This paper presents the most representative solutions used in the detection of unintentional electric islands in electrical distribution grid. In addition, it analyzes the adoption of these methods by equipment manufacturers, both in distributed resources based on power inverters and in protections and systems for monitoring the state of the grid. This work also compares the applicable regulations in some European countries. Keywords: Anti-islanding, unintentional electric island, electrical distribution grids, detection methods, inverters.