In June 2012 UL learned of compatibility issues when Classified Fire-Resistive Cables were installed in systems where zinc was used as in interior coating in rigid steel conduits. At the high temperatures the zinc coating inside the conduit system vaporizes and interacts with the copper conductor creating a brass alloy. Brass melts at a lower temperature, which compromises the integrity of the electrical system causing premature failure. The UL-2196 test is designed to evaluate the performance of electrical circuit protective systems in severe fire events—specifically, when exposed to fire for 2 hours followed by the mechanical shock of a fire hose stream.
