Abstract: When analyzing a system of conducting bodies interconnected by wires, the current expansion functions consist of three classes, body expansion functions, wire expansion functions and junction expansion functions. The integral term of electric field integral equation (EFIE) is the 3 D Green's function multiplied by the current expansion function or its divergence. With one singular kernel in the junction expansion function, there are two singular kernels in the singular integral term. As a result of change of variables in integrals, the singularity points are removed, and then the double integrals are reduced to integral of one variable. Therefore the remaining function is continuously differential and suited for numerical integrals. Sample computations are given to validate this method.