Siemens 3VA1120-5EF36-0HC0 — SENTRON 3-pole MCCB, 20 A, line protection
The Siemens 3VA1120-5EF36-0HC0 is a SENTRON molded case circuit breaker (MCCB) configured for line protection. It carries a rated continuous current Iu of 20 A and a rated insulation voltage Ui of 800 V. The 3-pole frame is fitted with a TM240 thermal-magnetic overcurrent release and a shunt trip (STL) auxiliary release. Breaking capacity reaches 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V — figures that define the maximum fault current the device can safely interrupt at each voltage level, which is the primary selection criterion for SCCR compliance in a distribution panel.
Thermal derating and operating range
The 20 A rating holds flat from 40 °C through 50 °C. At 55 °C it derates to 19.2 A, at 60 °C to 18.8 A, at 65 °C to 18.4 A, and at 70 °C to 18 A. If the panel ambient runs above 50 °C, the continuous load must be reduced per these values — a common oversight when a breaker is sized at the nameplate current without accounting for enclosure heat rise. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Integrated auxiliary and release configuration
This MCCB ships with 2 auxiliary switches (HQ type) and a shunt trip release (STL). The integrated auxiliary trip is order code 3VA9688-0BL30. There is no undervoltage release, no ground fault monitoring, no phase failure detection, and no communication function — the part is a straightforward line-protection device without remote monitoring or GFCI capability. The front face carries IP40 protection; the enclosure is sized at 130 mm height, 76.2 mm width, and 70 mm depth, which governs the DIN-rail or mounting-plate footprint.