The Siemens SENTRON 3VA2140-5MN32-0AB0 is a 3-pole molded case circuit breaker rated for 40 A continuous current across the full ambient range from 40 °C to 70 °C — no derating needed up to that ceiling. Interrupting capacity hits 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3.7 kA at 690 V. That SCCR headroom makes it a strong choice for high-fault panels where a standard 25 kA or 36 kA breaker would need upstream fusing or a larger frame. This is a motor-protection-design MCCB — it includes phase failure detection, so it trips on loss of one phase before the motor single-phases and cooks. Physically it measures 105 mm wide, 181 mm tall, 86 mm deep — a compact 3-pole footprint that fits standard Siemens 3VA panel cutouts and busbar systems. The basic switch inside is order code 3VA21405MN320AA0, meaning the trip unit and mechanism are integral; no separate plug-in module to source.
How it handles the ambient heat from adjacent gear
The 40 A rating holds flat across the entire 40–70 °C operating band — no derating curve to calculate when the breaker sits next to a warm drive or transformer in a closed panel. Maximum power loss is 1.6 W, so internal heating from the breaker itself is negligible in the enclosure thermal budget.