Low voltage ACB

What is a Low Voltage ACB (Air Circuit Breaker)?

A low voltage ACB (Air Circuit Breaker) is a large breaker used to interrupt electrical current in low-voltage systems (up to 1,000V). Its primary function is as the "main switch" (Main Incoming) for large distribution boards (MDBs) in factories or high-rise buildings.

Its key features include strength, durability, and a high capacity to handle electrical current (from 800A up to 6,300A), which exceeds that of standard household breakers.

Key Components of Low Voltage ACB (Air Circuit Breaker)

The ACB has a more complex structure than sub-breakers (MCBs) and includes the following main components:

• Arc Chute (Arc Suppression Chamber): Metal plates stacked in layers to draw arcs into the chamber for extinguishing and cooling.
• Mechanism (Operating Mechanism): Typically uses a spring-loaded system (Spring Charged) to ensure quick and precise switching, which can be manual or motorized.
• Trip Unit (Trip Device): An intelligent electronic unit that allows detailed settings for tripping (such as Long Time Delay, Short Time Delay, Instantaneous), ensuring coordination with sub-breakers.

Installation Types of Low Voltage ACB (Air Circuit Breaker)

There are two main types:

• Fixed Type: Permanently mounted to the cabinet, harder to maintain and repair but cheaper.
• Draw-out Type (Most Popular): Allows the breaker to be "drawn" or "pushed out" from its cradle without disconnecting rear wiring, making maintenance and replacement much easier when needed.