4000AMP Circuit Breaker Unit

Module Feature

4000AMP is 4000 Ampere rated large frame low voltage air circuit breaker, commonly corresponding to Schneider MasterPact NW40, ABB Emax2, Siemens 3WL series frame.

It is designed for main incoming, bus tie and large power feeder application of heavy-load distribution system. It supports motor spring charging, electrical closing and tripping, and can be equipped with electronic trip unit for selective protection. It has high breaking capacity to clear severe short-circuit fault, and supports time-stamped fault recording and SCADA communication expansion. It is widely stocked as maintenance spare for petrochemical, power station and data center low voltage switchgear cabinet.

Working principle

Built-in CT sensors sample three-phase current signals and send to electronic protection trip unit.

Trip unit runs overload, short delay, instantaneous short circuit and earth fault protection algorithm. When hazardous fault is detected, trip mechanism releases instantly to separate main contacts and isolate faulty circuit. Operation counter, fault waveform and event sequence records are stored inside the protection module for post-fault analysis.

Onboard components

Main contact group, arc quenching chamber, stored-energy spring mechanism, charge motor, closing/trip coil, current transformer set, auxiliary contact block, local operation handle, trip display unit and metal insulated frame.

LED indicators

Front LEDs indicate breaker ON/OFF state, spring charged, fault trip and communication alarm status.

Hardware self‑diagnosis

Built-in trip circuit supervision and power supply monitoring. Trip unit detects coil break, signal loss and internal hardware anomaly. Fault parameter setting and log reading depend on manufacturer matching commissioning software.

Programming software

Manufacturer dedicated protection configuration tool, used for protection curve setup, communication address, interlock logic and firmware upgrade.

Electrical & Process Parameters

Model:4000AMP Brand:Multi-brand compatible heavy-duty distribution spare Device type:4000A low voltage air circuit breaker Function:Overload, short circuit and earth fault protection for LV main power incoming and bus coupling circuit

Mechanical & Structure

Mounting:Switchgear cabinet fixed or withdrawable drawer mounting Protection class:IP30 front, IP20 terminal compartment Housing:Heavy-duty industrial reinforced breaker frame

Environmental

Operating temperature:-10℃ ~ +55℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing

Certification:CE, IEC 60947-2 Status:Original power distribution spare

Installation

Cut off upstream power supply before replacement.

Verify rated current, pole number and breaking grade, check primary busbar and secondary control wiring, test charge, close/trip action and protection function after commissioning.

Interface

Primary copper bar terminal, secondary screw terminal block for auxiliary contact, trip coil and communication FTA.

Diagnostic

Fail to close: Spring not charged, interlock signal missing or closing coil damaged. False protection trip: CT wiring error, protection curve improper setting or electrical interference. Communication offline: Bus termination resistance error, cable damage or address conflict.

Product Brief

4000AMP circuit breaker, 4000A large frame low voltage breaker spare for industrial substation main incoming switchgear cabinet replacement.