Ideally, the power company provides this from the service entry as it enters the house and is distributed with the power cables throughout the house. Without proper grounding, all devices that consume electricity have the potential to shock and even kill if there was a pre-existing condition such as a heart attack. First, check if the house outlets have grounding with a multimeter if possible by connecting one probe into the powered side and the other into the ground side. If the house outlet is grounded it should read half the amount of total voltage you have in the house. For a 220 volt system, it should read anywhere from 100 to 110 volts.