What this MCCB delivers on the line
The Siemens 3VA2140-5MN32-0BH0 is a 3-pole SENTRON molded case circuit breaker rated 40 A continuous current with an ETU350M electronic trip unit. It carries a 187 kA interrupting capacity at 240 V and still holds 121 kA at 415 V and 440 V — that's extreme SCCR for a 40 A frame, meaning it can sit upstream of a high-fault panel without cascading failure. At 690 V the rating drops to 17 kA, so watch your system voltage if you're pushing toward the top of the insulation class.
Thermal derating and panel fit
The breaker carries full 40 A from 40 °C up to 50 °C with no derating — that covers most ventilated enclosures. Above 50 °C it rolls off gradually: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. That 10% drop at the top end still leaves headroom for a 30 A motor load in a hot cabinet. The 75 W maximum power loss means you need to account for heat dissipation if the breaker is packed tight with other devices.
Built-in undervoltage release and auxiliary signaling
This variant includes an integrated undervoltage release (UVR) — no external module needed. It also ships with 2 auxiliary switches plus 1 trip alarm switch (HQ type), giving you three separate signal paths for remote status monitoring. The trip indicator on the front gives a local visual flag when the breaker has tripped on fault.
Motor protection with ETU350M
The ETU350M electronic trip unit is configured for motor protection — it includes phase failure detection (monitors all three phases) and an LSI trip curve (long-time, short-time, instantaneous). That means it can protect a motor against overload, short circuit, and single-phasing without a separate motor protection relay. The 20 000 latching endurance cycles reflect the mechanical life of the switching mechanism under normal operation.