An electric series circuit with plural loads such as light bulbs connected in series and plural solid state switching devices, with each switching device connected in parallel with one of the loads. Each switching device conducts current when the load that it is connected in parallel with does not conduct current because the load is burned out. The solid state switching means may be any device with a breakthrough voltage which is high enough that it does not conduct when all of the loads conduct current normally. When one of the loads is burned out, that load does not conduct current and the entire line voltage appears across the switching means in parallel with the burned out load. The switching means breaks down. Accordingly, the switching means conducts current and current flows to the remaining loads. Accordingly, the remaining light bulbs in a string of light bulbs continue to light. The burned out load may be immediately detected and replaced. The switching means may be a sidac. Alternatively, a combination of an SCR and a zener diode controlling the gate of the SCR are also disclosed as the switching means. A diac may replace the zener diode.