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23 April 2020
With almost half of all system failures caused by poorly connected conductors, there has never been a better time to re-examine the advantages and performance guarantees screwless conductor connection technology solutions offer. Clive Humphrey highlights the installation, performance and time saving benefits of going screwless for conductor connections in terminal blocks.
A critical component of any panel building system – connection within terminal blocks – is a fundamental element for safe, reliable and high-performing electrical solutions for panel projects.
Often perceived as an insignificant part of the overall system, poor or failing connections can have serious repercussions, leading to unwanted downtime, lost production and costly problems. Yet, despite these issues screw-based methods are still commonly specified and used for conductor connection because of habit and tradition, and sometimes because outdated standards dictate they are used.
However, screw connections are prone to operational problems, and can be challenged by a proven and high performing alternative solution – screwless cage connection technology.
Screwless technology offers a range of benefits, which when combined, become a powerful advocate for its specification. They include ease of installation, vibration resistance and time saving.
Ease of installation
Users are often left with a dilemma when it comes to the practical aspects of screw connection installation. While they must turn the screw to tighten and loosen the clamp, they need to question the level of torque applied (if they follow the manufacturer’s instructions on this) and their ability to undertake this. Final connection success can depend on variables such as the strength of the person and the torque screwdriver being used, if indeed a torque screwdriver is used, and not just a standard screwdriver. Screwless technology removes such variables.
There is no longer a requirement for a torque screwdriver, as users only need an operating tool to open the clamp. Depending on the type of terminal block, some even have a spring design which allows solid or ferruled conductors to be pushed directly into the terminal. So, the possibility of damage through over tightening or a loose connection is eliminated. Manufactured from stainless steel, the spring mechanism cannot be over stretched because of the stops built into the moulding of the terminal block.
Safely clamped & vibration resistant
It is an accepted practice for screw connections to put two wires into one clamp to common them together. Whether the wires are twisted together or inserted separately, there is no guarantee that both conductors will be properly clamped. Most of the screwless type DIN rail mount and panel mount terminals, as well as junction box connectors, are available in two, three and four conductor versions which individually clamp each conductor safely and securely to offer real peace of mind.
As it is a spring, if screwless cage technology is used in an environment subjected to vibration, then it will always keep the conductor clamped securely against the current bar in the terminal block. This is a big advantage for applications placed in aggressive operating environments, as well as a means of dealing with any shock and vibration problems resulting from the transportation of panels to their final location.
In addition, routine maintenance of screw connections is required to make sure they have not loosened over time. However, the clamping force of a screwless cage technology connection will not reduce, regardless of how long it has been installed or the temperature (within a wide range) in which it must operate.
Finally, our own in-depth product testing has shown WAGO’s screwless cage technology can save up to 264% of the time required to install wiring within terminal blocks, when compared with traditional screw connection terminals. This is primarily because of screwless technology’s ease of use. Fitting accessories such as a jumper to common terminals is simply a case of pushing it firmly into place. There are no link bars to fit or a myriad of screws to tighten.
Clive Humphrey is Product Manager – Interconnection at WAGO