UL, ETL & Listed Equipment

A UL, ETL or CSA mark on a cord, heater, light or tool means an independent lab tested a sample for safety. OSHA’s electrical rules rely on these listings, and cheap unlisted equipment bought online is a common source of shocks and fires.

• All workers
• Electricians
• Purchasing

What the marks mean

• OSHA recognizes certain labs as Nationally Recognized Testing Laboratories (NRTLs), such as UL, Intertek (ETL), CSA Group and others.
• A listed product has been tested to a safety standard and is subject to ongoing factory checks.
• OSHA generally considers electrical equipment acceptable when it’s listed or labeled by an NRTL for its use.
• “UL Recognized” components are parts meant to go inside other products, not complete products.

Use it the way it was listed

• Follow the label: indoor or outdoor, wet or dry location, and maximum load.
• Don’t modify listed equipment, like cutting off ground pins or replacing cords with lighter ones.
• Use extension cords rated for hard or extra-hard use on construction sites. See Extension Cords.
• Use heaters and lights listed for the location. See Temporary Heaters.

Red flags

• No listing mark, or only a “CE” mark (a self-declaration for Europe, not a U.S. safety listing)
• Blurry, misspelled or sticker-only marks
• Very cheap electrical products from unknown online sellers
• Cords that feel unusually thin or light for their rating

Many labs offer online directories where you can check a listing by company or file number. See also Spotting Counterfeit PPE.

Last updated: October 2, 2026