Why is isolation even used? Isolation is a means of preventing DC or uncontrolled transient current from flowing between two communicating points and, in general, is used in two situations: one, where there is a potential for voltage surges that may damage equipment or even harm humans; and second, where interconnections involve large ground potential differences and disruptive ground loops. In both cases, isolation is used to tolerate or protect from hazardous voltages, yet allows for data or power flow between the two points.