Clearing the air on certification labels

I hired a licensed electrician to run power to my shed workshop. When the building inspector checked that work, he told me I couldn't use my air cleaner plugged into a ceiling outlet because it lacked Underwriters Laboratories (UL) approval. I returned that air cleaner to the store and searched for a replacement, but found that few air cleaners are UL-approved. Am I the only one to run into this?
—Ed Thompson, Matthews, N.C.

That's the first time we've heard of a building inspector disallowing a manufactured air cleaner, Ed. But you're right that most air cleaners lack certification from Underwriters Laboratories or any other testing service recognized by a majority of the state or local building codes modeled after the International Residential Code.

Different states have different requirements concerning the sale and use of noncertified electrical devices in home workshops, so the only sure way to know what's allowed where you live is to contact your local building department. In North Carolina, all electrical devices must be evaluated for safety by a qualified testing service recognized by the state. In addition to UL, those include the Canadian Standards Association (CSA) and Intertek Testing Services, which uses the ETL logo. Check for either logo, shown above, as well as the UL mark when shopping for equipment.

Bottom line: Your building inspector enforces that state law and has absolute authority to say what electrical devices can be installed. So while an uncertified air cleaner may still be safe, it may not be legal in your state.

If you're wondering why all equipment—not just air cleaners—doesn't carry some testing service logo, it's because product testing and certification can be expensive. One manufacturer estimates that initial testing and certification costs exceed $10,000 per product, not including annual certification maintenance costs. In a quick check of the stationary and benchtop machines in the WOOD® magazine workshop, two-thirds lacked any certification, and none carried a UL label.