The Siemens 3WT8121-6UN34-5BC2 is a SENTRON 3WT8 series Air Circuit Breaker (ACB) designed for high-capacity low-voltage power distribution systems. It is used for main incomer and feeder protection in industrial and commercial electrical networks, ensuring safety against overload, short-circuit, and earth fault conditions.
This model belongs to the 1250A, 3-pole withdrawable ACB range, engineered for heavy-duty applications like PCC panels, MCC panels, transformers, and generator systems.
• Siemens SENTRON 3WT8 series Air Circuit Breaker
• Part Number: 3WT8121-6UN34-5BC2
• 3 Pole configuration
• Rated current: 1250A
• Breaking capacity: 66kA @ 500V AC (series dependent, typically ETU37WT LSING family)
• Withdrawable (draw-out) type design for safe maintenance
• Advanced electronic protection unit: ETU37WT LSING
• Protection functions: Overload, Short circuit, Earth fault
• Motorized / manual spring charging operating mechanism
• Mechanical lockout + trip indication system
• Auxiliary contacts, shunt release options (variant dependent)
• IEC 60947-2 compliant
• High short-time withstand capability (industrial-grade performance)
| Parameter | Specification |
|---|---|
| Product Series | Siemens SENTRON 3WT8 |
| Part Number | 3WT8121-6UN34-5BC2 |
| Product Type | Air Circuit Breaker (ACB) |
| Number of Poles | 3 Pole |
| Rated Current | 1250A |
| Rated Voltage | Up to 500V AC |
| Breaking Capacity (Icu) | 66kA @ 500V AC |
| Protection Unit | ETU37WT LSING |
| Protection Functions | Overload, Short Circuit, Earth Fault |
| Type | Withdrawable / Draw-out |
| Frequency | 50/60 Hz |
| Mounting Type | Fixed base with draw-out mechanism |
| Standard | IEC 60947-2 |
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