What is maximum discharge current of a circuit breaker
The maximum discharge current of a circuit breaker, also known as the "short-circuit current" or "peak let-through current", is the maximum current that a circuit breaker is designed to interrupt or clear in the event of a short circuit or fault.
The maximum discharge current of a circuit breaker is typically specified by the manufacturer and is usually expressed in amperes (A). It is an important parameter that determines the circuit breaker's ability to safely interrupt a fault current and prevent damage to the equipment and personnel.
The maximum discharge current of a circuit breaker is influenced by several factors, including:
- The type and rating of the circuit breaker: Different types of circuit breakers, such as air-break, oil-break, or vacuum-break, have different maximum discharge currents.
- The voltage rating of the circuit breaker: Higher voltage-rated circuit breakers typically have higher maximum discharge currents.
- The fault current duration: The longer the fault current persists, the higher the maximum discharge current that the circuit breaker must be able to interrupt.
- The type of fault: The maximum discharge current required to interrupt a fault depends on the type of fault, such as a single-phase or three-phase fault.
Typical maximum discharge currents for different types of circuit breakers are:
- Air-break circuit breakers: 10,000 to 50,000 A
- Oil-break circuit breakers: 50,000 to 100,000 A
- Vacuum-break circuit breakers: 100,000 to 200,000 A
- High-voltage circuit breakers (e.g., 35 kV and above): 200,000 to 500,000 A or more
It's important to note that the maximum discharge current of a circuit breaker should not be exceeded, as this can cause damage to the breaker or the equipment it is protecting.