How to choose a suitable safety circuit breaker?

A safety circuit breaker is a device that helps to protect circuits and equipment from damage due to overloads or short circuits. They are an important part of any electrical system and can help to prevent fires and other accidents. If you are considering installing a safety circuit breaker in your home or business, be sure to consult with a qualified electrician first to ensure that it is the right choice for your specific needs.

• How to choose a suitable safety circuit breaker?

• What is the selection principle of safety circuit breaker?

• What is the workflow of safety circuit breaker?

How to choose a suitable safety circuit breaker?

1) Determine the type and protection form of the circuit breaker according to the protection requirements of the line and determine the choice of frame type, device type or current limiting type, etc.

2) The rated voltage UN of the safety circuit breaker should be equal to or greater than the rated voltage of the protected line.

3) The rated voltage of the safety circuit breaker undervoltage release should be equal to the rated voltage of the protected line.

4) The rated current of the safety circuit breaker and the rated current of the overcurrent release should be greater than or equal to the calculated current of the protected line.

5) The ultimate breaking capacity of the safety circuit breaker should be greater than the effective value of the maximum short-circuit current of the line.

6) The protection characteristics of the upper and lower circuit breakers in the distribution line should be coordinated, and the protection characteristics of the lower level should be located below the upper level protection characteristics and not intersect.

7) The long-delay tripping current of the circuit breaker should be less than the allowable continuous current of the wire.

What is the selection principle of safety circuit breaker?

(1) The long-time delay current setting value

(2) Instantaneous setting current. For circuit breakers that protect cage-type motors, the instantaneous setting current is 8 to 15 times the rated current of the motor, and its value depends on the type, capacity and starting conditions of the protected motor. For circuit breakers that protect wound rotor motors, the instantaneous setting circuit is 3 to 6 times the rated current of the motor.

What is the workflow of safety circuit breaker?

When short-circuited, the magnetic field generated by the large current (generally 10 to 12 times) overcomes the reaction force spring, the release pulls the operating mechanism to act, and the switch trips instantaneously. When overloaded, the current becomes larger, the heat generation is intensified, and the bimetal sheet is deformed to a certain extent to push the mechanism to move (the greater the current, the shorter the action time). Now there is an electronic type safety circuit breaker, which uses transformers to collect the current of each phase and compares it with the set value. When the current is abnormal, the microprocessor sends a signal to make the electronic tripper drive the operating mechanism to move.

JIELI Electrical has been based in the low-voltage circuit breaker industry for nearly 20 years. Committed to the research and development, production, and supply chain management of MCB, RCCB and related supporting products.