Selection Principles for Circuit Breaker

A circuit breaker is a device that controls the flow of electric current, mainly used for the protection of circuits and equipment. When there is a fault such as overload, short circuit, or under voltage in the circuit, the circuit breaker can quickly cut off the power supply to protect the safety of the circuit, load, and related equipment. Circuit breaker is widely used in mechanical and electrical equipment and circuits, but the choice of circuit breaker protection characteristics is different depending on the ability of the protected object to withstand overload currents. Therefore, it is very important to choose the appropriate circuit breaker. Circuit breakers can be divided into distribution circuit breaker, motor protection circuit breaker, and household protection circuit breaker according to their usage. This article introduces how to choose the suitable circuit breaker based on their protection characteristics. Also, we recommend our related product 40 amp single phase breaker, and if you are interested, please contact us for more information.

Selection of distribution circuit breaker

Distribution circuit breaker is generally used in low-voltage power grids for distributing electrical energy, including the main power supply circuit breaker and branch circuit breaker. When selecting these types of circuit breaker, the following principles should be particularly noted: the line's allowable current carrying capacity should not be less than the long-delayed action current setting value of the circuit breaker. If wires and cables are used, the long-delayed action current setting value of the circuit breaker can be selected as 80% of the current carrying capacity of the wires and cables. The starting time of the motor with the maximum starting current in the line is not greater than three times the long-delayed action current setting value's return time. Futina has quality products for sale , and you can have a look.

Selection of motor protection circuit breaker

Electric motors have two characteristics: First, the starting current is usually several times the rated current; second, they have certain overload capacity. Therefore, when selecting circuit breaker to protect electric motors, it is necessary to pay attention to these two characteristics of electric motors. In order to ensure the reliable operation of the motor, the following points should be noted when selecting circuit breaker: the long-delayed action current setting value of the circuit breaker should be determined based on the rated current of the motor; the actual starting time of the motor is six times the long-delayed action current setting value's return time. The instantaneous action current setting value of the circuit breaker: for cage-type electric motors, it should be 8-15 times the rated current of the release; for wound-type electric motors, it should be 3-6 times the rated current of the release.

Selection of household protection circuit breaker

In household power supply, circuit breaker is usually used as the main power protection switch or branch line protection switch. When a short circuit or overload occurs in the line or household appliances, the circuit breaker can automatically trip and cut off the power supply to effectively protect these devices from damage and minimize the scope of accidents. In households, single-pole circuit breaker are generally used for branch protection, and two-pole circuit breaker is used for main power protection. The rated current capacity of the circuit breaker is very important in households because if the rated current of the circuit breaker is too large, the circuit breaker cannot trip and cut off the power supply when a short circuit or overload occurs in the line or household appliances. If the selected value is too small, the circuit breaker may trip frequently, resulting in unnecessary power outages, which affect normal life and cause unnecessary trouble.