Outback PNL-GFDI-80 front panel mount GFI with stud terminals on the back. One 0.5 amp breaker ganged with one 80 amp breaker with common trip. 1/4" stud ring terminals required. This GFDI breaker uses two of the standard .75" breaker slots in the enclosure. Ground fault protection is required by the NEC for PV arrays mounted on or within a specified vicinity of residential dwelling roofs as a safety precaution. The OutBack PV Ground Fault Protection System protects wiring and system components for one or two PV arrays when used in a FLEXware 250, FLEXware 500 or FLEXware 1000.