Siemens plug in circuit breakers are intended for use in Siemens EQ, Siemens Ultimate, ITE, and Gould load centers or meter combinations. The single pole Siemens breakers may be used in single or 3-phase load centers and are 120V rated. To ensure the warranty on a Siemens panel is not voided, the use of Siemens breakers is required. 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.