A system for sensing electrical power usage in an electrical power infrastructure of a structure. The system can include a sensing device configured to be attached to a panel of the circuit breaker box overlying at least part of the one or more main electrical power supply lines. The system also can include a calibration device configured to be electrically coupled to the electrical power infrastructure of the structure. The system further can include one or more processing modules configured to receive one or more output signals from the sensing device. The sensing device can be devoid of being electrically or physically coupled to the one or more main electrical power supply lines or the electrical power infrastructure when the sensing device is attached to the panel. Other embodiments are provided.