Abstract:California’s aggressive electric vehicle (EV) policies may generate a large burden of EV charging load on the electric distribution system. In this study, we investigate the development of overloading in the distribution networks, using feeder-level capacity and load data from the grid, and a travel demand model together with empirical EV charging data. We select twelve representative areas across the territories of the three major investor-owned utilities in California. Overloading conditions are highly diverse within our case studies. Three out of the twelve areas that we examine have frequent overloading over 50% of the time starting between 2028 and 2040. Four areas will be challenged by intense overloading, where EV charging load can reach up to 500% of the remaining capacity headroom. Our findings indicate a need for infrastructure upgrade in some parts of the Californian distribution system within the next two decades. However, the spatial heterogeneity in our results suggest a need for large-scale case-by-case analysis.