Method for connecting an electrical device, which comprises a tubular metal casing and contact segments (11, 12) of electrical conductors of the electrical device extending from its front end, to contact segments (21, 22) of electrical conductors (23, 24) of a connection cable, having the steps: - Providing an insulation element (40, 140), composed of an electrically insulating material, which has inlets (41, 42, 43, 44, 141, 142, 143, 144) for the insertion of at least one contact segment (11, 12) of an electrical conductor of the electrical device and of at least one contact segment (21, 22) of an electrical conductor (23, 24) of the connection cable, wherein the inlets (41, 42 43, 44, 141, 142, 143, 144) transition into each other in a contact region (45, 48, 145, 148) and which has at least one opening (46, 47, 49, 50, 146, 147, 149, 150) that provides further access to the contact region (45, 48, 145, 148), - inserting at least one contact segment (11, 12) of an electrical conductor of the electrical device and at least one contact segment (21, 22) of an electrical conductor (23, 24) of the connection cable into the inlets (41, 42, 43, 44, 141, 142, 143, 144) of the insulation element such that the respective contact segments (11, 21, 12, 22) extend into the contact region (45, 48, 145, 148), or overlap each other there, or adjoin each other there, and - establishing an electrical connection (51, 52) between the respective contact segments (11, 21, 12, 22), wherein this electrical connection (51, 52) is established through the opening (46, 47, 49, 50, 146, 147, 149, 150) that provides the further access to the contact region (45, 48, 145, 148), characterized in that a sleeve is pushed onto the connection cable and, after the electrical connection (51, 52) is established, is positioned to entirely or partially enclose the insulation element (40, 140). - Providing an insulation element (40, 140), composed of an electrically insulating material, which has inlets (41, 42, 43, 44, 141, 142, 143, 144) for the insertion of at least one contact segment (11, 12) of an electrical conductor of the electrical device and of at least one contact segment (21, 22) of an electrical conductor (23, 24) of the connection cable, wherein the inlets (41, 42 43, 44, 141, 142, 143, 144) transition into each other in a contact region (45, 48, 145, 148) and which has at least one opening (46, 47, 49, 50, 146, 147, 149, 150) that provides further access to the contact region (45, 48, 145, 148), - inserting at least one contact segment (11, 12) of an electrical conductor of the electrical device and at least one contact segment (21, 22) of an electrical conductor (23, 24) of the connection cable into the inlets (41, 42, 43, 44, 141, 142, 143, 144) of the insulation element such that the respective contact segments (11, 21, 12, 22) extend into the contact region (45, 48, 145, 148), or overlap each other there, or adjoin each other there, and - establishing an electrical connection (51, 52) between the respective contact segments (11, 21, 12, 22), wherein this electrical connection (51, 52) is established through the opening (46, 47, 49, 50, 146, 147, 149, 150) that provides the further access to the contact region (45, 48, 145, 148), characterized in that a sleeve is pushed onto the connection cable and, after the electrical connection (51, 52) is established, is positioned to entirely or partially enclose the insulation element (40, 140).