Abstract--This paper presents a channel model suitable for multiwire overhead medium voltage lines. This model, incorporating ground admittance, is more appropriate at higher frequencies than predicted by Carson's model of 1926. The proposed model is further used to evaluate the multipath channel impulse response and associated capacity limit in sample power distribution grids for applications in broadband over power lines communications. For a sample grid model, comparison is made to the capacity value predicted based on the Carson's model, and it is demonstrated that the older model underestimates the potential of the overhead lines for broadband transmissions, significantly.