to another terminal e g terminal 253 or terminal 252 from the original terminal e g terminal 252 or terminal 253 supposedly at present the terminal 261 is being connected to terminal 262 on the said hand switch 26 and by the time while control unit 23 would like to turn on the said electrical appliance 27 it will have to connect the terminal 251 with terminal 252 whereas if the terminal 261 is being connected to terminal 263 on the said hand switch 26 and by the time while control unit 23 would like to turn on the electrical appliance 27 it will have to connect the terminal 251 with terminal 253 instead whereby to operate the overall system correctly it is very important for the control unit 23 to find out the actual connection status of terminal 261 fixed on the said hand switch 26 for this particular problem it can be easily resolved while control unit 23 is able to utilize the function provided by the detecting unit 24 whereat the said detecting unit 24 is being cascaded to both ends of the said electrical appliance 27 and whereby the detecting unit 24 is able to determine the actual connection status at the terminal 261 fixed on the hand switch 26 by measuring the electrical voltage at each end of the said electrical appliance 27 and then it will deliver the detection result back to the said control unit 23 whereby the control unit 23 will react upon receiving relevant detection results upon the occurrence of a malfunction in the automatic switch 25 which makes.