Welded plastic attachment subassembly

A weldable moldular subassembly for enabling branch pipe means to be connected by welding to a main pipe formed of moldable plastic material, said subassembly comprising a pair of arcuate attachment members formed of moldable plastic material, each having a concave inner surface, the inner surface of each of said attachment members extending between a pair of longitudinal edges thereof, branch pipe means affixed to at least one of said attachment members, hinge means pivotally connecting said attachmemt members along one of the longitudinal edges of each of said attachment members with the longitudinal edge of the other of said attachment members to enable said subassembly to be placed around a main pipe to which said subassembly is to be welded, and a flexible rectangular heating wire mat having electrical wire means adapted to have electric current pass therethrough to weld said subassembly to said main pipe, said wire mat having a pair of generally parallel longitudinal sides with one of said longitudinal sides being connected along the inner surface of one of said attachment members at a point intermediate the longitudinal edges thereof, said connected longitudinal side extending general parallel to the longitudinal edges of the inner surface to which it is connected, whereby said attachment members may be placed to surround said main pipe with said wire mat interposed therebetween to effect welding together of said attachment members and said main pipe by passage of electrical current through said wire mat.