How do I know if this outlet is safe to use?
May 5, 2020 1:33 PM   Subscribe

Upstairs neighbors did something that resulted in a little water dripping from my ceiling. It appears to have gotten behind a wall outlet as well, and I’m now concerned as to whether it’s safe to use.

The outlet had a surge protector plugged in at the time of the water exposure, which I unplugged after I heard buzzing coming from the outlet. Since the outlet kept buzzing, I cut off all electricity to half of my home via the circuit breaker for about a day (the building is old, so multiple rooms - kitchen, bathroom, and 2 extra are all on the same 20 amp breaker). There has been no buzzing since I turned the breaker back on.

After a cursory observation my super stated I could use the outlet again after 36 hours, which I extended to around 60 to be safe. When I started plugging in the surge protector, however, I saw a blue spark; this freaked me out enough that I decided to leave it unplugged.

1. Given the above, is there reason to believe the outlet is currently safe to use/will be safe to use in the near future?
2. If not, what are my next steps? Request that my super/landlord send in an electrician?
3. (Slightly unrelated) Is it possible to change the configuration of rooms to circuit breakers? I don’t want to have to shut off half my home again if there’s a problem in only one room, and I appear to have a spare 20 amp that isn’t connected to anything. The super said it wasn’t possible as it would require new wiring to be placed in the walls, etc. but I don’t know how knowledgeable they are on the electrical front.

posted by Sakura3210 to Home & Garden (12 answers total) 1 user marked this as a favorite
According to the National Fire Protection Association's Electrical fires safety tip sheet, in the IMPORTANT REMINDER section, you should "call a qualified electrician or your landlord if you have: [...] Sparks from an outlet."
posted by katra at 2:57 PM on May 5, 2020 [1 favorite]

A quick blue spark -can- be normal when you plug something in. Yellow sparks in the absence of something plugged in are a major danger signal, in contrast. Burn marks are also signs of a bigger problem.

The major danger here is if remaining water is causing a short between elements or exposed connectors behind the wall. In theory, it should take a fair amount of water for that to happen, as exposed connectors aren't exposed for much distance. In theory, your circuit breaker should trip and protect you in that case.

If everything else is dry, you could try plugging in something simple like a lamp.

LL is almost certainly correct that using the spare 20A circuit would require a fair bit of work by an electrician, in most cases.
posted by Dashy at 3:58 PM on May 5, 2020 [1 favorite]

Anything that is turned on when you plug it in will almost always result in a (tiny and contained within the outlet, but visible/audible) spark. Switches are designed to switch current, plugs are not. If it was enough to cast a blue glow and make more than a tiny snapping noise about as loud as the rocker switch on the surge protector or discolor the outlet or the plug, you are right not to use it.

After that length of time, I'd have no worries about the water absent some other symptom. I'd be much more worried about the ongoing fire hazard of having a 20 amp circuit feeding (many!) sockets and fixtures rated for only 15 amps. That it runs half the dwelling makes it even more bothersome, as it is all too easy to inadvertently overload the circuit and trip the breaker repeatedly, which will eventually result in it not tripping when it needs to.

Even my shoddy 1930 vintage duplex that had knob and tube wiring still in service had a separate circuit for the kitchen.

All that said, it would not be at all unreasonable to ask for the socket to be replaced. They are cheap and only take a few minutes to install. Either way, you need to be very cognizant of what you're powering from that circuit. Also make sure you have an appropriate amount of renters insurance and that your smoke alarms are in good working order. You probably won't have a fire, but I wouldn't bet against it, either.
posted by wierdo at 4:41 PM on May 5, 2020

According to what I saw in a recent rerun of This Old House, there is fairly cheap gizmo you can buy at the hardware store for $10 or less which can tell you if there any kind of short circuit or if the outlet is not properly grounded. I have no personal experience with such a thing.
posted by SemiSalt at 4:51 PM on May 5, 2020

Just for some clarification on points made above and in the original question:
-The thing SemiSalt is talking about can determine if the wires were installed incorrectly in the first place, but would not be useful for this setting.
-You landlord wasn't bullshitting when he said it'd be a bitch to re-wire. Just because you have a space in the fuse/breaker panel doesn't mean you can just port certain elements of the circuits over to the blank space. Wiring is done with the least connections in the breaker panel. Each outlet, switch/light pair, etc is linked in a series, with only one run home to the panel. So taking all of one room's devices would involve re-wiring the circuit to all of those devices individually.
posted by notsnot at 5:44 PM on May 5, 2020

If the breaker at the main panel isn't tripping, it's fine.
posted by humboldt32 at 6:18 PM on May 5, 2020

On the off chance you might have a newer outlet with built-in USB: Those could be more dangerous in this situation. There's active electonics in such an outlet that could catch fire.

I'm mentioning this mostly because of the buzzing you heard, which seems more likely to be a failing voltage converter in a USB outlet than a short in a standard outlet.
posted by joeyh at 8:48 AM on May 6, 2020 [1 favorite]

The outlet consists of just one three-prong plug-in and a switch (controls the room’s overhead lighting). Having waited another day, I decided to try plugging the strip in again; I got yet another blue spark, this time accompanied with a loud “pop.” At this point, it seems like it’d be best to ask for a socket replacement, especially since that outlet is what I’ve been connecting my entertainment system to. Is it possible that the water may have damaged the wall wiring also?
posted by Sakura3210 at 7:28 PM on May 6, 2020

The wall wiring will almost certainly be as OK as it ever was. At worst a couple of inches would have to be cut off the end. It does sound like the socket is forked. Loud popping and sparks you don't have to be specifically looking for to see indicates serious damage to the blades, either from corrosion or the arcing itself.

Be sure to check the prongs of the things you've plugged into it for discoloration, pitting, or other damage.
posted by wierdo at 8:47 PM on May 6, 2020

Super didn’t listen to me and decided to “test” the socket by plugging and unplugging my surge protector repeatedly - more popping occurred, and now one of the prongs on the protector looks singed (tip is black, and the metal feels corroded).

Should I assume the protector will need to be replaced? Also, do I need to be concerned about the electronics that were plugged in? I’d test it if I could, but there are no other available outlets and the busted one apparently won’t be repaired for a number of days.
posted by Sakura3210 at 8:57 AM on May 7, 2020

Your stuff is probably fine, but do replace the surge protector or there's a good chance the poor connection will destroy the new outlet in short order.
posted by wierdo at 10:53 AM on May 7, 2020

Thanks so much, will do!
posted by Sakura3210 at 8:00 PM on May 7, 2020

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