Key ratings and what they mean for fit
The Siemens 3VA1120-5ED22-0AA0 is a SENTRON molded case circuit breaker (MCCB) in the line protection version, rated for a continuous current Iu of 20 A across the ambient range from 40 °C to 55 °C — it holds 20 A flat through that band, then derates to 19 A at 60 °C through 70 °C. That thermal stability means the breaker doesn't force a cable upsize just because the panel runs warm; the trip curve stays consistent within the normal enclosure temperature envelope. The interrupting capacity is the headline number here: 187 kA at 240 V AC and 121 kA at 415 V AC. Those are high-rupturing-capacity figures for a 20 A frame — this breaker can sit at the service entrance or on a high-fault panel where the available short-circuit current is substantial, without needing a current-limiting fuse upstream. The 2-pole configuration suits single-phase or two-leg line protection.
Mounting and panel integration
The breaker measures 70 mm deep by 50.8 mm wide by 130 mm high — a 2-inch-wide footprint. The front face carries an IP40 protection rating.
Adjustable trip settings and release design
The overcurrent release is a TM210 — thermal-magnetic, fixed thermal and magnetic adjustment. The Ir is fixed at 20 A. The instantaneous magnetic pickup Ii is set at 320 A.
Electrical ratings and approvals context
Rated insulation voltage Ui is 500 V AC; maximum DC operational voltage is 250 V. The power loss at rated current is 8 W maximum. Storage temperature range is -40 °C to 80 °C; operating ambient is -25 °C to 70 °C.