Siemens SENTRON 3VA1150-5EF36-0DA0 — 50 A MCCB with Undervoltage Release
The Siemens SENTRON 3VA1150-5EF36-0DA0 is a 3-pole molded case circuit breaker (MCCB) rated 50 A at 40 °C, designed for line protection in industrial power distribution. Its headline breaking capacity is 187 kA at 240 V AC — that is the short-circuit current it can safely interrupt at that voltage level, which determines the available fault current the panel's upstream gear must be rated to supply. The breaker carries an 800 V rated insulation voltage, so it is suitable for 480 V and 600 V class systems as well. This variant includes an integrated undervoltage release (UVR) — the auxiliary release trips the breaker when supply voltage drops below a set threshold, which is standard for motor control centers or safety circuits where a loss of control voltage must open the main disconnect. The UVR is factory-fitted; no field kit required. Rated current is flat at 50 A from 40 °C through 50 °C ambient, then derates to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. That means in a warm enclosure you lose about 1 A per 5 °C above 50 °C — plan your continuous load margin accordingly.
Breaking Capacity by Voltage — SCCR Planning
The 3VA1150-5EF36-0DA0 delivers 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. The steep drop above 440 V is typical for this frame size — the arc extinction physics limit the interrupting rating at higher line voltages. For a 480 V panel, the relevant figure is the 440 V rating (75.6 kA), since the breaker's performance at 480 V is bounded by the next-lower tested voltage point. If your available fault current at 480 V exceeds 75.6 kA, you need a larger frame or a current-limiting upstream device.
Panel Fit and Dimensions
The breaker measures 130 mm high, 76.2 mm wide (3 in), and 70 mm deep. That 3-inch width per pole is standard for this frame class — it occupies three 1-inch module spaces on a DIN rail or panel-mount footprint. The depth of 70 mm (2.76 in) leaves clearance behind the panel for wiring and the UVR coil connections.
Power Loss and Thermal Management
Maximum power dissipation is 17.1 W at rated load. In a sealed enclosure with multiple breakers ganged, that heat adds up — account for it in the cabinet's thermal budget to stay within the 70 °C maximum operating ambient.