1250A ACB Circuit Breaker Unit

Module Feature

1250A is the frame rated current specification of air circuit breaker.

It is widely used for main incoming, bus tie and heavy load branch protection in low voltage power distribution cabinet. It can be equipped with electronic trip unit for adjustable LSI protection curve, supports draw-out or fixed installation structure. Many mainstream brands provide this specification ACB for industrial and commercial power distribution system.

Working principle

Current transformer samples three-phase current signal and transmits to electronic trip unit.

When overload, short circuit or earth fault is detected, the trip unit releases mechanical mechanism to open main contacts and extinguish fault current through arc chute. It supports electrical parameter measurement and optional communication function for remote monitoring.

Onboard components

Main contact assembly, arc extinguish chamber, current transformer, electronic trip controller, operating mechanism, terminal block.

LED indicators

Front LEDs indicate power ready, closing status, overload alarm and protection trip.

Hardware self‑diagnosis

Trip unit continuously monitors CT failure, controller anomaly and trip coil fault, and records fault event.

Programming software

Manufacturer dedicated configuration software, used for protection curve setting and fault log export.

Electrical & Process Parameters

Model:1250A Brand:General Device type:Air circuit breaker Rated current:1250A Voltage:400/690V AC Function:Overload, short circuit and earth fault protection for low voltage distribution

Mechanical & Structure

Mounting:Fixed or draw-out installation inside switchgear

Protection class:IP20

Housing:Metal frame with arc chute assembly

Environmental

Operating temperature:-5℃ ~ +40℃

Storage temperature:-40℃ ~ +85℃

Ambient humidity:5~95% non‑condensing

Certification:CE, IEC60947-2

Status:Standard power distribution spare

Installation

Install breaker in switch compartment and connect main busbar.

Check three-phase wiring before energizing, set protection parameters and test closing/tripping action.

Interface

Main busbar terminal, secondary control terminal block, trip and closing coil terminal.

Diagnostic

Fail to close: Energy storage incomplete, interlock locked, undervoltage coil damaged.

Unplanned trip: Overload, short circuit or earth fault on downstream load.

Abnormal heating: Insufficient busbar torque, main contact ablation.

Product Brief

1250A air circuit breaker, frame specification ACB for low voltage main distribution protection.