NXMD is mainly applicable to the AC 50/60Hz distribution line which has no frequent operations with a rated operational voltage of 400V and below, and a rated current from 125A to 1000A to provide overload and short-circuit protection to the line and equipment. Meanwhile, it has the function of electric meter control and can automatically disconnect the circuit breaker when the user has overdue bills. After it’s manually switched on wh en there are overdue bills, it can automatically switch off, to prevent electricity theft.