1. Electronic molded-case circuit breaker rated limit short-circuit breaking capacity Icu: The circuit breaker has two breaking capacity index values: the rated limit short-circuit breaking capacity Icu and the rated short-circuit breaking capacity Ics. As a characteristic parameter, Ics is not only a simple consideration of the breaking capacity of the circuit breaker, but also a durability index—in other words, it ensures normal operation after multiple short-circuit faults.
2. Overcurrent protection and breaking capability of electronic molded-case circuit breaker: When the circuit breaker experiences a short-circuit, the contacts will open rapidly to interrupt the current, which is equivalent to a sudden increase in circuit impedance, thereby limiting the fault current magnitude. The shorter the breaking time, the closer Ics is to Icu, and the better the overcurrent protection performance. This also significantly reduces the electromagnetic, electrodynamic, and thermal effects caused by short-circuit current on the circuit breaker and electrical equipment, extending the service life of the circuit breaker.
3. Electronic molded-case circuit breaker short-circuit protection: Short-circuit protection refers to instantaneous tripping. It is essential to adjust the protection setting value promptly after load changes to avoid a setting that is too low (causing frequent trips affecting power quality) or too high (failing to protect the circuit and equipment adequately).
4. Long-time delay protection: This refers to protection against overload currents exceeding equipment limits, which could cause overheating. The protection device delays tripping for a specified duration, as overloads involve heat accumulation and do not require immediate action. This protection is ineffective against short-term overcurrents.
5. Protective function of electronic molded-case circuit breaker: The residual-current protection ensures that leakage current after tripping does not endanger personnel or equipment. After multiple short-circuit trips, the switch characteristics may degrade, increasing leakage current. For humans, leakage currents below 30mA are considered safe. In harsh environments, leakage currents exceeding 300mA for over 2 hours may degrade insulation, cause ground faults, and lead to fires.