The condition of being electrically separated from other structures.
Galvanic cathodic protection systems are designed to protect specific tanks or specific piping runs from corrosion. A system designed to protect a particular tank will not be totally effective if it seeks also to protect piping connected to the tank. (The piping may require its own cathodic protection system.)
For this reason, tanks and piping are separated from other structures through use of electrical isolation devices. These include nylon bushings and special flanges. The presence of such isolation devices provides assurance that a cathodic protection system designed for particular structures effectively protects only the structures for which it is intended.