To provide electrical conductivity from one rubber gasket pipe joint to another for the purpose of thawing frozen water mains, some specifiers require that Ductile iron (DI) pipe be furnished with a device that provides such conductivity.

Serrated Bronze Wedges can be provided for electrical thawing: two per joint, for 3-inch through 12-inch pipe; four for larger diameter pipe. Each wedge is driven into the opening between the plain end and the bell until snug. When four wedges are used, they are inserted side by side, in pairs.