When a user sets a 4-week energy limit, a socket’s oneday quota actually is calculated by the ELC module. If the energy controller is now in its ELC mode, the ELC module will control a socket’s one-day energy limit based on the fact that today is a weekday or weekend. When the energy consumption of a day exceeds the quota, if the socket is now inits AC mode, the ELC module sends a control signal to AC module to turn off the corresponding socket. But if the socket is now in its UC mode, the ELC module will send a warning signal to UC module to alert the user.