What this MCCB carries and where it fits
The Siemens 3VA2040-5KP36-0AA0 is a SENTRON molded case circuit breaker (MCCB) rated for 40 A continuous at 40 °C, with no derating needed up to 70 °C — the full 40 A holds across the entire operating temperature range. That means for a panel running hot near the top of a cabinet, you still get the full rated current without having to oversize. Three-pole construction, line protection version, with the ETU850 electronic trip unit. The ETU850 gives you adjustable overload and short-circuit protection curves, plus communication capability — this breaker talks to your control system, not just trips in isolation. Interrupting capacity is 187 kA at 240 V AC, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3 kA at 690 V. At 415 V — the common European distribution voltage — that 121 kA gives serious fault-current headroom for most industrial service-entrance or feeder applications.
Panel fit and physical integration
Dimensions: 105 mm wide, 181 mm high, 86 mm deep. That 105 mm width is the standard 3-pole MCCB footprint for this class — it fits existing SENTRON mounting bases and busbar systems without adapters. Front protection is IP40 — suitable for general indoor panel installation where no washdown or dust ingress is expected. The IP40 rating means tools or fingers won't accidentally contact live parts from the front, but the breaker is not sealed against water jets.
What the ETU850 trip unit gives you
The ETU850 is an electronic trip unit with communication function — it can report status, trip events, and load current over a bus, enabling predictive maintenance and remote monitoring. No undervoltage release or shunt trip is built in (those are optional add-ons), but the motor-drive option is available as a field-installable accessory. Power loss is 2.2 W maximum — negligible for thermal budgeting in a crowded panel, but worth noting if you are calculating total heat load for a sealed enclosure.