Abstract: A safety switch having first and second elements intended to be mounted on components of a safety enclosure that are moveable relative to one another. The first and second elements are in a predetermined relative position adjacent each other when the enclosure is in a closed condition and spaced apart when the enclosure is in an open condition. A source of magnetic flux is mounted on one element and a magnetically operable switch is mounted on the other element. The magnetically operable switch is arranged so as to be switched by the magnetic flux generated by the source when the elements are moved adjacent to each other. A pair of tuned circuits are mounted one in each of the elements, and a switching circuit is connected to one of the tuned circuits. The switching circuit is arranged so as to be switched when the elements are moved adjacent to each other.