What it is and what it does
The Siemens 3VA1125-5EF32-0JH0 is a SENTRON molded case circuit breaker (MCCB) built for line protection — it sits on the incoming feed to protect downstream wiring and loads from short circuits and overloads. Three poles, rated 25 A continuous at 40 °C, and it holds that same 25 A rating all the way up to 50 °C before it starts to derate (24 A at 55 °C, 23 A at 70 °C). That thermal stability matters if this breaker lands in a warm panel or near other heat sources.
Breaking capacity — where this thing earns its keep
The headline number is 187 kA at 240 VAC. That's a massive interrupting rating for a 25 A frame — it's designed for high-fault locations like a service entrance or a large transformer secondary where available fault current is brutal. At 415 V it still handles 121 kA, at 440 V it's 75.6 kA, and it stays at 17 kA through 500 V and 690 V. For a 25 A MCCB, that's serious headroom; you're not going to run out of SCCR on a typical industrial panel.
What's built into this variant
This order code ships with a shunt trip release (STL) for remote tripping, plus two auxiliary switches and one trip alarm switch (HQ). That's enough feedback for a PLC to know the breaker position and whether it tripped on fault versus being opened manually. It also has a voltage trip indicator — a mechanical flag that stays latched after a trip so you can walk the panel and see which breaker opened. No undervoltage release, no ground-fault monitoring, no communication module. It's a pure line-protection MCCB with remote trip capability and status contacts.
Panel fit and integration
Footprint is 130 mm high, 76.2 mm wide, 70 mm deep. That 3-inch width is standard for a 3-pole MCCB in this class — it'll drop into a SENTRON panelboard or a DIN-rail adapter without surprises. Rated insulation voltage is 800 V, so it's comfortable in 480/277 V and 600 V systems. Maximum power loss is 8.5 W — negligible for panel heat calculations, but factor it in if you're stuffing a dozen of these in a sealed enclosure.