What it is and what it does
The Siemens 3VA1080-4ED42-0JA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in industrial power distribution panels. It's a 4-pole unit rated at 80 A continuous current at 40 °C ambient, with a thermal-magnetic overcurrent release (TM210) for overload and short-circuit protection. The interrupting capacity hits 121 kA at 240 V AC — that's the fault current it can safely clear without welding contacts or venting plasma into the enclosure. The shunt trip release (STL) built into this variant allows remote tripping via a control voltage signal — useful for emergency-stop circuits or supervisory shutdown sequences. No undervoltage release is fitted, so the breaker stays latched on loss of control power unless the shunt trip is actively triggered.
Breaking capacity across voltage levels
This MCCB's short-circuit rating drops as line voltage rises: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. The steep drop above 440 V reflects the arc-energy physics in a compact frame — at 690 V the breaker still handles 11.9 kA, enough for most motor-control-center fault levels but not for high-capacity transformer secondaries at that voltage.
Thermal derating and panel integration
Rated current holds at 80 A from 40 °C through 50 °C ambient, then derates to 78 A at 55 °C, 77 A at 60 °C, 75 A at 65 °C, and 74 A at 70 °C. In a sealed, uncooled enclosure near other heat sources, expect to knock off 5–8 % from the nameplate for reliable long-term operation. The 70 mm depth and 101.6 mm width fit standard Siemens 3VA panel cutouts; the supplied basic switch (3VA10804ED420AA0) is the replaceable switching mechanism inside the molded case.