To provide a wiring instrument with a leakage detection function that can prevent an entire power failure due to breaking of a master earth leakage breaker from occurring, and a system.
The wiring instrument includes: a zero-phase-sequence current transformer 25 which has a leakage detection function, and is interposed between a master earth leakage breaker, connected to a commercial power source or private power generation power source and detecting a plurality of leakage currents to determine a leakage of electricity, and a load part so as to detect the leakage currents; a resistance 32 which performs voltage conversion of the output of the zero-phase-sequence current transformer 25; a low-pass filter 33 which receives a voltage signal of the resistance 32; a threshold determination part 34 which compares the output of the low-pass filter 33 with a threshold; a leakage determination part 35 which determines that there is a leakage of electricity when the output of the low-pass filter 33 exceeds the threshold for a time predetermined by the threshold determination part 34; and a making/breaking part which disconnects the master earth leakage breaker and load part from each other in response to the output of the leakage determination part 35. The predetermined time and threshold are set to a time and a level such that occurrence of the leakage of electricity can be detected with one pulse wave of the leakage current.
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Masataka Otani
Satoshi Sakurai