Integrator note — 40 A MCCB with TM210 release
The Siemens SENTRON 3VA1040-3ED36-0AF0 is a 3-pole molded case circuit breaker rated for 40 A continuous current (Iu) at up to 50 °C ambient, with a TM210 thermal-magnetic release. The interrupting ratings step down from 75.6 kA at 240 V to 52.5 kA at 415 V and 32 kA at 440 V — enough headroom for most distribution panels fed by a typical 500 kVA transformer. At 690 V it still clears 7.5 kA, so it can serve as the main breaker on a 690 V motor control center branch. The TM210 release means the thermal element is fixed at 40 A (no dial adjustment), while the magnetic pickup is fixed at 10× In (400 A). No undervoltage release, no shunt trip, no communication module — this is a straight line-protection breaker for panels where remote tripping or metering isn't required.
Thermal derating and panel fit
The 3VA1040-3ED36-0AF0 holds its full 40 A rating up to 50 °C. Above that it derates linearly: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. In a sealed, uncooled panel that sees 60 °C internal ambient, plan for a 37.6 A continuous load ceiling. The breaker occupies 76.2 mm width (3-pole fixed), 130 mm height, and 70 mm depth — standard SENTRON 3VA footprint for a 40 A frame. IP40 on the front face means it's protected against tools and wires >1 mm, but not against water ingress; mount inside a panel with a door. The auxiliary contact configuration is 1 N/O + 1 N/C switch plus a separate trip alarm contact (HQ type), wired via the front accessory slot.
Coordination and selectivity notes
The TM210 release has a fixed long-time delay (tr) of 1 second at 6× In per the IEC 60947-2 thermal curve. This gives a defined coordination band with downstream miniature circuit breakers: a 40 A MCCB feeding a 16 A MCB on a lighting panel will hold through a bolted fault at the sub-panel terminals up to roughly 10 kA, depending on cable impedance. The 15000-cycle latching endurance covers the mechanical life; electrical endurance is lower under full-load switching but adequate for a distribution breaker that operates a few times a year. No phase-failure detection or ground-fault monitoring is built in — those require the 3VA accessory modules (undervoltage release, shunt trip, or RCD block) ordered separately.