Abstract: A self-contained air gap spark arrester assembly is disclosed which may be constructed and tested prior to its incorporation into a fail-safe surge arrester assembly. The air gap spark arrester assembly comprises a rivet shaped electrode, on which are concentrically mounted an insulating ring, a ring electrode, and an insulating spacer ring. These elements are arranged so as to provide an air gap between the two electrodes, aproximately equal to the thickness of the spacer ring and shielded from particulate contamination. Due to the placement of the assembly's electrodes, it is particularly well suited for combination with gas tube arresters in metal canisters. In one embodiment the canister is of cylindrical form and houses a fusible alloy spacer, a cylindrical gas discharge tube, and the air gap spark arrester assembly.