MCCB for panel builders
The Siemens SENTRON 3VA1120-4EF36-0CH0 is a 3-pole molded case circuit breaker rated 20 A at 40 °C ambient, with a breaking capacity of 121 kA at 240 V AC — enough to handle high-fault utility feeds in industrial distribution panels. The line-protection design means it trips on overload and short-circuit, not on ground fault; the undervoltage release (UVR) lets a safety PLC or E-stop chain drop the breaker when control voltage disappears. Panel builders mounting on DIN rail or direct plate will find the 70 mm depth and 76.2 mm width fit standard MCCB footprints.
Breaking capacity and thermal derating
Rated uninterrupted current holds at 20 A from 40 °C through 55 °C, then derates to 19 A at 60 °C and 19 A at 70 °C — no derating loss in typical 40 °C panel ambient. The interrupting ratings cover the common distribution voltages: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 500 V and 690 V. Insulation voltage is rated 800 V, so the breaker can be applied in 690 V line-to-line systems with adequate clearance.
Auxiliary and release configuration
Factory-fitted with 2 auxiliary switches plus 1 trip alarm switch (HQ configuration) — enough to signal breaker position and fault status back to a PLC or SCADA. The undervoltage release (UVR) is built in; no external undervoltage module needed. Maximum power loss is 14.5 W, relevant for thermal budgeting inside a sealed enclosure.
Environmental limits
Operating ambient range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage minimum is below typical warehouse conditions, so no cold-weather handling restrictions.