There is provided a housing comprising an electrically powered device and electrical connecting means. The (electrical connecting means of the) housing fit an interface means of an electrical power supply. The housing is provided with magnetically activable switching means which in a passive isolation state are open. The magnetically activable switching means prevent an electric current from passing between the electrical connecting means and the electrically powered device. The interface means comprise magnetic activation means enable an electric current to pass between the electrical connecting means and the electrically powered device when the housing has been properly installed.
