Glossary · Electrical engineering and control panels
Galvanic isolation
Also known as: Electrical isolation, Galvanic separation
German: Galvanische Trennung
In electrical engineering, galvanic isolation is the separation of two circuits so that no direct conductive path exists between them, while signals or energy are still transferred, for example by transformers, optocouplers or capacitive couplers.
- Control panels
In one sentence
Galvanic isolation separates circuits with no conductive path between them while still transferring signals or energy.
Example
Isolated analog input modules prevent a ground potential difference between the tank farm and the control room from distorting the level measurement.
How it applies
- Engineering: Galvanic isolation breaks Ground loop paths, protects electronics from potential differences and is part of protection concepts such as SELV and PELV, where the isolation must meet specified requirements. Isolated I/O modules, signal isolators and isolated power supplies are common solutions.
- Maintenance: Replacing an isolated module with a non-isolated one can reintroduce noise or damage; parts lists should specify the isolation.
- Documentation: State in data sheets and circuit diagrams which circuits are isolated from which, and the rated isolation voltage.
Galvanic isolation vs. energy isolation
Galvanic isolation is a design property of circuits. Energy isolation is the safe-work practice of disconnecting and securing energy sources before maintenance. A galvanically isolated circuit is not isolated in the lockout/tagout sense.