Operational Characteristics of Earth-Leakage Circuit Breakers in the Presence of Low-Current Series Arcs

This study examines the operational characteristics of earth-leakage circuit breakers (ELCBs) in response to low-current series arcs. Five 20 A ELCBs were selected as experimental specimens, and HFIX wires were used to apply currents of 5 A, 10 A, 15 A, and 20 A below the rated current as well as 30 A, representing overcurrent, to investigate how ELCBs respond to series arc generation. The results showed that at 15 A and 20 A, which correspond to series arc conditions below the rated current, a rapid temperature increase occurred due to arc energy. Sawdust ignited within 135-150 s and 30-35 s, respectively, indicating a significant fire risk. However, the ELCBs did not activate since the load remained below the rated current. When an overcurrent of 30 A was applied, some ELCBs were triggered and tripped under normal conditions. However, in the presence of a series arc fault, the fire risk was particularly high, as sawdust ignited before the ELCBs activated, or they operated only after the fire had already started. These findings highlight the limitations of ELCBs in detecting series arcs, emphasizing the need for additional protective devices such as arc-fault circuit interrupters (AFCIs).