What this MCCB carries and where the ratings matter
The Siemens 3VA1125-3GE46-0AA0 is a SENTRON 4-pole molded case circuit breaker rated 25 A continuous with a TM220 thermal-magnetic trip unit. That TM220 designation means the thermal element is fixed at 25 A and the magnetic short-circuit pickup is fixed at 220 A — no field-adjustable dials on the overload or instantaneous settings. For a line protection role (not motor protection with adjustable overloads), this suits feeder circuits, distribution panels, and branch protection where the load current is stable and known. Interrupting capacity is voltage-dependent: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V. These are symmetrical RMS values. At 415 V — common in European industrial distribution — the 52.5 kA figure gives solid headroom for most panelboards with high-fault utility feeds. At 690 V the 11.9 kA rating is the binding constraint; verify the available fault current at the installation point before committing the BOM line. Thermal derating is published across the full ambient range: full 25 A from 40 °C through 50 °C, then 24 A at 55 °C and 60 °C, then 23 A at 65 °C and 70 °C. That means in a warm panel — say 55 °C inside the enclosure — the breaker is still good for 24 A continuous, which is 96 % of its nameplate. No forced derating needed until you cross 50 °C. Dimensions are 130 mm high, 101.6 mm wide, 70 mm deep. The 4-pole width (101.6 mm) is roughly 4 inches — standard for a 4-pole MCCB in this frame size. Front protection is IP40, so it keeps tools and fingers out but is not sealed against moisture; mount inside a rated enclosure for wet or washdown areas.
Panel fit and integration notes
The 3VA1125-3GE46-0AA0 mounts on a DIN rail or can be screw-fixed to a backplate. The 4-pole construction with 100 % N-conductor protection means the neutral pole is fully rated and switches with the phases — no derating or separate neutral bar needed for solidly-grounded systems. The TM220 release has no external accessory slot for a shunt trip or undervoltage release without the optional motor drive extension (available as a field-fit accessory). Rated insulation voltage Ui is 800 V, and maximum DC operational voltage is 600 V. The storage range (-40 °C to 80 °C) exceeds the operating range (-25 °C to 70 °C), so the breaker can sit in an unheated warehouse or a hot shipping container without damage. Power loss at rated current is 8.5 W maximum — negligible for panel thermal calculations but worth noting if the enclosure is densely packed.