The next time you charge up your smartphone, take a look at the tiny symbols on the adapter. There are probably enough of them to make a NASCAR car jealous. And they all refer to specifications meant to keep you and your phone safe. After all, a lot can happen in electronic circuitry placed between you and a wall outlet, including fires.
Chances are you won't have to worry about such dramatic experiences if you're using the smartphone charger that came with your device or bought it from a well-known company such as Apple or Samsung. And there shouldn't be anything wrong in saving a buck by bringing home a lesser-known brand, provided it has the official markings of a safe product.
Two significant symbols to look for come from Underwriters Laboratories (UL) and Intertek (formerly Electrical Testing Laboratories, or ETL). Both are independent safety consulting and certification organizations affiliated with Nationally Recognized Testing Laboratory (NRTL) program of the Occupational Safety & Health Administration (OSHA).
These organizations have two core jobs. They check performance claims, such as whether a smartphone charger or other product outputs power at the promised voltage and amperage. More critically, they test electrical devices as well as the cables and accessories that feed them to make sure they comply with OSHA’s safety requirements.
“We attach tiny heat sensors called thermal couplers to significant points of resistance on the circuit board to make sure the product charger doesn’t overheat, [and] check the materials it’s made from to insure they’re sufficiently fire-resistant,” says John P. Drengenberg, UL’s consumer safety director. Testers also measure the thickness of the enclosure and other components to make sure nothing would prevent the product from being used properly, possibly adding a fire danger.
The symbol for UL is a circle with a misaligned “U” and L” inside it (see above). For Intertek, it’s the initial of the company's old name, ETL, surrounded by a circle. Both groups keep a vigilant lookout for counterfeiting and logo placement. Occasionally, a logo might seem to imply that an entire product has been certified, when in fact the label applies to just one component, such as the battery. (Such potential confusion led to a conflict between UL and hoverboard makers this past winter.)
One difference between the two organizations is that UL also develops testing standards, while ETL follows those standards along with standards established by other organizations.
Other Symbols
CE. This stands for the French phrase "Conformité Européene" which means "European Conformity." This logo, which is found on products that might be sold in the approximately 30 countries participating in the European Union marketplace, is not so much a certification as a declaration by the manufacturer that the product meets relevant European health, safety, and environmental protection legislation, as spelled out in each country’s Product Directives. Having that symbol allows a product to be sold with less red tape within the EU.