A method estimating a series or parallel nature and a location of an arc in a photovoltaic device, operating under direct current, including N (N=1 or N>1) strings of photovoltaic modules, connected to a charge device having a capacitive behaviour for the modules, the method including: a) detecting, at terminals of each of the modules of each string, evolution of voltage over time, during formation of an electric arc; b) identifying the modules at the terminals of which a voltage variation occurs between a first zone with stable voltage and a second zone with stable voltage for a duration of at least 5 μs, which immediately follows the voltage variation, and identifying the sign of each voltage variation; c) estimating the series or parallel nature and the location of the arc in the photovoltaic device.