1. Field of the Invention This invention relates generally to computer systems and more particularly to a method and apparatus for providing electrical shielding for an AC power plug. 2. Description of the Related Art In a typical AC outlet, AC mains voltages are input through a wall socket into an outlet receptacle. Each prong of the outlet receptacle has some electrical resistance. However, the prongs are typically spaced at a very short distance, providing only very little resistance. Therefore, the voltages applied to the prongs can vary at the outlet receptacle, causing one of the prongs to be at a higher voltage than another prong. For instance, a receptacle with two prongs will have a cathode on one side of the centerline and an anode on the other side of the centerline, with the centerline being between the cathode and the anode. In some plug configurations, a filter capacitor is coupled between the two prongs, removing the power (i.e., voltage) at the centerline. In such configurations, the centerline is the cathode and the ground is the anode. This leads to the potential for the centerline to have a lower voltage than the anode. When different outlets are connected to a power source, this imbalance in voltages can cause a problem known as “mains voltage imbalance,” or “safety hazard.” Mains voltage imbalance results from the current flowing from cathode to anode in a vertical direction, opposite that of the flow of current in a horizontal direction. For instance, some plugs have a second “spacer” or “spark plug” prong that is connected to a ground. When the power is turned on, the ground and the power prong are at different voltages. The difference in voltages is manifested as a small spark that can start a fire. This effect is called ground shock. In order to reduce the chance of a fire and to create a more uniform mains voltage, mains voltage imbalance limits are commonly included in a new electrical receptacle. Mains voltage imbalance limits are intended to have voltage imbalances in the range of 500 milliVolts (mV) or less. In the past, mains voltage imbalance limits have been incorporated into a new outlet by adding components to the electrical receptacle to effectively remove the imbalances. The added components can include a fuse, spark suppression, or an electronic phase control circuit. However