What this breaker does — and what the ratings mean for your panel
The Siemens 3VA1125-5EF32-0BC0 is a SENTRON molded case circuit breaker (MCCB) rated for line protection. It carries 25 A continuously at 40 °C ambient, derating to 23 A at 70 °C — so if your panel runs hot near the top of the enclosure, you need to account for that drop. The 187 kA interrupting rating at 240 V is the headline number, but note it drops to 121 kA at 415 V and 75.6 kA at 440 V; at 500 V or 690 V it's still 17 kA. That means this breaker handles high-fault utility feeds at low voltage but is still usable on 480 V systems with moderate available fault current. The 800 V rated insulation voltage (Ui) confirms it's built for 690 V line-to-line applications. It ships with an undervoltage release (UVR) and two HQ auxiliary switches — the UVR means the breaker trips if control voltage drops, which is standard for emergency-stop or undervoltage protection schemes. The auxiliary switches give status feedback to a PLC or indicator lamp without extra wiring. No trip indicator or voltage trigger on this variant, so don't plan on local fault annunciation from the breaker face.
Mounting and panel fit
The 3VA1125-5EF32-0BC0 measures 130 mm high, 76.2 mm wide, and 70 mm deep. That 3-inch width (76.2 mm) is the standard 3-pole MCCB footprint — it fits the same DIN-rail or screw-mount slots as other SENTRON 3VA1 breakers. The 70 mm depth means it clears most 200 mm deep enclosures with room for wiring gutters. If you're swapping out a competitor's 3-pole MCCB, check the mounting hole pattern; Siemens uses a 90 mm center-to-center on the base, which is common but not universal.