The Siemens SENTRON 3VA1120-5EF36-0DA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 20 A across ambient temperatures from 40 °C to 55 °C without derating. Above 55 °C, it steps down to 19 A through 70 °C. Breaking capacity is the headline here: 187 kA at 240 V AC, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. That 187 kA at 240 V means it can safely interrupt very high fault currents typical on the secondary side of large distribution transformers — a spec that matters for selectivity studies in heavy industrial switchboards. The TM240 thermal-magnetic release provides fixed thermal and magnetic trip settings, with no trip indicator and no communication function. An undervoltage release (UVR) is built in — the auxiliary release type is listed as undervoltage release, so the breaker will trip if control voltage drops below the release threshold, a common requirement for safety circuits and emergency-stop chains.
Panel fit and mounting
Footprint is 76.2 mm wide, 130 mm tall, 70 mm deep — a standard 3-pole MCCB width that fits most DIN-rail or panel-mount enclosures without surprises. The 70 mm depth is shallow enough for compact gland-plate layouts, but verify the handle-knuckle clearance if the panel door has a shallow backpan. Rated insulation voltage is 800 V, so the breaker is suitable for 480/277 V and 600 V systems with headroom. Maximum power loss is 14.5 W — negligible for thermal calculations in a ventilated enclosure, but worth noting if the panel is sealed and densely packed.