Breaking capacity and temperature derating
The 3VA1120-3EF32-0JA0: Breaking capacity is rated at 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V — these numbers tell you the maximum fault current the breaker can safely interrupt at each voltage level. For a 20 A frame, that's a high-interrupting rating, meaning it can handle substantial fault energy without welding or rupturing. The rated insulation voltage is 800 V, so it's suitable for 480/277 V and 600 V panels as well. Thermal derating is published across the operating range: the breaker carries a full 20 A from 40 °C through 50 °C, 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 your panel ambient runs above 50 °C, you need to account for that reduction — the 20 A rating is only valid up to 50 °C. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Mounting and integration
Dimensions are 130 mm height, 76.2 mm width, 70 mm depth — a standard 3-pole MCCB footprint that fits most distribution panelboards and switchgear cubicles. Front IP40 protection means it's splash-resistant from the front but not sealed; install it inside a cabinet or enclosure. The breaker has no auxiliary contacts, no undervoltage release, no communication function, and no phase-failure detection — it's a basic thermal-magnetic unit with a shunt trip (STL) as the only auxiliary release option (order code 3VA9688-0BL32 for the integrated auxiliary trip). Latching endurance is rated at 15,000 operations, which is typical for a distribution-grade MCCB.