This is a line-protection design — meaning it's configured for feeder and distribution duty, not motor-starting or generator protection. The ETU350 provides adjustable long-time, short-time, instantaneous, and ground-fault protection curves, which gives the specifying engineer selectivity headroom downstream without sacrificing trip speed on a hard fault.
Interrupting capacity and voltage class
This MCCB delivers 187 kA interrupting capacity at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 3 kA at 690 V.
That's unusual for a molded case breaker; most lose 10–15 % by 60 °C. Power dissipation at full load is 5.4 W, which is manageable for dense panel layouts.
Dimensions are 181 mm height, 140 mm width, 86 mm depth. The 140 mm width for a 4-pole frame is standard for this SENTRON class; it matches the mounting footprint of the 3VA2 family, so a panel drilled for a 3VA2040-8HN42-0AA0 will accept this unit without re-drilling or bus-bar rework, provided the lugs accept the same conductor size.
The lifecycle stage is listed as current — meaning Siemens has not issued an end-of-life notice, and the part remains in the active catalog. No successor order code has been published.
Front-face protection class is IP40 — suitable for dry indoor panel mounting where no water jets or dust ingress are expected. The breaker carries no undervoltage release, no shunt trip, and no communication function as configured; it is a standalone thermal-magnetic replacement with electronic trip adjustment accessible on the front face.