A cable pulling pulley, also known as a sheave or running block, is a crucial tool used to guide and support a cable or conductor during a pull. Its primary purpose is to reduce friction and change the direction of the pulling force. By guiding the cable along its route, a pulley prevents the cable from dragging on the ground or rubbing against obstacles. This is essential for protecting the cable's outer jacket from abrasion and for significantly reducing the tension required to complete the pull, which in turn reduces stress on the pulling equipment and the cable itself.