As Plug-in Hybrid Vehicles (PHEVs) take a greater share in the personal automobile market, their penetration levels may bring potential challenges to electric utility especially at the distribution level. This paper examines the impact of charging PHEVs on a distribution transformer under different charging scenarios. The simulation results indicate that at the PHEV penetration level of interest, new load peaks will be created, which in some cases may exceed the distribution transformer capacity. In order to keep the PHEVs from causing harmful new peaks, thus making the system more secure and efficient, several PHEV charging profiles are analyzed and some possible demand management solutions, including PHEV stagger charge and household load control, are explored.