A low-tension (low-voltage) Air Circuit Breaker (ACB) is a heavy-duty, reusable electrical protection device designed to safeguard low-voltage power systems (typically up to 690V) from damaging overcurrents and short circuits. It uses compressed or atmospheric air to effectively cool and extinguish the electric arc created when the circuit is interrupted, which enhances safety in industrial and commercial settings where fire hazards are a concern. With high current ratings often exceeding 800A and adjustable, modern microprocessor-based trip units, ACBs offer robust and customizable protection for main power distribution systems, large motors, transformers, and generators, and they are built for durability and easy maintenance through features like draw-out designs.