What this MCCB is and where it fits
The Siemens 3VA2340-5HL32-0DA0 is a SENTRON molded case circuit breaker (MCCB) sized for 400 A continuous current in a 3-pole configuration, designed for line protection in distribution panels. Its 187 kA interrupting rating at 240 V tells you it can handle high-fault scenarios typical of industrial service entrances or large motor control centers — that's the rating that governs selectivity coordination downstream. The built-in undervoltage release (UVR) means the breaker trips automatically when supply voltage drops below a threshold, a common requirement for safety circuits or machinery that must not restart unattended after a brownout.
Thermal derating and real-world current
Rated 400 A continuous at ambient temperatures up to 50 °C, the 3VA2340-5HL32-0DA0 holds its full ampacity without derating in most panel environments. Above 50 °C it steps down: 385 A at 55 °C, 370 A at 60 °C, 355 A at 65 °C, and 340 A at 70 °C. If your enclosure runs hot — say, a packed switchboard near a furnace line — factor that 340 A floor at 70 °C into your load calculation. Maximum power loss is 98.5 W, so ventilation matters in a sealed cabinet.
Breaking capacity across voltage levels
Interrupting performance varies sharply with system voltage: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 7.5 kA at 690 V. The 690 V figure is the weak point — if your installation runs at that level, verify the available fault current stays under 7.5 kA, or step up to a higher-rated frame. For 480 V北美 panels, the 121 kA at 440 V is a conservative proxy; actual 480 V performance would be slightly lower but still substantial.