All-around safe power-on socket

The utility model discloses an all-around safe power-on socket connected with a U, V, W, N, PE three-phase five-wire system AC electric circuit. The socket comprises an AC contactor KT, a short circuit/overvoltage/under-voltage/overcurrent protection circuit QF, a leakage measurement and control circuit CT, and a socket unit ET. The socket has protection functions of short circuit, overload, under-voltage, overcurrent, and electric leakage. The whole circuit has very high distress breaking capacity, electric shock arc light spark is small, and the circuit eliminates fear of students initially try when the circuit is powered on, and greatly improve security and protecting force in experimental training. The safe power-on socket does not need to connect with a fuse, and troubles of changing a fusing core or a fuse wire after an abnormal accident occurs to a general protector. The socket saves resources and protects safely and reliably. Interfaces of the safe power-on socket unit ET are in two kinds of three-phase four-hole and single-phase three-hole. The single-phase three-hole or the three-phase four-hole interface also can be used to plug with a power board, and the protection effect function is the same, thereby providing convenience to expand connection range of an experiment plug board.