Abstract: The invention provides control of an electric load receiving power from a grid. The frequency of the grid is detected and used to determine a stress level on the grid. A high frequency detection is indicative of too little a load for the electrical power being supplied to the grid and, therefore, a low stress condition. A high stress condition may exist if there is too much load for the power being supplied to the grid. Adjustment of the power consumption of the load is prevented if the high and/or low stress states is determined. If a critical high or low stress condition is determined, the load is either prevented from consuming power completely or the load is set to a maximum power consumption state, respectively. The benefits of the invention are increased if the device is combined with a load controller which operates to control power consumption based on grid frequency and a variable, which, for the particular load, is to be kept within controlled limits.