The Subtle Sign That Your Home Might Have A Dangerous Electrical Problem

Let's pretend for a moment that you don't check the temperature of your home's electrical receptacles and cover plates once a month. You might know you should because hot outlets are a warning sign of several electrical problems that can lead to house fires. Or you might not know about that, but who can remember such things anyway? Besides, what are the odds you'll even find all of the outlets?

Let's take a quick look at why you must check them from time to time — or at least know how to react if you happen across a hot outlet. In the case of a genuinely overheated receptacle, the cause is usually an excess of amperage moving through the outlet. This could be because you're using the wrong receptacle (say, a 15-amp receptacle for a 20-amp circuit), because you have things plugged in that are drawing too much current, or because you have a wiring problem like loose terminal connections. Though it's uncommon, overheating can also happen when a circuit is too long or has an overly long extension cord plugged into it. Electrical circuits should be derated in such circumstances; that is, the amperage allowed on the circuit is reduced when the electricity travels farther than a specified distance. Meanwhile, the voltage drop over a long extension cord can cause a device like an electric motor on the other end to attempt to draw more amperage than usual, creating even more heat.

That's all pretty scary. But sometimes outlets get warm, and it's usually perfectly normal and safe. How can you tell which situations are normal and which are dangerous?

Many ordinary circumstances can cause an electrical outlet to get noticeably warmer than the surrounding air. Plugging common AC/DC transformers like USB chargers and electronic gear's wall warts will do it, as will simply drawing a lot of power through the outlet over a long period. If something is plugged into an outlet and you find it warm to the touch, odds are everything is okay.

The rule of thumb is that if you find an outlet or its cover plate hot to the touch — that is, if you instinctively want to draw your hand away from it because of the heat — you should look into the cause immediately. You should also be on high alert if you see scorching or discoloration, notice burning smells or flickering lights, or find a circuit breaker tripping frequently. One concrete measure is what the pros use: The UL standard for determining if an outlet gets unacceptably hot is if it exceeds its normal temperature by more than 54 degrees Fahrenheit. This benchmark has been adopted by manufacturers for both receptacles and switches.

Of course, identifying that difference can be difficult. While you can teach yourself to feel a particular temperature, it would be easier and safer (and, honestly, more fun) to just periodically scan your walls with an inexpensive thermal camera like HSFTools' phone-attached Finder series or with a cheap infrared laser thermometer. The thermal imager route is your best bet, because it will also reveal many other potential problems, from wiring problems not tied to an outlet to water leaks to mouse nests.

However you determine it, if you have a seriously overheating receptacle, it might be time to call an electrician. But there are a few things you can do first. Try both unplugging everything from the outlet and plugging everything in more firmly. Remove extension cords and use fewer devices on the circuit if there's also an electric motor (like a fan) or an electric heater plugged into it. If the problem persists, turn off the circuit breaker, remove the outlet's cover plate, and inspect the receptacle, wallbox, and cover plate for damage. Check the terminals where wiring connects to the receptacle to make sure you don't have any loose connections (a serious DIY electrical mistake that can burn down your home) and make sure other connections are securely made with a wire nut or similar device. If tightening everything down doesn't immediately solve the problem, you might need an electrician's help.

While inspecting (and even replacing) an outlet is certainly something a homeowner can do, there are a number of situations in which it makes sense to get the help of a licensed electrician. Is your home's wiring or its circuit breaker panel many decades old? Are your outlets ungrounded? Do you need to have additional outlets, or even entire circuits, installed? Are there buzzing or crackling sounds in your breaker box or outlets you can't replace? Do breakers constantly trip mysteriously, or just fail to trip no matter what you plug into a circuit? Any of these is cause for alarm, and alarm is cause for a call to your friendly neighborhood electrician.