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UL 943 GFCI standard being changed to address auto-monitoring

January 31, 2015 – The National Electrical Manufacturers Association (NEMA in the U.S.) along with Underwriters Laboratories announced changes to UL 943 Standard for Safety for Ground-Fault Circuit Interrupters (GFCIs)—a tri-national, harmonized UL 943/CSA C22.2 No. 144.1/ANCE NMX-J-520—that will take effect June 29, 2015.

To maintain certification, all manufacturers must meet these revisions with GFCIs produced after June 28, 2015. The current GFCIs bearing the UL Certification Mark can no longer be produced after June 28, 2015, but can be sold by manufacturers, retailers and distributors, and can be used by installers until their inventories are depleted.

The revisions to the tri-national standard were developed by a NEMA-led group in response to the U.S. Consumer Product Safety Commission (CPSC) requesting auto-monitoring requirements on GFCIs. The devices are supposed to be tested periodically, but end users weren’t doing that. Furthermore, even when the tests were performed, NEMA explains it was possible for an undetected failure or malfunction to occur between tests without a system of auto-monitoring.