Closed Circuit PLC system for large capacity load

PURPOSE: A closed circuit power line communication system for mass loads is provided to control current in communication using a switch control unit. CONSTITUTION: A switch control unit(120) disconnects a second switch unit when communication is not executed. The switch control unit disconnects the second switch unit when the communication is executed using a power line. The switch control unit outputs a switching signal for the predetermined communication signal to a first switch unit. The switching signal for the predetermined communication signal includes the switching signal which disconnects the first switch unit after the switching signal is a zero-cross power wave. [Reference numerals] (110) Key input unit; (111) Communication unit; (120) Switch control unit; (210) Power supply unit; (220) Signal processing unit; (230) Load control unit