Miniatuurrelektriskaitselülitid

Miniatuurrelektriskaitselülitid, often abbreviated as MCBs, are electromechanical devices designed to protect electrical circuits from overcurrents, which can be caused by overloads or short circuits. They function by automatically interrupting the flow of current when an abnormal condition is detected, thereby preventing damage to wiring and electrical equipment, and reducing the risk of fire.

An MCB consists of several key components. A bimetallic strip is used to detect overloads, which cause a slow increase in current. As the bimetallic strip heats up, it bends and trips a mechanism, opening the circuit. For short circuits, which involve a rapid surge of current, an electromagnet is employed. The strong magnetic field generated by a short circuit pulls an armature, which also triggers the tripping mechanism. Once tripped, the MCB can be manually reset by flipping a lever, provided the fault has been cleared.

These devices are widely used in residential, commercial, and industrial applications as a replacement for older fuse systems. Their primary advantages include reusability, ease of resetting, and a clearer indication of the tripped circuit. MCBs are rated according to the amount of current they can safely interrupt and the type of tripping characteristics they possess, such as Type B, C, or D, which determine how quickly they respond to different levels of overcurrent. They are a fundamental component of modern electrical safety systems.