Revisions to UL Standard 943 Ground-Fault Circuit Interrupter (GFCI) Standard
As a result, they could have mistakenly assumed that the GFCI was functioning correctly and providing protection from electrocution. Furthermore, even if consumers did perform the tests, it was possible for an undetected failure or malfunction to occur between tests without an auto-monitoring system.
As a result, the following improvements will be made to GFCIs in order for them to meet the new UL Standard 943:
- Auto-Monitoring or Self-Test Function: This function allows for periodic, automatic testing of the ability of the GFCI to respond to a ground fault. If the Self-Test function detects a problem, the GFCI must deny power or provide visual and/or audible indication.
- Reverse Line-load Misfire Function - Repeated: If the line cable is wired to the load terminals of a receptacle GFCI, power to the receptacle face will be denied. This requirement applies to the initial installation and any subsequent re-installations.
In order for a GFCI to be certified by UL, it must meet many demanding requirements, such as:
- Detecting ground fault and interrupting circuit
- Corrosion resistance
- Drop and impact
To maintain UL 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.