Siemens 3VA2450-7MN32-0BC0 — 500 A MCCB for Motor Protection
The Siemens SENTRON 3VA2450-7MN32-0BC0 is a 3-pole molded case circuit breaker (MCCB) rated 500 A at 40 °C, designed specifically for motor protection. It carries a maximum interrupting capacity of 330 kA at 240 V, 242 kA at 415 V, and 187 kA at 500 V — figures that give you headroom for high-fault installations like large motor feeders or transformer secondaries. The breaker includes an undervoltage release (UVR) and phase failure detection, both of which are critical for protecting motor loads against single-phasing or loss of control voltage.
Thermal Derating and Power Loss
The 500 A rating holds flat from 40 °C up to 50 °C, then derates linearly: 495 A at 55 °C, 490 A at 60 °C, 485 A at 65 °C, and 480 A at 70 °C. Maximum power loss is 101.5 W. For a panel builder, that means the breaker can sit in a warm enclosure without losing much capacity, but the 101.5 W dissipation needs to be factored into the enclosure's thermal budget — especially if the breaker is grouped with other high-current devices.
Dimensions and Panel Fit
The breaker measures 248 mm high, 138 mm wide, and 110 mm deep. The 138 mm width is the standard 3-pole MCCB footprint for this frame size — it will fit existing SENTRON mounting bases and busbar systems without modification. The 110 mm depth leaves clearance for rear-connected busbars or cable lugs in a typical switchboard.
Built-in Auxiliary and Release Options
This variant ships with two auxiliary switches (HQ type) and an undervoltage release (UVR) factory-installed. The UVR trips the breaker when control voltage drops below a set threshold — a standard requirement for motor starters that need to drop out on power loss. The auxiliary switches can be wired into a PLC or status indication circuit. No communication function is included; this is a standalone protection device.