlet wire connections are tight and free of corrosion. If the wires are silver colored, then it is aluminum wiring. Redo all connections with the proper grease that is needed for aluminum connections.
backstabbing receps is the worst. how it’s still a code compliant option (even though they’re only available for 14g wire, which most recep circuits aren’t wired with), I’m not sure.
daisy chaining (passing thru a receptacles tab screw to screw) is considered poor practice.
receps should be pig tailed and tied into it’s circuit.