The Siemens SENTRON 3VA1120-4EF36-0AB0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 20 A at 40 °C with a TM240 thermal-magnetic release. Its interrupting capacity reaches 121 kA at 240 V and 75.6 kA at 415 V, making it a fit for high-fault panels where upstream coordination demands a robust SCCR. The 800 V rated insulation voltage supports 480Y/277 V and 600 V delta systems with headroom.
Interrupting capacity and thermal derating
At 440 V the breaker clears 52.5 kA; at 500 V and 690 V it holds at 11.9 kA. The thermal curve holds 20 A flat from 40 °C through 55 °C, then derates to 19 A at 60 °C and 70 °C. That means the breaker does not lose ampacity until the ambient passes 55 °C — useful in a tightly packed panel where internal temperature runs high.
Physical fit and integration
The breaker measures 70 mm deep, 76.2 mm wide, and 130 mm tall. It mounts on a DIN rail or directly to a panel backplate via the SENTRON mounting base. The 3-pole footprint matches standard SENTRON 3VA1 MCCB cutouts; if you are swapping a 3VA1110-5EF32-0AM0, the width and depth are identical, so no re-drilling or bus-bar rework is needed. Two auxiliary switches (HP type) are built in for status feedback to a PLC or annunciator.
Operating environment
Rated for operation from -25 °C to 70 °C, with storage from -40 °C to 80 °C. Maximum power loss is 12 W — negligible for panel thermal budgeting, but worth noting if the breaker is enclosed in a small non-ventilated box.