... power systems,such as TT, IT, TN-S, TN-C, TN-C-S. It protects the electric network shocked by the ... 5AConductor sectionBY10-40/4-150Maximum single line: 1.5mm2Main Structure and Operating PrincipleIn three-phase four- line system , three phase lines and one zero line ... the protector connected to L line should be in series connect with a fuse. The appearance and installation dimension refer to the ...