Siemens Q120DFN is a 1-pole, 120V AC, 20A dual-function circuit breaker with a plug-on neutral connection, designated UL Type QFGA2N. It combines AFCI (arc-fault) protection with a GFCI (ground-fault) function, delivering Class A 5 mA GFCI protection in a single device. Siemens notes that its dual-function breakers provide self-testing of both AFCI and GFCI protections, helping verify correct operation over time. The plug-on neutral design simplifies wiring and is intended for use in compatible Siemens load centers.
