A self-consistent energy-independent non-local model pseudopotential theory has been developed for ternary alloys of simple metals for the first time. For K-Rb-Cs alloys, the partial structure factors are obtained by a solution of the standard Percus-Yevick equations for a ternary mixture of hard spheres. These partial structure factors are applied to calculate the electrical resistivities in the full concentration range of the alloy using the Ziman theory. Both the structure factors and the pseudopotential calculated form factors have been shown to be concentration sensitive. It has been shown that the electrical resistivities of the binary liquid alloys, such as K-Rb or K-Cs which exhibit nearly ideal structural behaviour, can be predicted to be in reasonable agreement with the experimental data. For ternary alloys, the calculated electrical resistivities vary smoothly with the concentration of each constituent, follow a well defined pattern in continuity and form a so-called 'electrical resistivity surface'. The results suggest that both the second-order non-local pseudopotential perturbation theory and the Ziman formalism are quite applicable in the prediction of the electrical resistivities of the multi-component alloys.