Abstract: In a gas-filled overvoltage diverter, the electrodes are coated with an activation compound and are located on an insulator. At least one axial ignition strip is disposed on the inner surface of the insulator. The inner surface of the insulator also has an ionization source in the form of a coating of an electroluminescent material. The coating is connected to both electrodes and may take the form of a strip. Alternatively, the coating may cover the entire inner surface of the insulator. The alkali halide and/or alkaline-earth halide coating material may also contain dielectric or ferro-electric crystals.