Basic Protection Switchgear: The most common protective device in low-voltage power distribution systems is the circuit breaker, which automatically cuts off current when an overload or short circuit occurs. Similar to household air switches, industrial-grade circuit breakers can withstand higher currents and have stronger breaking capacities. Another common device is the fuse, which provides protection by melting a fusible element; it is relatively inexpensive but requires replacement.
Operating and Control Switchgear: Load switches combine switching and protection functions, suitable for frequent operation scenarios. Combination switches achieve multi-circuit control through modular design and are commonly found in distribution cabinets. Contactors remotely control circuits using electromagnetic principles and can be used with thermal relays to form motor starters. This type of equipment emphasizes operational reliability and mechanical lifespan.
Safety Isolation Switchgear: Disconnecting switches are used to create a visible disconnect point during maintenance; their characteristic is the visible contact gap. Knife switches have a simple structure but weaker protection and are mostly used at the incoming line of distribution boxes. Disconnecting switches with fuses combine isolation and protection functions and are widely used in small power distribution systems. Safety Tip: Always ensure the circuit is de-energized before performing isolation operations.