A photovoltaic system comprises a plurality of photovoltaic modules which are electrically connected to a string or to multiple parallel-connected strings and form a PV generator. The first string end forms the negative pole of the photovoltaic generator, and the second string end forms the positive pole. A voltage reduction device is provided with the aid of which the potential of the negative pole is lowered to ground. Advantages with regard to the insulation class of the connecting cable used are also provided.