Fixing a hot wire and a ground wire that are reversed is as easy as unscrewing and switching the wires on the receptacle and screwing them tight again. Diagnose the error visually by looking behind the outlet or by inserting a three-light voltage tester into the outlet and using it. Sometimes, the error is up or downstream of the outlet, which requires more work to detect.
Hot and ground wires that are reversed can be dangerous, because the switch that is meant to break the hot wire's connection does not break the ground wire when it is hot. Electricity may still be inside a plugged-in device, causing a greater chance of electrical shock upon handling the item. If the ground wire discharges electricity onto the ground on which a person stands while he touches a hot ground wire, he also completes the circuit and sustains a shock.
A voltage meter that indicates a hot ground reverse error may actually detect an open neutral wire. This type of error can be corrected by finding the neutral wire and attaching it to the appropriate screw in the receptacle. Another method of correcting the error is to find the break in the wire somewhere else along the circuit.