T-Posts are steel posts that in cross section expose a T shape in their construction. On the flat side of the post are studs that help you attach fence wire by using clips or insulators to hold electrified wire in place. T-Posts are used in low-tension fence applications.-Posts are used to support the fence wire along the distance between the wooden corners. Use a sledgehammer or post driver to drive a T-Post into the ground every 10 to 25 feet along the fence line starting from either end.