It is used when a given installation under the standard working conditions cannot be grounded. In the case when the thunderbolt strikes into the installation the electric current of the thunderbolt has to be directed to the earth. Under standard conditions the magneto provides an insulating gap between the installation and the earth. There occurs a short-circuiting inside the magneto in the case of a lightning discharge, which ensures the flow of the electric current of the thunderbolt to the earth. Among other applications, it is used for the protection of antenna masts.