Abisolieren von Solarleitungen

Stripping solar cables: Bad stripping results create a bad connection

I often hear at trade fairs and user visits that it is actually not that important how you strip solar cables. Many people believe that this can also be done with a simple cutter or knife. A few scratches or even a missing strand wouldn’t be a big deal. But, is this really the truth?

I recently spoke to a crimping and wire stripping specialist about this topic. Inspired by this conversation, I explained some important background information. I have summarized these for you in this article.

The process of cable stripping

Stripping involves removing the external insulation. The outer jacket is there to protect the inner conductor against corrosion and also against short circuits to other cables.
The wire stripping process is necessary in order to be able to connect the cable. The insulation is scratched or cut through and then removed either by hand or with a wire stripping tool. The prerequisite for a good wire stripping result is the choice of the appropriate wire stripping tool.

The importance of the right wire stripping tool

Not every tool is suitable for every cable. If unsuitable work equipment is used, the inner conductors may be damaged or the insulation of the conductors may be cut. The insulation can also pull out at the cut edge or insulation residue can stick to the conductor surface due to tearing. The insulation can also be squeezed too much. However, it may also be the case that the tool does not cut into the sheath at all because it is too tough, too hard or simply too thick for the cutting depth of the blade.
Some wire stripping tools cut the insulation down to the strand and sometimes even touch it. With JOKARI tools, the insulation is only scratched. When the insulation is pulled off, it breakes so that it comes off in one piece, but the blades have in no way touched the conductor before.

PV cables / solar cables – something very special

The connection between the solar modules and the inverter is particularly important. The cables used here generate voltages of up to 1,000 volts. For large solar systems it can even be up to 1,500 volts.
The PV cable not only has to withstand this load but also ensures that the current stays in the conductor and that no one gets an electric shock if parts of the system are touched.
The inner copper conductor leads the electricity generated by the solar panels. The insulation of the cables ensures that the current remains in the cable and that it is protected.

The insulation of solar cables

The insulation has to meet special requirements: It protects the conductor from mechanical stress. But also from much more aggressive external influences such as UV radiation, acid rain and strong temperature changes.
Therefore, the insulation of solar cables consists of two layers. The outer layer (black in the picture) protects the cable against environmental influences, while the inner layer (white in the picture) is the actual electrical insulation layer, which also protects the cable against the enormous temperature influences.

The outer black layer protects the cable against environmental influences, the white inner layer is the actual electrical insulation layer. It protects the cable against the enormous temperature influences.

A good connection is of great importance

The quality of the cabling and connections is not only an important factor for the yield of the system. They are also crucial for the security of the entire system. Unfortunately, in practice this issue often receives too little attention – both during installation and when selecting the right products.
What many users do not take into account is the fact that a clean stripping result is an elementary basis for a good connection. Imprecise and incorrectly stripped, damaged cables can result in the connection crimp or spring terminal of the connector not being able to make proper contact.

Using the right tools

For this reason, we at JOKARI recommend our PV-Strip Pro. With its ergonomic and well thought-out shape, this lightweight cable stripper ensures that professional users can strip almost all solar cables from 1.5 to 16mm2 professionally and quickly. The proven space-saving shape enables uncomplicated use in almost all areas of application, whether on the roof, in narrow movement areas or on the inverters and distribution boards.

What means stripped in a bad way?

Due to the material structure, copper or aluminum conductors of the PV cables can break off due to injuries such as notches or can become very hot due to damage/injury.
Especially if several strands break off after a notch, the available cross-section is no longer sufficient for unhindered current flow. This in turn can lead to severe heating and even a cable fire. It is often these errors and causes that can damage not only electrical systems, but entire buildings and people. These effects can appear within a few hours or even after years. Therefore, great care should be taken right from the start of an electrical installation, i.e. when simply stripping the insulation.

Possible consequences of badly stripped cables

Damaged insulation can generate leakage currents. The resulting current can be transferred to the system and cause electric shocks or short circuits. Furthermore, leaks can occur in the connector. In the long term, the contact points in the connector corrode, resulting in higher transition resistances. The consequences can be loss of performance, heating or even a cable fire.
If the strand is damaged directly when stripping the insulation incorrectly, for example with a cutter knife or side cutters, corrosion will also occur directly on the conductor in the connection. Reducing the cross-section can also be problematic and in turn lead to loss of performance, heating and even cable fire.

Conclusion: The right wire stripping tool saves time and prevents errors

In our conversations with users, we hear again and again that an experienced skilled worker can achieve good stripping results with side cutters or a cutter knife. This may certainly be true in some cases. But this is often not process-safe and, especially for inexperienced users, it can lead to very large errors and even the loss of a system. In contrast, the simple use of a professional stripping tool for solar cables, such as the PV-Strip Pro, often saves enormous amounts of time and protects the cables from injury, but above all also protects the user. It always pays off and ultimately ensures satisfied customers!

You might also be interested in: „Stripping solar cables: the right wire stripping tool“

To the author Frank J. Goebbels