The Siemens SENTRON 3VA1120-4GF42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 20 A continuous current, with a TM240 thermal-magnetic release designed for line protection. It carries a 121 kA interrupting capacity at 240 V AC, dropping to 75.6 kA at 415 V and 52.5 kA at 440 V — the numbers you need for a fault-current study on a 480 V panel. The 800 V rated insulation voltage gives headroom for 690 V systems without series-derating the breaker.
DIN-rail footprint and panel fit
At 70 mm deep, 101.6 mm wide, and 130 mm tall, this MCCB occupies a standard 4-module-wide slot on a DIN rail. The IP40 front protection means it's fine inside a closed panel but not for washdown areas. Maximum power dissipation is 12 W — account for that in your thermal budget if you're packing a row of these in a shallow enclosure.
Temperature derating and real-world current
The 20 A rating holds flat from 40 °C to 55 °C (–). At 60 °C and 65 °C it derates to 19 A, and at 70 °C it's still 19 A. If your panel ambient runs above 55 °C, you lose 1 A — not a deal-breaker for a 20 A feeder, but worth knowing if you're loading it at 95 % continuously. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Lifecycle status is current production. No phase-out or last-time-buy notice is on record. This part is sourced to order against an RFQ through independent distribution — availability and current pricing confirmed at quote time.