What Is UL Listed and Why Does It Matter?

If you’ve plugged in an extension cord, swapped out a light fixture or made a piece of toast, you’ve likely used a UL-listed product. You may have noticed the small UL mark printed on the label or stamped on the product itself.

UL stands for Underwriters Laboratories. For more than 100 years this organization has been developing safety standards, testing products for compliance and putting its mark on things we use every day. Now called UL, it’s one of the largest and best known safety certification organizations in the world.

What Is UL Listed?

UL listed means UL has certified a product will safely perform its job as intended. Products earn that certification by undergoing rigorous testing against standards developed by UL. These standards are designed to be acceptable to code enforcement authorities, like inspectors.

When you buy outdoor lighting for your front porch, you expect the lights will illuminate your entry without giving you an electrical shock, right? You presume the lights were checked for safe operation before they made it into your shopping cart. That’s what it means to be UL listed.

UL certification is voluntary for manufacturers. But government agencies like the Occupational Safety and Health Administration (OSHA), and code standards like the National Electric Code (NEC), require listed products for many installations.

Nonmetallic-sheathed cable, commonly used in residential wiring, is required by the NEC to be listed. If you remodel your home and choose an unlisted cable, the electrical inspector will not approve the project.

UL isn’t the only company approved to test and certify products, but it’s the most well-known. UL, Intertek, Eurofins and 18 other companies are currently approved to test and certify products under OSHA’s Nationally Recognized Testing Program. Code authorities know labs on OSHA’s list are reputable certification organizations.

What Products Can Be UL Listed?

Appliances, electronics and electrical components, motors, batteries, smoke alarms and automotive parts can be UL listed. Gas meters, containers for flammable liquids, lighting of all kinds and door hardware can be UL listed, too. So many things can be listed that UL created a searchable database to take away the guesswork.

Electrical and fire safety, as well as prevention of injury, are huge drivers of UL’s certification process. That’s reflected in the more than 1,500 standards currently available.

Plenty of things you might not think of as hazardous can be listed, too. Makeup and personal care products, packaging materials and even furniture can be listed.

UL will certify manufacturing processes, entire facilities and personnel. As technology becomes more advanced and consumers and lawmakers demand higher energy efficiency and sustainability, UL listing capability expands to meet the needs of the times.

Does UL Listing Matter?

Absolutely.

Consider two sets of outdoor cantina lights for your backyard deck, one listed and one not. The UL-listed set is certified for year-round outdoor suitability and electrical safety, and the cord has enhanced flex and strain relief components. The other might be a perfectly capable string of lights, but how would you know?

A UL mark is a quick way for consumers to determine a product was manufactured to a high safety standard. If you have a choice, go with the listed product every time.

UL listing also matters for DIY projects around your home. Remember, the NEC and other code bodies require certain installations and products be listed to be code compliant.

Before starting any project, particularly electrical, read and understand the relevant code for your project or consult with a licensed tradesperson. Buy approved products and follow the instructions included with the product. UL listing doesn’t cover “off-label” installations.

What if you’ve done your due diligence and installed the UL listed cantina lights, but you come home to a melted mess at the end of the cord?

First, turn off the electricity before unplugging it, then tell UL. They’ll investigate the lights, follow up with the manufacturer if needed, and possibly put out a public notice. Always report suspected faulty products or counterfeit UL listings.

UL Listed vs. UL Recognized

• UL Listed: This mark refers to the entire standalone item, whether it’s a simple metal outlet box or a front-loading high-efficiency washing machine. The marks on these two products might look slightly different — the washing machine could have an energy efficiency notation on the mark, for example — but they will both be listed as a complete product.
• UL Recognized: This mark is used for components of products, not the finished product itself. The front-loading washing machine will have multiple UL-recognized parts, such as circuit boards, switches and an internal power supply. Each of those could also be made up of multiple recognized components.