The invention relates to a plug-in combination of appliances for protecting against overvoltages, said combination of appliances comprising: a socket-type lower part and at least one plug-in module, which can both receive overvoltage protection elements; contact elements and contact counter elements that are respectively arranged in the lower part and in the plug-in module; and complementary guide rails or guide grooves for inserting or pushing-on and fixing the respective plug-in module. According to the invention, functionally separated, mechanical catch or snap-in elements act between the respective plug-in module and the socket-type lower part independently of the forces which hold together the contact elements and the contact counter elements in a positively fixed and/or non-positively fixed manner when the plug-in module is in use. The catch or snap-in function can be cancelled without any mechanical auxiliary means when the respective plug-in module is to be replaced.