Power electronics research group at the University of Waikato is involved with the development of non-traditional applications of supercapacitors, and among them, the patented technique SCASA is a surge protector device (SPD) that is designed to absorb the differential mode (DM) transient surges. But, considering the severity of lightning related surges, the necessity for a more versatile SPD incorporating both differential mode (DM) and common mode (CM) protection is identified. This paper summarizes the proposed methodology for a versatile dual-mode surge protector including the step by step design of circuit topologies and standard testing procedures. The operation of surge simulators, and the generation of repeated surge hits are discussed under the experimental phase. Laplace transforms and numerical integration methods are used in the theoretical analysis of circuit operations. The novel aspect of this research is the inclusion of supercapacitors; hence, their ability to absorb high voltage transients and surges is distinguished as an important fundamental characteristic when compared with electrolytic capacitors.