High-Current Terminal Blocks: Powering the Future of Industry

Good Afternoon Umuju, 

Thank you for your feedback and for sharing your experiences, I’m glad that many of them are positive. I’d like to help you understand our high current terminals. 

The largest terminals in the WAGO range, the 285-1185 (DIN rail mount version), will clamp a solid, stranded or fine stranded wire up to 185mm² (350 kcmil). The force exerted on the wire within the cage by the clamping mechanism will not flatten or deform a solid wire of that size, however it will exert the force needed to clamp it securely, ensuring that there is no “hot spot”. The force is determined by the design of the mechanism and the size of the spring and cannot be influenced by the person making the connection. 

The conductor is installed or removed easily using a hex wrench which slots into the top of the terminal. To release a conductor, insert the tool then twist it in the direction of the arrow on the top of terminal to release the spring pressure. When the spring is fully open, press in the orange button on the side of the terminal to lock it open. The conductor can then be removed. There is no additional pressure exerted onto the conductor to remove it, in fact from the moment the tool is first turned, the pressure is released. The connection is both easy to operate and reliable. 

The lever on any WAGO terminal should not snap under normal use. Do you remember what type of terminal it was where you had this experience? 

The housing will not break on any WAGO terminal during connection or disconnection either. When using the WAGO tool operated terminal (the slot type), if the housing is being damaged it is because either the wrong tool is being used or too much force is being exerted. 

Yes, you are right, it is possible for connections to become loose over time, but not WAGO CAGE CLAMP, Push-In CAGE CLAMP or POWER CAGE CLAMP (as used in our 285 Series) type. The conductor is held in position with a spring rather than a screw so it cannot work loose, does not require maintenance and there is nothing to tighten. The clamp dynamically compensates for conductor deformation due to flow effects of the copper. The spring does not loose its ability to apply the required clamping force and does not require any adjustment at all. And the housing is designed to support the conductors and clamping mechanism for the full life of the terminal, in use and during connection and disconnection. As long as the terminal is stored, operated installed within the specified temperature ranges then it will not suffer any degradation. 

I hope that my comments have been helpful and that they have given you a better understanding of our terminals. I have Laboratory Test Reports that I can share with you that give more detailed information, please get in contact with us if you wanted to learn more 

I’ve had pretty good experiences with your products in low voltage applications, but some of the issues I’ve run into would be compounded by higher current loads. I am curious of the ways this technology can simplify installation and troubleshooting, but I would like to know if/how some of these concerns have been addressed.

The first concern would be if sufficient force can be applied to the wire when terminating  larger conductors such as a 350 kcmil. Typically, the amount of force necessary to ensure a solid connection will deform the wire and flatten it to the sidewall of the lug. In instances where sufficient force was not applied, the heat generated at the point of termination was enough to melt the insulation on the conductors back to the raceway and caused a short.

My second concern would be the method for installing or removing the conductors. If sufficient force is being applied to ensure a good connection, greater force would need to be applied to release the tension allowing the conductor to move. My past experience with DIN rail mounted connections has given me doubts as to the ease or reliability of the options available. In using lever type WAGO connectors, I have had the lever used snap on the first attempt to open the block for termination. On screw type mounts, the plastic housing will often try to twist or even break. The slot type releases have similar issues as the housings are affected by the force necessary to release the pressure on the termination. 

My final question would be of longevity. Over time, connections can become loose. Many companies have employed IR scanning of their equipment to map potential hot-spots and schedule maintenance. While this would require a shutdown, the only cost would be the manpower to tighten the lugs to spec and inspect the conductors for damage. In most cases, this can be accomplished at the time of the IR scan. If the pressure being applied is from a spring, I would be concerned how quickly the spring loses its ability to apply the required pressure and if this is adjustable, or would the full unit need to be replaced to be able to apply the appropriate amount of force. As most of the structure or the units are plastic, would they hold up to not only the force being applied to hold the conductors stable, but also to the force needed to install and remove the conductors? As plastics are exposed to different temperatures, they can become soft and/or brittle. When fluctuating between these states over time, the overall integrity degrades.

I do like the convenience that WAGO offers with their connections and have been impressed with the improvements I’ve seen, but the issues I have encountered with spring pressure wire connections have limited my willingness to use them in my trade. My largest concern is with the reliability of the connection over time, and I haven’t seen a method of connection that I trust with the higher current demands that require larger wire.