Importance

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Abstract

The present invention relates to a 3 phase electric leakage current circuit breaker with electric shock protection having a first function of detecting a leakage current and operating a circuit breaker to break an electric path if a leakage current exceeds a tolerance and a second function of detecting a leakage current every half cycle intervals of a power source, subtracting two leakage currents detected before and after a half cycle interval from each other as a vector calculus to compute a leakage current change, and operating a circuit breaker to break an electric path if the leakage current change exceeds a tolerance. The former case corresponds to protection against a normal leakage current which gradually increases, and an allowable leakage current is several hundreds of mA. The latter case is for protection against electric shock to a human body when a leakage current abruptly changes due to electric shock to a human body or the like, and an allowable leakage current is several tens of mA. Therefore, along the 3 phase electric path, the electric leakage current circuit breaker of the present invention may operate without any malfunction with respect to the normal leakage current change while protecting the human body from the electric shock.

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First Claim