Siemens QE130 30-Amp Single-Pole with GFCI Circuit Breaker 120VSiemens ground fault equipment protection circuit breakers provide protection of equipment from damaging line to ground fault current and de energizes the circuit for all ungrounded conductors of the circuit. Siemens strongly recommends against the use of "used" breakers. The installation of used breakers in a Siemens panel will void the warranty on the panel. Siemens does not sell used breakers and has not approved any 3rd party sellers to do so.