Purpose: To show the relevance of a simple finite difference transmission line model for help in the design of safe cables in 1.5 T MRI’s using the multi-section cable approach. Methods: A two section wire will be studied as a function of the length of the two different sections. The result concerning the heating of the electrodes for a constant electrical field excitation along the wire as well as the estimation of the correction phase factor will be compared to full-wave simulation results. Such information allows estimation of the worst case heating of the cable in MRI taking into account the phase effects. Results: The transmission line predicts correctly the full-wave simulation results. The optimum length of the second section reduces by 37% the worst case heating at the electrode compared to the best case unique section wire. Conclusion: The multi-section cable design can reduce the heating of cables in MRI taking into account the phase effects. The finite difference transmission line model presented is a simple valuable tool to estimate the worst case heating of multi-section cables thus helping to optimize the design of such cables.