How to choose circuit breaker?

By：Nader Updated：August 11,2020 11:26AM

How to choose circuit breaker?

The circuit breaker has only a short-circuit protection, the control circuit may be used for protection fuse.

In fact, this is too much trouble speaking, sub-forums, the main role of parts used, but also the load

give you a map, all clear.

Circuit breaker type	Current type and range	Protection features			Main purpose
Distribution line protection	Exchange 200~400A	Select Type B	Secondary protection	Instantaneous	Main power switch
				Short delay
			Three-stage protection	Instantaneous
				Short delay
				Long time delay
		Non-selection Type A	Current limiting type	Long time delay	Branch near-end switch and branch end switch
			General type	Instantaneous
	DC 600~6000A	Fast type	With polarity, without polarity		Protect thyristor AC equipment
		General type	Long delay, instantaneous		Protect general DC equipment
Motor protection	Exchange 60~600A	Start directly	General type	Momentary action of overcurrent release Multiple (8 ~ 15) In	Protect the cage motor

			Current limiting type	Momentary action of overcurrent release Multiple 12In	To protect the cage motor, it can also be installed near the transformer end
		Indirect start	Momentary action of overcurrent release Multiple (3 ~ 8) In		Protection of cage motors and winding motors
Lighting and wire protection	Exchange 5~50A	Load long delay, instantaneous disconnection			Stand-alone, in addition to being used for lighting, it can also be used for secondary circuits of electrical equipment and models in living buildings
Leakage protection	Communication 20~200A	15mA, 30mA, 50mA, 75mA, 100mA, breaking within 0.1s			Ensure the safety of life and prevent fires caused by leakage
Special purpose	AC or DC	Generally only instantaneous action is required			Such as de-excitation switch