The present disclosure relates to a method for monitoring an on-board electrical system (200) of a vehicle having at least one distributor (207, 704) and a load (206) that are connected together via a cable (210, L21, H1). In one implementation, the method includes reading in a sequence of data for a number of parameters representing information about operation of the vehicle by a driver and/or about a state of the vehicle and/or a state of the driver and/or a driving environment; classifying the data as a normal value or an error value; and evaluating the data classified as an error value or a normal value. The normal values may lie within a state space separated from the error values by a discrimination limit. Evaluating the data classified as an error value may include determining if the data classified as an error value fulfils a criterion, and evaluating the data classified as a normal value may include statistically evaluating to determine a stochastic parameter and determining if the stochastic parameter exceeds a threshold value.