Line-side protection, 20 A, 220 kA at 240 V
The Siemens SENTRON 3VA1120-6GF42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 20 A continuous current with a TM240 thermal-magnetic overcurrent release. Its interrupting capacity hits 220 kA at 240 V AC, dropping to 154 kA at 415 V and 121 kA at 440 V — still substantial for most distribution panels. At 500 V and 690 V it holds 17 kA, which covers the low-end fault duty on smaller transformers. This MCCB is designed for line protection — primary feeder or large subfeed duty — not motor branch-circuit protection. The TM240 release gives a fixed thermal curve and magnetic trip, so coordination studies need the published time-current curve for selectivity with downstream breakers. The 70 mm depth and 101.6 mm width fit standard Siemens SENTRON panel footprints. Front IP40 protection handles dry enclosure environments; no washdown rating.
Thermal derating and operating range
The breaker holds full 20 A rating from 40 °C through 55 °C ambient. At 60 °C it derates to 19 A, holding that level through 70 °C. Operating ambient spans -25 °C to 70 °C; storage from -40 °C to 80 °C. Maximum power loss is 12 W at rated load.