Earth leakage circuit breaker

1. A circuit breaker for overcurrent protection and earth leakage protection, comprising:

a zero-phase current transformer;

an earth leakage detection circuit;

a trip coil;

a sensitivity current-switch;

an action time switch;

an earth leakage test switch;

a circuit board having mounted thereon the earth leakage detection circuit, the sensitivity current-switch, the action time switch, and the earth leakage test switch;

an earth leakage trip unit case having installed therein the circuit board having thereon the earth leakage detection circuit, the sensitivity current-switch, the action time switch and the earth leakage test switch;

a main housing accommodating therein the earth leakage trip unit case, the zero-phase current transformer, and the trip coil; and

an open-close operation handle, wherein the circuit board and the trip coil are combined, and the earth leakage trip unit case is disposed beside the open-close operation handle;

wherein the earth leakage trip unit case comprises:

a lower case accommodating the trip coil;

an upper case disposed on the lower case and accommodating the circuit board; and

a cover disposed on the upper case,

wherein terminals of the circuit board, an end of the upper case and an end of the cover are extended adjacent to the zero-phase current transformer, and terminals of the zero-phase current transformer and the terminals of the circuit board are electrically connected.

2. The circuit breaker according to claim 1 , wherein the lower case, the upper case, and the cover are detachably engageable by a snap-fit mechanism.

3. The circuit breaker according to claim 1 , further comprising lead wires drawn out of the terminals of the circuit board and connected to the zero-phase current transformer.

4. The circuit breaker according to claim 1 , wherein the zero-phase current transformer is disposed adjacent to a load terminal of the main housing.