What Are The Differences between DC Circuit Breaker or AC MCB?


DC circuit breakers refer to circuit breakers used in DC power distribution systems. Generally applicable to solar photovoltaic power generation and power distribution systems, battery energy storage systems, new energy vehicle DC charging systems, etc.A system in which the input power supply terminal of the circuit breaker is DC current.


General DC circuit breakers include DC MCB (Miniature Circuit Breaker), DC MCCB (DC molded case circuit breaker), and RCCB (Residual Current Device).

DC miniature circuit breaker MCB is specially designed for direct current (DC) circuit applications and is used for over-current and short-circuit protection in electrical appliances or electrical equipment.

DC MCB and the AC MCB are same functions. but, the usage scenarios of AC MCB and DC MCB are different.

DC MCB mostly uses for direct current (DC) systems application, such as new energy, solar photovoltaic (PV) and Solar cell energy storage system. The voltage state of DC MCB is generally DC 12V-1500V.

The difference between AC MCB and DC MCB in physical parameters on products.

The AC MCB are marked as LOAD and LINE on products, and the DC circuit breaker symbol marked as positive (+), negative (-) signs and the direction of the current on products.

AC MCB.jpg

Can I use a ac circuit breaker for dc?

The signal of AC current is constantly changing its value for every second. The circuit breaker arc will be extinguished at 0 volts, and the circuit will be protected from big current.

But the signal of DC current is not alternating, it works in a constant state, and the voltage value will only change when the circuit is tripped or the circuit is reduced as a certain value.

Otherwise, the DC circuit will provide a constant voltage value for every second of a minute. Therefore, since there is no 0 volt point in the DC state, it does not suggest that use a AC circuit breaker for the DC state.


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