What is the difference between a frame circuit breaker and a molded case circuit breaker?

The application of circuit breakers in life is very extensive, but many people easily confuse rack circuit breakers and molded case circuit breakers when they are used. So, what is the difference between the two in function and application?

1. The appearance and installation dimensions of the two are different

First of all, in terms of appearance, the sizes of the two are different, the size and volume of the frame circuit breaker are larger, and the size and volume of the molded case circuit breaker are relatively small.

2. The protection functions of the two releases are different

The intelligent release of frame circuit breaker has protection function, measurement function, auxiliary function, special function and communication function. The protection functions include long delay protection, short delay protection, instantaneous protection, MCR protection, grounding protection, low voltage protection/alarm, overvoltage protection/alarm, voltage unbalance and phase loss protection/alarm, phase sequence protection, low voltage protection Frequency protection, high frequency protection, reverse power protection, voltage harmonic alarm, current harmonic alarm;
Measurement functions: current measurement, voltage measurement, power measurement, frequency measurement, energy measurement, harmonic measurement;
Auxiliary functions: pre-alarm, self-diagnosis function, fault history record function, test function;
Special functions: load monitoring, regional joint control, high and low temperature range;
Communication function: communication protocol function, etc.
Molded case circuit breakers mainly have long delay protection, short delay protection (ie overload protection) and instantaneous protection (ie short circuit protection). The intelligent release of the following frame circuit breaker: It can be seen that the protection function of the frame circuit breaker is more powerful than that of the plastic case.

3. The scope of application of the two is different

The rated current of the frame circuit breaker ranges from 400A to 6300A. It is mainly used in the power distribution network to distribute electric energy, protect lines and power equipment from overload, undervoltage, short circuit, single-phase grounding and other faults;
The rated current of the molded case circuit breaker is from 10 to 800A. It is used to protect the line and equipment when overload, short circuit and undervoltage occur in the distribution line. It can also provide overload and short circuit for infrequent starting of the motor. , Undervoltage protection.

4. Different types of use

The use category of molded case circuit breakers is usually Class A. Under short-circuit conditions, there is no artificial short-time delay for selective protection, so there is no short-time withstand current (Icw) value;
The use category of the frame circuit breaker is usually Class B. In the case of short circuit, the selective protection is artificially short-delayed (adjustable), so it has a short-time withstand current (Icw) value;
The above content is an introduction to the difference between frame circuit breakers and molded case circuit breakers. I hope that the above introduction can help friends when choosing circuit breakers in practical applications.