Page 46 - 2020 Interconnect Innovations eBook

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Screw Connections
These types of terminal blocks have been around the longest and are probably the most familiar. In fact, familiarity is one of their biggest advantages, as people tend to favor solutions that they have already used successfully. However, while screw-actuation terminal blocks are reasonably reliable, they’re not without their issues. For instance, screw- actuation terminal blocks rely on manufacturer-specified torque values in order to achieve and maintain proper connections. If the initial connection is too tight or too loose (i.e., over or under torqued), it can fail as a result. Screw connections are also not the most resistant to extreme weather conditions or vibration, which makes them prone to unreliability. In addition, the need for a tool (especially if you consider the technically appropriate torque screwdriver) and continual maintenance (in the form of retightening) can make screw-connection terminal blocks less than optimal. Newer connection technologies eliminate these concerns.
Push-In Connections with Tool Operation
Push-in terminal blocks are designed to allow solid or ferruled wires to be inserted into the block and establish connections without the need for any tools. The only time this actuation style requires insertion tools is for the connection of stranded or flexible wires, or for the subsequent removal of any conductor type.
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» WAGO’s TOPJOB S Rail-Mount Terminal Blocks are available with levers, push-buttons, and operating slots to provide optimal solutions for any wiring application.
Terminal blocks with push-in connection technology enable quick and easy wiring connections, whether the connection is made to a circuit board or in a control cabinet. They are good for small spaces and provide ways to ensure that users’ hands are free to wire the application. By inserting the tool into the operating slot, where it is held firmly in place, users are able to introduce wires before removing the tool to complete the operation. Wires can also be disconnected from the block in the same way. One final advantage is their economic value. Tool-operated push-in terminal blocks are inexpensive and reliable and utilize a spring clamp to maintain connections without the use of a screw.