Abstract: An arrangement for forced triggering a spark gap at a voltage below self-ignition voltage, which spark gap is divided into at least two sub spark gaps arranged in series, whereby voltage division components are connected in parallel with the sub spark gaps for effecting voltage division between the sub spark gaps. In order to obtain a forced triggering arrangement which is simple and reliable in operation, an element which is controlled to adopt a high-impedance or low-impedance state is arranged in series with the voltage division components, whereby the element, when adopting the high-impedance state, changes the voltage division between all the spark gaps so that one of the two series connected spark gaps arranged in parallel therewith is ignited.