Underground Feeder and Branch Circuit Cable. 600 Volt. Copper Conductors. Copper UF-B cable is generally used as feeder to outside post lamps, pumps, and other loads UF-B cable may be used for interior branch circuit wiring in residential or agricultural buildings at conductor temperatures not to exceed 90°C (with ampacity limited to that for 60°C conductors) Phase conductors are polyvinyl chloride (PVC) insulated, nylon jacketed, color coded for identification purposes. 100-Feet 12-Gauge 3-Copper Conductors Underground Feeder and Branch Circuit Cable, Gray