Potential Transformer has a small output and have high accuracy. It is used with voltmeters, wattmeters, watt-hour meters, relays and other controls. Several instruments may be connected to the same transformer if their sum does not exceed the burden for which the transformer is designed. It is a special type of transformer that allows meters to take readings from electrical service connections with higher voltage than the meter is normally capable of handling without at potential transformer. They are designed for relatively low power but high accuracy and high reliability. They are used to measure and monitor the voltage of high voltage lines by transforming the line voltage to some easily measurable value, often 100V.