The Siemens 3VA2125-8JP46-0AA0 is a SENTRON molded case circuit breaker (MCCB) configured for line protection, carrying a 25 A rated continuous current (Iu) that holds across the full operating temperature range from -40 °C to 70 °C — no derating needed even at the 70 °C ceiling. The 4-pole frame and ETU550 electronic trip unit give you adjustable long-time delay (0.5 to 25 s) and N-conductor protection configurable from OFF to 160 % of the phase setting, which matters when coordinating selectivity on a 4-wire distribution bus.
Interrupting capacity and selectivity
Short-circuit ratings span 440 kA at 240 V down to 53 kA at 690 V, so this breaker can sit at the main or subfeed position in a high-fault installation without needing a current-limiting upstream device. The 330 kA rating at 415 V and 440 V covers common industrial distribution voltages across Europe and Asia; the 220 kA at 500 V suits Canadian 480Y/277 V panels. These figures are the SCCR the breaker itself can clear — the panel's overall SCCR still depends on the weakest component in the feeder.
Trip unit and protection profile
The ETU550 is an electronic trip unit with adjustable long-time pickup and delay (tr min. 0.5 s, tr max. 25 s), plus the N-conductor protection can be set to OFF or between 40 % and 160 % of the phase current setting. That adjustability lets you tune the breaker to the actual cable and load without swapping trip packs. Rated insulation voltage is 800 V, and the maximum power loss at rated current is 0.5 W — negligible for thermal budgeting inside a crowded enclosure.
Physical fit and panel integration
Dimensions are 181 mm high, 140 mm wide, 86 mm deep — a standard 4-pole MCCB footprint that fits SENTRON mounting plates and common DIN-rail adapters. The front face carries an IP40 protection class, adequate for enclosed panel mounting where no water ingress is expected. Storage range is -40 °C to 80 °C; the -40 °C operating floor matches cold-weather or unheated substation environments.