Abstract: A method for the prevention of arcing in a spark erosion process, in which a pulse-shaped voltage is applied across an electrode and a workpiece, which voltage has a first predetermined value during a variable ignition retarding period determined by the process parameters, and on the termination of this ignition retarding period a discharge takes place between the electrode and the workpiece, resulting in the flow of a pulse-shaped current and in the voltage dropping in absolute sense to a second value determined by the process. The method comprises the additional steps of determining whether the voltage pulse satisfies a predetermined criterion and discontinuing voltage pulses failing to satisfy this criterion.