The Siemens SENTRON 5SJ6125-6 is a 1-pole miniature circuit breaker rated at 25 A with a B-curve tripping characteristic, designed for 240 V AC circuits and delivering 6 kA breaking capacity per EN 60898 and IEC 60947-2.
If your site has transformer-fed sub-distribution with higher fault current, this MCB won't coordinate; you'd step up to a 10 kA or 15 kA rated unit. The 25 A rating at 240 V AC covers common lighting, socket-outlet, and small-appliance circuits on a single phase. At DC, the maximum rated voltage is 60 V — so it works for 48 V telecom or control power supplies but not for a 110 V DC bus. Wire range accepts 0.75 to 25 mm² solid or stranded — covers everything from 1.5 mm² lighting tails up to 6 mm² feeder circuits in a single terminal. The terminals are touch-protected (IP20 with conductors connected), and the unit is sealable for anti-tamper applications.
Ambient temperature range is -20 to +45 °C, with periodic excursions to +55 °C and 95% humidity; storage range is -40 to +75 °C. Vibration resistance tested to 50 m/s² at 25-150 Hz and 60 m/s² at 10-150 Hz per IEC 60068-2-6, so it holds up on machine-mounted sub-panels. Overvoltage category 3 means it's rated for fixed-installation distribution boards, not for equipment-level protection. The mechanical service life is 20,000 switching cycles typical — adequate for a distribution MCB that sees infrequent manual operation, not for a switching duty cycle. Compliance documentation includes the usual Siemens declarations: RoHS, REACH, and CE marking per the Low Voltage Directive; UL and CSA listings are not cited on this entry, so verify with the factory if your spec requires them.