The objective of the work presented here is to estimate the characteristics of the power balance, i.e. the power and the surface power density that the electric arc brings to Ag-SnO 2 electrodes. This work is first based on an experimental study carried out using an IR camera with which we measured the temperature in a zone close to the area impacted by the arc, but not flashed by it. In a second step, the temperature distributions obtained are compared with the results of a numerical model of the electrode heating. The model input parameters are the power P and the surface power density Q. Solving this inverse problem thus makes it possible to estimate values of P and Q leading to measured and calculated heating (temperature distribution) that are as similar as possible. Such a method has been applied for Ag-SnO 2 cathodes and anodes and for various intensities of the arc current in a range 80-200 A.