What this MCCB carries
The Siemens SENTRON 3VA1120-4EF36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection duty. It carries a 20 A continuous current at 40 °C ambient — no derating needed up to 55 °C where it still holds 20 A, then drops to 19 A at 60 °C through 70 °C. That thermal curve makes it a straight pick for a panel running warm but not hot; no need to oversize for a 50 °C enclosure interior. Breaking capacity hits 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 500 V or 690 V. That 121 kA figure at 240 V means it handles high-fault utility feeds without cascading upstream — common in North American 240/120 V split-phase service entrances or large 240 V motor control centers. The 75.6 kA at 415 V covers European 400 V distribution.
TM240 release and protection design
The overcurrent release is the TM240 thermal-magnetic type — fixed thermal pickup with magnetic short-circuit trip. No trip indicator, no undervoltage release, no ground-fault monitoring, no communication function. This is a plain-vanilla line protection breaker: no accessories inside the frame, so what you see on the nameplate is what the BOM gets. Insulation voltage rated at 800 V, which covers 690 V systems with margin.
Panel fit and environment
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. That 70 mm depth is shallow enough for most 200 mm deep enclosures — leaves room for wiring gutters behind the backplane. IP40 on the front means dry indoor panels only; no washdown. Operating range -25 °C to 70 °C, storage -40 °C to 80 °C. Max power loss 12 W — negligible heat contribution in a ventilated enclosure.