It's disheartening that stores in the United States sell unsafe or uncertified products, but it does happen. Fortunately, there are organizations dedicated to keeping dangerous products out of your home.
Underwriters Laboratories (UL) and Factory Mutual are both certifying bodies that test products independently. They test electrical products (among others) to determine if they flame up when plugged in. If they don't, then these groups certify them, attaching a label to the products you can look for when you shop for electrical devices. In addition to looking for labels like these, Electrical Fire Safety Foundation International suggests that you steer clear of buying things like extension cords and circuit breakers from deep-discount stores. Also, look for name brands that you recognize and trust when buying products like these. Checking labels can also help. Look for spelling errors and bad grammar as sure signs that the product you're considering buying was produced by a disreputable company.
Back at home, take it easy on your home's power supply. It's not difficult to calculate the amount of power you're asking for from your outlets, and doing so can prevent a fire. Christmas lights are usually low wattage, coming in at about a combined total of 25 watts for 50 bulbs. If your circuit can handle up to 2,000 watts within the 80 percent amperage safety limit, you should be fine -- the brightness of so many bulbs would probably burn your eyes out before it would your electrical outlet. But other devices, like space heaters, use a lot more power than holiday lights. Simply unplugging one device when plugging in another can cut down on your risk of an electrical fire. And be sure to unplug all of your decorations before you go to bed.
It's also a good idea to take a good look at the wiring of devices that you're using this holiday season. Frayed or worn wiring is a red flag that you should replace the device it's attached to. The rubber insulation is meant to cut down on heat output and eliminate current arcing, and when it's missing, the risk of fire increases greatly. Also look for old plugs that don't fit snugly into an outlet. These can also cause sparking, which is bad when the outlet is next to a dead pine tree brimming with flammable sap.
Ultimately, you can't tell how many plugs are too many before an outlet will catch fire, except on a case-by-case basis. And it's not a good idea to conduct your own experiments at home. Instead, this holiday season it's a good idea to familiarize yourself with the electrical specifications of both your home and the electrical devices you plug into your outlets. Pay attention to the number of items you use on a single circuit, and perhaps leave the extra decorations in the attic this year. If not, those chestnuts in your kitchen may end up roasting on an open fire, whether you meant for them to or not.
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