5SJ4 Miniature Circuit Breakers Siemens 5SJ4 Miniature Circuit Breakers come in 1-, 2- or 3-pole versions with 0.3A to 63A rated current. These 70mm mounting depth devices are smaller than traditional molded-case circuit breakers and feature identical wire screw connections on the line and load sides. Siemens 5SJ4 provides DIN rail mounting, an ON and OFF/Trip visible indicator, and EN50274 touch protection.