Screw connections have been in use for over forty years and enjoy the highest level of usage in the market. They remain popular due to their ease of use and versatility and their capability to accept solid, stranded, or ferruled wires. Screw connections are further broken down into three varieties. The first uses a leaf spring that descends to retain the wire when the screw is tightened. This construction offers an economical solution that provides an excellent choice for applications where space is at a premium. Clamping yoke connections, also known as cage clamps, are the most widely used because of their advantages in performance and reliability. They differ from the leaf spring style in that the retention feature rises into position from below. As the screw is tightened, the conductor is trapped between the clamping yoke and the current bar. This configuration provides the highest connection pressure and vibration resistance of the screw connection family. The Top style connection was designed for applications where the most compact solution is required. Tightening the screw actuates a cam which retains the conductor as it moves into position. This unique configuration results in a low profile package in addition to providing wire entry and screw access on the same side. All screw connections share the obvious advantage of being intuitive to use; tighten the screw and the wire is held in place, loosen the screw and the wire can be removed. However, this advantage can become a liability in that a tool is required for service and that the screw can potentially be over tightened or not tightened enough for proper wire retention.