The Siemens SENTRON 3VA1125-4EF42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 25 A across its full ambient range up to 50 °C before the first derate step. At 55 °C it holds 24 A, at 65 °C it holds 23 A, and at 70 °C it holds 23 A — so in a warm panel you lose about 1 A per 5 °C above 50 °C. The TM240 thermal-magnetic release means the thermal element is fixed-trip at 25 A; the magnetic instantaneous pickup is factory-set and not field-adjustable.
Interrupting capacity by voltage level
This breaker's interrupting capacity varies sharply with system voltage: 121 kA at 240 VAC, 75.6 kA at 415 VAC, 52.5 kA at 440 VAC, and 11.9 kA at both 500 VAC and 690 VAC. At the higher voltages the 11.9 kA figure is the same for both 500 V and 690 V — that is the ceiling for this frame size on those voltage levels. For a 480 V panel (common in North America) the 52.5 kA rating at 440 V is the closest published benchmark; the actual 480 V value is not listed here, so verify against the full device manual if your available fault current approaches that range.
Panel fit and mounting
The 3VA1125-4EF42-0AA0 measures 70 mm deep, 101.6 mm wide, and 130 mm high. The 101.6 mm width (4 inches) is the standard MCCB footprint for a 4-pole frame in this SENTRON series. The front face carries an IP40 protection class.
Power loss and operating range
Maximum power dissipation is 8.5 W at rated load. Operating ambient spans -25 °C to 70 °C; storage range is -40 °C to 80 °C. The rated insulation voltage is 800 V.