Earth leakage breaker having built-in trip module type circuit breaker

Abstract

Proposed is an earth leakage breaker having a built-in trip module type circuit breaker, which is installed at a line between a power supply and a load and has a trip module configured to cut the line off, the earth leakage breaker including: a CT installed on the line and configured to monitor an instantaneous current; and a control circuit unit comprising: an operation module configured to receive an instantaneous current sensed by the CT, to measure an instantaneous current value per unit time, and to calculate a slope of the instantaneous current per unit time; a determination module configured to determine a case as an overload state, the case having the slope exceeding an overcurrent determination value A, and to cause an overload state determination signal to be output; and an output module configured to output a trip module actuation signal according to the overload state determination signal of the determination module and to cut off the line, and accordingly, the earth leakage breaker causes the trip module to be actuated according to an instantaneous current slope.