The Siemens SENTRON 3VA1120-5EF36-0BA0 is a 3-pole molded case circuit breaker (MCCB) rated for 20 A continuous at 40 °C through 55 °C, with a TM240 thermal-magnetic release designed for line protection. It carries an interrupting capacity of 187 kA at 240 V AC, 121 kA at 415 V, and 75.6 kA at 440 V — figures that cover most industrial distribution panels without needing a current-limiting upstream device.
Interrupting capacity and thermal performance
The 187 kA at 240 V is the headline number, but the 121 kA at 415 V is the one that matters for most European 400 V panels — it means this breaker can sit at the main distribution point without a series fuse. At 690 V it still holds 17 kA, covering motor control centers on 690 V industrial grids. Thermal derating is minimal: the breaker holds 20 A from 40 °C to 55 °C, then drops only 1 A at 60 °C and 65 °C, and 19 A at 70 °C. That flat curve means you don't have to oversize the frame for a warm enclosure — it's already accounted for in the design. Rated insulation voltage is 800 V, so the breaker's internal clearances and creepage are sized for 690 V systems with margin. Power loss at rated current is 14.5 W maximum — manageable for a DIN-rail or panel-mount enclosure without forced ventilation.
Built-in undervoltage release
This variant includes an undervoltage release (UVR) as the auxiliary release — part of the order code's 'EF36' suffix. That means the breaker trips automatically when supply voltage drops below a threshold, which is standard for safety circuits (e.g., emergency-stop chains or machine isolation where you want the breaker open on power loss). No separate UVR module to buy and wire.
Physical fit and panel integration
Dimensions are 130 mm height, 76.2 mm width, 70 mm depth — a 3-pole MCCB that fits standard 3-pole panel space. The 70 mm depth means it clears most 200 mm deep enclosures with room for wiring gutters. No special adapter plate needed for a standard DIN-rail mount.