SENTRON 3VA1125-5EF36-0BC0 — 25 A MCCB with undervoltage release
The Siemens SENTRON 3VA1125-5EF36-0BC0 is a 3-pole molded case circuit breaker (MCCB) rated 25 A at 40 °C, designed for line protection in distribution panels. Its 187 kA interrupting capacity at 240 V AC means it can safely clear a fault up to that level without upstream damage — critical for high-fault installations like industrial mains or transformer secondaries. The integrated undervoltage release (UVR) trips the breaker when supply voltage drops below a set threshold, protecting motors and controls from brownout conditions.
Breaking capacity across voltages — selectivity headroom
At 415 V the breaker still delivers 121 kA, dropping to 75.6 kA at 440 V and 17 kA at both 500 V and 690 V. That 17 kA floor at 690 V is the limiting case for coordination studies — if your upstream transformer can deliver more than 17 kA at 690 V, this breaker won't hold selectivity and you need a higher-rated frame. The 800 V rated insulation voltage confirms the internal clearances handle 690 V line-to-line without tracking.
Thermal derating and power loss
Rated current holds at 25 A from 40 °C through 50 °C (–), then derates to 24 A at 55 °C and 60 °C, and 23 A at 65 °C and 70 °C. In a sealed, uncooled panel at 55 °C ambient, plan for 24 A continuous — the 25 A nameplate applies only up to 50 °C. Maximum power loss is 11 W, which matters for thermal budgeting in dense DIN-rail layouts.
Physical fit and auxiliary configuration
Footprint is 76.2 mm wide by 130 mm tall by 70 mm deep — standard 3-pole MCCB width for a 25 A frame. Ships with two factory-fitted HQ auxiliary switches and the undervoltage release. No communication function and no ground-fault monitoring — this is a pure line-protection device with UVR trip, not a metering or GFCI variant. The basic switch order code is 3VA11255EF360AA0 if you need a bare breaker without auxiliaries.
Lifecycle and sourcing
Lifecycle stage is marked current — this is an active, in-production catalog number. No successor or phase-out notice applies. The part is sourced and quoted to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time.