Siemens SENTRON 3VA1120-5EF36-0CH0 — 20 A MCCB for line protection
The Siemens SENTRON 3VA1120-5EF36-0CH0 is a 3-pole molded case circuit breaker rated for 20 A continuous current (Iu) with a TM240 thermal-magnetic release. It's built for line protection in distribution panels, not for motor-starting duty — no phase-failure detection or communication module on board. Interrupting capacity hits 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V — enough headroom for most industrial service-entrance or feeder applications where high fault current is expected. The 800 V rated insulation voltage (Ui) matches the 690 V interrupting test voltage range. Thermal derating is minimal up to 50 °C (still 20 A), then drops to 19.2 A at 55 °C, 18.8 A at 60 °C, 18.4 A at 65 °C, and 18 A at 70 °C. If the panel ambient runs above 50 °C, factor in that 1–2 A reduction when sizing the load.
Auxiliary contacts and undervoltage release
Comes with 2 auxiliary switches plus 1 trip alarm switch (HQ type) and an integrated undervoltage release (UVR) — wired separately from the main power path. The UVR coil drops the breaker if control voltage is lost, common for emergency-stop chains or undervoltage protection schemes. The auxiliary trip accessory is order code 3VA9608-0BB24, a separate line item if you need a shunt trip or additional signaling. No ground-fault monitoring or voltage-trip module is fitted on this variant.
Mechanical dimensions and panel fit
Footprint: 70 mm deep, 76.2 mm wide, 130 mm tall. The 76.2 mm width is a standard 3-pole MCCB form factor — fits most DIN-rail or screw-mount panel layouts without surprises. IP40 on the front face (finger-safe), no IP rating on the rear or sides.