SENTRON 3VM1225-4ED42-0AA0 — 250 A MCCB, Line Protection, TM210 Trip
Breaking capacity is rated by system voltage: 121 kA at 240 V AC, 76 kA at 415 V AC, 53 kA at 440 V AC, and 17 kA at 500 V AC. These figures cover high-fault utility feeds and transformer secondaries — the 121 kA at 240 V is typical for large LV switchboards where the available fault current is substantial. The 3VM1225-4ED42-0AA0 is a 4-pole unit with no undervoltage release, no communication function, no ground-fault monitoring, and no N-conductor protection. It is a straightforward thermal-magnetic breaker — no auxiliaries, no shunt trip, no voltage-triggered accessories. The front face carries an IP40 protection rating, suitable for enclosed panel mounting.
Current Derating and Thermal Management
The breaker is rated at a full 250 A from 40 °C through 50 °C ambient. Above that, the TM210 trip unit begins to derate: 243.3 A at 55 °C, 236.5 A at 60 °C, 229.8 A at 65 °C, and 223 A at 70 °C. For a panel OEM wireman, this means the breaker can be installed in a warm enclosure — up to 50 °C — without losing any ampacity. Above 50 °C, the derating curve is linear enough to calculate the effective rating for the actual ambient. Maximum power loss is 57 W. This is the heat the breaker dissipates at full rated current; it feeds into the enclosure thermal calculation. The storage temperature range is -40 °C to 80 °C, and the operating ambient range is -25 °C to 70 °C — the storage limit governs handling and warehousing, not running conditions.
Physical Fit and Panel Integration
Dimensions are 140 mm wide, 158 mm high, and 70 mm deep. The 140 mm width is standard for a 4-pole MCCB in the SENTRON 3VM frame — it occupies four 35 mm DIN-rail module spaces. The 70 mm depth is shallow enough to fit most 200 mm deep enclosures without crowding the gland plate or busbar system. Rated insulation voltage (Ui) is 800 V, and the maximum rated operational voltage is 690 V AC or 500 V DC. The breaker is designed for AC systems up to 690 V line-to-line, which covers 400 V, 480 V, and 600 V class networks. The DC rating of 500 V makes it usable in some DC distribution applications, though the breaking capacity in DC systems must be verified against the 3VA manual.