Solar Cell Tabbing, Interconnect Wire and Tinned Copper Flat Wire for Solar Cell Modules. Solar Cell Tabbing or Interconnect Wire are primarily produced from a tin or tin alloy coated copper flat wire*. Ulbrich has been producing conductive materials for the photovoltaic industry since 1992, accumulating years of expertise that is applied to each and every order. A critical feature of Tabbing and Interconnect is lower yield strength and higher elongation.