A method for calibrating a communication and measuring circuit of an AC outlet (28, 38, 48) via one of an optical signal and Radio Frequency Identification, RFID, signal generated in close proximity by a loader (100, 110, 120, 130, 140, 150, 312), said circuit being configured for measuring a power consumed by a load (58, 70, 500) and including a first socket (28, 38, 48), a terminal configured for applying said power to said load and at least one of a first optoport and a first RFID antenna accessed through the front of said first socket; said loader including a communication and calibrated circuit (2, 3, 4) configured for measuring said power consumed by said load and a standard load (300, 310, 311), said communication and calibrated circuit including a first plug (9, 19, 49) complementary to said first socket, a second socket (8, 18) and at least one of a second optoport and a second RFID antenna accessed through the front of said first plug; said communication and measuring circuit being programmed to calculate the power consumed by said load for transmitting a derived first value and receiving a calibration command, said communication and calibrated circuit (2, 3, 4) being programmed to calculate said power consumed by said load and derive a calibrated value, receive said first value, compare said first value with said calibrated value and communicate said calibration command for calibrating said communication and measuring circuit when said first value and said calibrated value do not match, said method comprising the steps of: a. attaching said first plug to said first socket; b. attaching said load to said second socket; c. measuring the power consumed via said AC outlet; d. transmitting said derived first value to said loader via one of said first optoport and said first RFID antenna; e. measuring the power consumed via said loader; f. comparing the received said first value with said calibrated value; and g. communicating at least one calibrate command with said AC outlet via one of said second optoport and said second RFID antenna when said first value and said calibrated value do not match. said loader including a communication and calibrated circuit (2, 3, 4) configured for measuring said power consumed by said load and a standard load (300, 310, 311), said communication and calibrated circuit including a first plug (9, 19, 49) complementary to said first socket, a second socket (8, 18) and at least one of a second optoport and a second RFID antenna accessed through the front of said first plug; said communication and measuring circuit being programmed to calculate the power consumed by said load for transmitting a derived first value and receiving a calibration command, said communication and calibrated circuit (2, 3, 4) being programmed to calculate said power consumed by said load and derive a calibrated value, receive said first value, compare said first value with said calibrated value and communicate said calibration command for calibrating said communication and measuring circuit when said first value and said calibrated value do not match, said method comprising the steps of: a. attaching said first plug to said first socket; b. attaching said load to said second socket; c. measuring the power consumed via said AC outlet; d. transmitting said derived first value to said loader via one of said first optoport and said first RFID antenna; e. measuring the power consumed via said loader; f. comparing the received said first value with said calibrated value; and g. communicating at least one calibrate command with said AC outlet via one of said second optoport and said second RFID antenna when said first value and said calibrated value do not match. a. attaching said first plug to said first socket; b. attaching said load to said second socket; c. measuring the power consumed via said AC outlet; d. transmitting said derived first value to said loader via one of said first optoport and said first RFID antenna; e. measuring the power consumed via said loader; f. comparing the received said first value with said calibrated value; and g. communicating at least one calibrate command with said AC outlet via one of said second optoport and said second RFID antenna when said first value and said calibrated value do not match.