Siemens 3VA1120-6EF32-0AD0 — 20 A MCCB with TM240 release, 220 kA at 240 V
The Siemens SENTRON 3VA1120-6EF32-0AD0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current Iu of 20 A, fitted with a TM240 thermal-magnetic overcurrent release. Its headline interrupting rating is 220 kA at 240 V, dropping to 154 kA at 415 V and 121 kA at 440 V — figures that place it in the high-capacity tier of the 3VA line, sized for fault currents at the main distribution board rather than a downstream subfeed. The TM240 release is a fixed thermal-magnetic unit — no interchangeable trip block, no electronic adjustment. That means the 20 A rating is the hard ceiling; if the load draws more, step up to the next frame size. The breaker carries three HQ auxiliary switches, which gives the panel builder a spare N.O./N.C. pair beyond the standard alarm contact for remote status or PLC feedback. Mounts on a DIN rail or panel-mount base in a standard enclosure. The front face is IP40 rated — protected against tools and wires >1 mm, but not sealed against washdown. Keep it inside a cabinet unless you add a cover.
Thermal derating and operating range
The 20 A rating holds flat from 40 °C to 50 °C. Above that it begins to taper: 19.2 A at 55 °C, 18.8 A at 60 °C, 18.4 A at 65 °C, and 18 A at 70 °C (–). If the panel ambient runs hot — say a crowded enclosure near a drive — the effective continuous current drops by roughly 10 % at the top end. The operating temperature range is -25 °C to 70 °C; storage extends from -40 °C to 80 °C (–).
Selectivity and coordination notes
With a 220 kA breaking capacity at 240 V, this MCCB can sit at the service entrance or as the main feeder in a panel where the available fault current is high. The 800 V rated insulation voltage covers 480 V and 600 V class systems with margin. For DC applications, Siemens directs the installer to the 3VA device manual — the standard AC interrupting ratings do not apply in DC circuits.