The invention relates to a
circuit breaker with a grounding protection function and an electric leakage protection function. The
circuit breaker comprises the components of
four current transformers (CT1,CT2,CT3,CT4), one double-tap zero-sequence mutual
inductor (CTZ), a dial switch (S1), resistors (R1,R2), a button (S2) and an intelligent
tripping device (CE). Switching between different signals is realized through matching between the dial switch (S1) and the double-tap zero-sequence mutual
inductor (CTZ). After
data acquisition and conversion by the intelligent
tripping device (CE), protection is performed. Combination of the grounding protection function and the electric leakage protection function is realized. According to the
circuit breaker, free switching between the electric leakage protection function and the grounding protection function is realized through changing the position of the dial switch (S1), production cost of the circuit breaker and user cost are reduced. Furthermore the circuit breaker can satisfy a requirement of a power supply
system for selection from grounding protection and electric leakage protection.