Abstract: An insulator is provided for supporting an electric wire or ribbon associated with an electric fence, including a pair of brackets that may be positioned about any location or elevation on a rectangular fence post or rail and then snappably secured thereto. The all plastic insulator is thus mounted without penetrating the post or rail with any hardware such as nails, bolts or staples. This assembly also allows easy removal of an insulator without damaging the post. The bracket assembly is also adjustable to accommodate a plurality of rectangular post sizes. Rubberized pads inside the bracket assembly provide friction and grip to more securely maintain the desired position. The bracket assembly integrally includes an elongated insulator body having a wire support holder attached thereto for easily receiving an electric wire or ribbon while substantially preventing accidental removal of the same.