Barbed wire Again there are two grades available and the same situation is applicable as for plain fence wire in terms of soft versus high tensile. Barbed wire should not be placed on the fence as the top wire as the breaking strain out of all wires is the lowest. If you chose to use this product always place a plain fence wire on top of the fence followed by the barbed product. Particular care should be taken when handling this product. The kinds including Heavy Galvanised High Tensile Barbed Wire, Standard Galvanised Iowa Barbed Wire.