PIPE WITH EXPANDABLE DIAMETER FOR INSULATOR UNIT

PROBLEM TO BE SOLVED: To prevent a foreign material from entering a part between the inner circumferential part of an insulator unit and the outer circumferential face of a pipe with expandable diameter, when the diameter of the insulator unit is expanded in order to form the connection part of a power cable by using the insulator unit. SOLUTION: A pipe 1 with expandable diameter which is formed in a pipe shape by winding a leaf spring and whose outside diameter is variable is used. When an insulator unit is shipped, the pipe 1 is inserted in a clean room so as to be brought into close contact with the inner circumferential face of the insulator unit. In its execution, the inside diameter of the pipe 1 is expanded together with the insulator unit. Thereby, the inner circumferential face of the insulator unit is protected by the pipe 1 with expandable diameter up to its execution from its shipment, and it is possible to prevent a foreign material from entering.