Ryhmäkatkaisija

Ryhmäkatkaisija, often translated as circuit breaker, is an automatic electrical switch designed to protect an electrical circuit from damage caused by overcurrent or short circuit. It performs its protective function by interrupting current flow when it detects a fault. Unlike a fuse, which is a disposable device, a circuit breaker can be reset and used again after a fault has been cleared.

Circuit breakers are commonly found in residential, commercial, and industrial electrical systems. They are essential components for safety, preventing fires and damage to electrical equipment that can result from overloaded circuits or short circuits. The operation of a ryhmäkatkaisija relies on a mechanism that triggers its opening when an abnormal current is detected. Common tripping mechanisms include thermal, magnetic, or a combination of both.

A thermal trip mechanism uses a bimetallic strip that bends when heated by excess current, eventually actuating the switch. A magnetic trip mechanism uses an electromagnet that pulls on a lever to open the contacts when a sudden surge of current occurs, typical in a short circuit. The rating of a circuit breaker indicates the maximum current it can safely handle before tripping. Selecting the correct rating is crucial for effective protection.