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Ensure correct pressing of cable lugs

Before we go into the details about connection technology, we would like to provide you with some tips for the process of compression, so that your connections are safe and long lasting.

For clean results


Before actually pressing, make sure the components are clean. This means that the conductors are metallically clean through brushing and aluminium cables are checked for any visible oxidation layer that needs to be removed. In general, you should make sure that no traces of metal remain on the conductor, otherwise contact corrosion may occur.


With the use of a good wire stripper, you can strip the cables clean. Make sure not to damage the conductor and the length of the stripped part should be about ten percent longer than the insertion size of the cable lug or connector. This is because the cable lug or connection extends by about ten percent during the pressing. So don’t scrimp on the stripping!

Also make sure that the press inserts are not damaged or soiled. Their profile should show a metallic sheen.

This is how pressing is made easy
Once the connectors and conductors have been prepared, the actual pressing can begin.
Cable lugs can only be professionally and cleanly processed without over- or under-pressing, if you use suitable tools. Therefore, the selection of cable lug and crimping tool should be within a system: the same manufacturer for the cable lug, connector and tool. Compatible tool components and expert pressing prevent increased contact resistance and resulting temperature increases, which can cause fires in the worst case.

Crimping on a cable lug always starts on the connection side and works towards the cable side. On a connector (splice), however, the first crimp is in the centre. Otherwise, the material cannot lengthen and it can lead to the formation of cracks.

For example, the number of pressings required for crimped cable lugs according to DIN 46235 is indicated by markings on the cable lug and connector. For tubular cable lugs, the number of pressings can be found in the catalogue.

Make sure that the pressing process is fully completed. A complete pressing process is important because the required compression of the pressed material is only achieved at the end of the pressing phase. This is the only way correct pressing can be ensured.

Mechanical or hydraulic presses?

The pressing tool is the key element of each pressing operation. Regardless of whether it is performed hydraulically or with muscle power: When pressing the cable lug, the degree and type of deformation are determined by the tool or the contact-specific wear parts of the press. Only tools that are perfectly matched to the contact allow a high quality connection.

Whether a mechanical press or an electro-hydraulic press is the right choice for you depends on how you plan to use it. Compact mechanical crimping tools are suitable for small to medium cross sections. For larger cross sections, on the other hand, you are usually better off using a hydraulic tool with changeable inserts. In addition the number of pressings should be considered. Hydraulic tools are naturally better suited for larger quantities than mechanical ones. The mechanical press tools from Klauke are characterised by, among other things, synchronised profile disks, which can be adjusted on both sides in parallel with one-hand operation. In addition, the appropriate cross section can be read on the setting wheel. This greatly lightens the workload.

While you can apply sufficient pressure to small and simple pressings with mechanical pliers, the pressing of large conductors with electro-hydraulic presses is now standard practice.

Current generation electro-hydraulic tools also warn visually and acoustically if the necessary pressing pressure has not been reached. High-quality mechanical pressing tools have integrated mechanisms that guarantee complete pressing.