C curve circuit breaker vs b curve circuit breaker

In the world of circuit breakers, the "C" and "B" curves refer to the tripping characteristics of the breaker. The main difference between a C curve and a B curve circuit breaker lies in their response to fault currents.

C Curve (Time-Delay Curve):

A C curve circuit breaker is designed to trip quickly (typically within 1-2 cycles) when a fault current exceeds a certain threshold. This is because the breaker is designed to respond rapidly to high-energy faults, such as those caused by a short circuit or a ground fault.

The C curve breaker has a relatively short arcing time, which means it can interrupt the fault current quickly, reducing the risk of damage to the equipment and minimizing the risk of fire.

B Curve (Inverse-Time Curve):

A B curve circuit breaker, on the other hand, is designed to trip more slowly (typically within 5-10 cycles) when a fault current exceeds a certain threshold. This is because the breaker is designed to respond to lower-energy faults, such as those caused by a overload or a partial short circuit.

The B curve breaker has a longer arcing time, which means it can interrupt the fault current more gradually, reducing the risk of damage to the equipment and minimizing the risk of fire.

Key differences:

  1. Tripping time: C curve breakers trip faster than B curve breakers.
  2. Fault current threshold: C curve breakers are designed to trip at higher fault currents, while B curve breakers are designed to trip at lower fault currents.
  3. Arcing time: C curve breakers have a shorter arcing time than B curve breakers.
  4. Application: C curve breakers are typically used in applications where high-energy faults are more likely to occur, such as in industrial power systems or in areas with high fault currents. B curve breakers are typically used in applications where lower-energy faults are more likely to occur, such as in residential or commercial power systems.

In summary, C curve circuit breakers are designed to respond quickly to high-energy faults, while B curve circuit breakers are designed to respond more slowly to lower-energy faults. The choice between a C curve and a B curve breaker depends on the specific application and the type of faults that are likely to occur.