What the ratings mean for your panel
The Siemens SENTRON 3VA1120-6EF36-0DH0 is a 3-pole molded case circuit breaker (MCCB) rated 20 A continuous at 40 °C, with a breaking capacity of 220 kA at 240 VAC — that figure drops to 154 kA at 415 V, 121 kA at 440 V, and 17 kA at 500 V or 690 V. The 220 kA at 240 V is the headline number for high-fault service-entrance or distribution panels where the available fault current is substantial; the 17 kA at 690 V tells you this breaker is not intended for 690 V motor circuits unless the upstream transformer limits fault current to that level. Rated insulation voltage is 800 V, so the internal clearances and creepage are sized for 690 V systems. Current rating holds at 20 A from 40 °C through 55 °C, then derates to 19 A at 60 °C and 65 °C, and stays at 19 A at 70 °C. That flat derating curve means the breaker can be installed in a warm enclosure without losing ampacity until the ambient passes 55 °C — useful for panels packed near other heat sources. The breaker is designed for line protection (not motor or generator protection), so its thermal-magnetic trip curve is set for cable and busbar protection in distribution. It includes a trip indicator and an undervoltage release (UVR) as standard — the UVR will open the breaker if the control voltage drops below a threshold, which is common in emergency-stop or undervoltage protection schemes. The auxiliary switch configuration is 2 auxiliary switches plus 1 trip alarm switch (HQ), giving you three dry contacts for status feedback to a PLC or remote indicator.
Panel fit and mounting
The 3VA1120-6EF36-0DH0 measures 130 mm high, 76.2 mm wide, and 70 mm deep. At 76.2 mm (3 inches) wide, it occupies a standard 3-pole MCCB footprint on a DIN rail or mounting plate. The 70 mm depth is the body depth — account for additional clearance behind the door for handle operation and wiring. Maximum power loss is 14.5 W, which factors into enclosure thermal calculations if the panel is sealed.