METHOD FOR WATERPROOFING ELECTRIC WIRE CONNECTING PORTION AND SHEET FOR WATERPROOFING THE SAME

PURPOSE:To excellently fill a clearance between electric wire connection portions with a melted and softened material by thermally melting and softening a sheet-like thermally softening material with application of heat to a layer wound around the electric wire connection portion, and causing a thermally foamable layer to foam so as to form a partition wall. CONSTITUTION:In the case where an electric wire branch connection portion is waterproofed by the use of a sheet for waterproofing an electric wire connection portion, the sheet is wound around the electric wire connection portion with a sheet-like heat material 41 facing inward. After the sheet for waterproofing the electric wire connection portion is wound around the electric wire branch connection portion, the wound layer is heated and the sheet-like softened material 41 is thermally melted and softened, resulting in foaming of a thermal foamable layer 42. The melted and softened material of the material 41 is filled in a clearance between electric wires while being pressurized in the inner diameter direction due to foaming of the layer 42 between the material 1 and a sheet-like supporting member 43. The foamable material of the material 41 serves as a partition wall with respect to flowing of the melted and softened material so that the clearance inside of the electric wire connection portion is filled with the melted and softened material.