What this MCCB carries and where it fits
The SENTRON 3VA1120-4EF36-0AD0 is a 3-pole molded case circuit breaker rated 20 A at 40 °C, with a TM240 thermal-magnetic overcurrent release. Its interrupting capacity hits 121 kA at 240 V AC and still holds 75.6 kA at 415 V — enough for high-fault utility feeds or transformer secondaries where standard MCBs would weld shut. Designed for line protection (not motor or generator protection), it sits in a 76.2 mm wide, 130 mm tall, 70 mm deep envelope — a standard 3-pole MCCB footprint that drops into most SENTRON panelboards and distribution blocks without re-drilling gland plates. Rated insulation voltage is 800 V, and the breaker carries three HQ auxiliary switches for status feedback to a PLC or remote I/O — no separate auxiliary contact block needed if your BOM already calls for three NO/NC signals.
Breaking capacity — what the numbers mean for your fault level
At 240 V the breaker clears 121 kA symmetrical; at 415 V it still manages 75.6 kA. Those are the numbers that decide whether this MCCB holds under a bolted fault on a 1000 kVA transformer secondary. Drop to 500 V and the capacity is 11.9 kA — still adequate for most 480 V industrial services, but check your available fault current at the panel main lugs before committing the BOM line. The TM240 release is fixed thermal-magnetic — no electronic adjustment, no communication module. That keeps the part simple and reliable for a distribution feeder where you set it once and forget it. Power loss maxes at 12 W, so heat buildup in a densely packed enclosure is manageable without forced ventilation.
Panel fit and wiring notes
Width 76.2 mm (3 in), depth 70 mm (2.76 in), height 130 mm (5.12 in) — fits standard SENTRON mounting plates and DIN-rail adapters. The three auxiliary switches (HQ type) are factory-installed; no field-add module needed. No undervoltage release, no shunt trip, no ground-fault monitoring on this variant — if your circuit requires any of those, you need a different suffix. Operating temperature range is -25 °C to 70 °C; storage from -40 °C to 80 °C. Current derating starts at 60 °C where it drops from 20 A to 19 A, and holds at 19 A through 70 °C — minimal thermal penalty in a warm cabinet.