The application of an immune algorithm for the optimal switching search problem to achieve loss minimisation and loading balance among feeders and main transformers is presented. This algorithm prevents the possibility of stagnation in the iteration process and achieves fast convergence for global optimisation. The efficiency of the immune algorithm to solve the problem is verified by comparing the computing time of the conventional binary integer programming for decision making of the switching operation. An interactive best-compromise method is also applied to solve the multiobjective distribution-feeder reconfiguration. Quantitative measures can be supplied to aid the decision-making process. A Taipower distribution system with 18 feeders is selected for computer simulation to demonstrate the effectiveness of the proposed methodology for solving the optimal-switching operation of distribution systems to minimise the power loss and simultaneously enhance the loading balance.