In June 2012, UL learned of compatibility issues when Classified Fire-Resistive Cables were used in electrical circuit protective systems where zinc was used as in interior coating in steel conduits, raceways and other system components. Specifically, at high temperatures the zinc coating interacted with the copper conductor creating a brass alloy that melted at a lower temperature than the copper conductors alone, thereby affecting the integrity of the electrical system. The presence of zinc compromised the electrical circuit protective systems and caused them to not conform to UL2196.
April 6, 2022
Why the Electrical Industry is using Radix Duralife II Dual Rated CI/CIC Cable and Champion Fiberglass Type XW Phenolic Conduit for Two-Hour Fire Rated Fire
Alarm Installations
In June 2012, UL learned of compatibility issues when Classified Fire-Resistive Cables were used in electrical circuit protective systems where zinc was used as in interior coating in steel conduits, raceways and other system components. Specifically, at high temperatures the zinc coating interacted with the copper conductor creating a brass alloy that melted at a lower temperature than the copper conductors alone, thereby affecting the integrity of the electrical system. The presence of zinc compromised the electrical circuit protective systems and caused them to not conform to UL2196.