Siemens 3VA1120-3EF36-0CH0 — SENTRON 3-pole MCCB, 20 A, line protection
The Siemens 3VA1120-3EF36-0CH0 is a SENTRON molded case circuit breaker (MCCB) rated for a continuous current Iu of 20 A across a 3-pole configuration, with a TM240 thermal-magnetic overcurrent release. Its interrupting capacity scales with system voltage: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V — so at 415 V it clears a 52.5 kA fault without upstream coordination failure, which is the figure that governs most industrial panel SCCR compliance. The breaker carries an undervoltage release (UVR) and two auxiliary switches plus one trip alarm switch HQ (order code 3VA9608-0BB24 for the integrated auxiliary trip). No communication function, no phase failure detection, no ground fault monitoring — this is a pure line-protection device, not a power monitor.
Thermal derating and mechanical endurance
Rated continuous current holds at 20 A from 40 °C through 50 °C ambient; above that it derates linearly to 18 A at 70 °C. The breaker is rated for 15 000 mechanical operations — that is the latching endurance figure, so it is sized for moderate switching duty in a distribution panel, not for continuous motor starting. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Front protection is IP40 — suitable for enclosed panel mounting, not for washdown environments.
Physical footprint and panel fit
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. The 76.2 mm width is a standard 3-pole MCCB footprint — it fits the same DIN-rail or panel-mount cutout as other SENTRON 3VA1 3-pole units. The 70 mm depth leaves clearance for rear-access busbars in a typical 200 mm deep enclosure.