The special cable lugs: tubular cable lugs for special applications

  • F cable lugs for fine and superfine stranded conductors simplify the insertion of Class 5 and 6 spliced conductors to DIN EN 60288.
  • Tubular cable lugs for single-stranded conductors are set apart by an adapted tube diameter.
  • Tubular cable lugs for control cabinet connections have a much narrower palm
  • Stainless steel tubular cable lugs are especially suited to use in aggressive environmental conditions
  • Nickel tubular cable lugs are suited to use in very high temperatures

Many electrical engineers will be familiar with the problem of not being able to use standard cable lugs because they do not exactly match the conductors, for example. The attempt to push a fine or superfine stranded conductor into a cable lug presents this problem: The cable strands splay and the strands do not enter the cable lug correctly. To prevent such annoying situations from the outset, Klauke offers a broad range of special cable lugs. If you can’t find a solution in our catalogue, speak to us.

These special cable lugs can be used to connect all conductor classes without a problem. Their design is geared towards the special properties of the various classes of conductors defined in DIN EN 60228. These are as follows: 


  • Round single-stranded conductors (re), Class 1 (also known as solid conductors)
  • Round multi-stranded conductors (rm), Class 2
  • Fine-stranded conductors, Class 5 (also designated as a flexible conductor)
  • Fine-stranded conductors, class 6 (also referred to as highly-flexible conductors)

F cable lugs: ideal solution for fine and superfine stranded conductors

The use of “F” series tubular cable lugs can prevent the common problems of inserting Class 5 and 6 fine and superfine stranded conductors to DIN EN 60228. These lugs are suitable, for instance, for processing larger conductor cross-sections in control cabinet construction, in galvanising plants or for use in rail vehicles.

F cable lugs have a larger tube diameter than standard cable lugs. Also, they are widened into a bell shape in a complex manufacturing process to guarantee better cable insertion.  So F tubular cable lugs allow the conductor to be inserted easily and reliable.

Of course, this also has safety-related effects: cross-section tapering due to kinked or un-inserted strands is prevented, and so the full cross section of the conductor is retained. F cable lugs also have markings. These are as follows: stamping »710F12 K12-150f« stands for


  • K: Manufacturer code (in this case Klauke)
  • 12: Metric bolt dimension of the bore for the connecting bolt (in this case M12 bolt)
  • 150: Conductor cross-section in mm²
  • f: “F” series tubular cable lug (fine stranded)
  • 710F12: Cable lug item number


Indent and quad-point indent crimping or notch crimping with suitable tools is the ideal solution for achieving a professional crimping process for F cable lugs.

Suitable for the “F” series of tubular cable lugs, Klauke also offer joints for conductor extensions or for repair purposes. The recommended crimping methods are the same as those for F tubular cable lugs. “F” series cable lugs and joints consist of electrolytic copper tube. 

To guarantee protection from corrosion, these cable lug types are also tin-plated. The commercially-available conductor cross-sections are between 10 mm² and 300 mm². In addition to the straight versions, 45° or 90° angled versions, as well as models with an inspection hole, which conveniently shows whether the conductor has been fully inserted in the cable lug, are likewise available.

Klauke cable lugs are annealed in a special manufacturing process. Stresses are removed from the connector and the risk of breakage is significantly reduced, thereby increasing reliability.

Klauke's product range:

> Tubular cable lugs, Cu, F-Series

> Angled tubular cable lugs, Cu, 90° offset, F-Series

Tubular cable lugs for single-stranded conductors (re)

Class 1 single-stranded conductors to DIN EN 60228 can be best crimped with “E” series tubular cable lugs (cable lugs for solid conductors). These are also made from tin-plated electrolytic copper. These cable lugs have an adapted tube diameter, which guarantees optimum crimping of solid conductors. The fields of application include those involving solid single stands, in transformer or engine construction for example. For these cable lugs, we recommend two-point indent and hexagonal crimping.

Tubular cable lugs for single-stranded conductors are recognised by their smaller diameter and also by their marking: The stamping ends with an “E” for “eindrähtig”, the German for “single-stranded”. For example: KL 10 50 E. 

For “E” series tubular cable lugs, there are suitable joint and T- and cross-connectors with matching inside diameters for single-stranded conductors.

Klauke's product range:

> Tubular cable lugs, Cu, solid conductor type

> Butt connectors, Cu, solid conductor type

> T-connectors, Cu, solid conductor type

> Cross-connectors, Cu, solid conductor type

Tubular cable lugs for narrow switchgear connections

In control cabinet construction, installation engineers face several challenges. Aside from the fact that confined spaces usually hamper progress anyway, connecting conductors to powerful switchgear proves especially tricky – from a certain conductor cross-section onwards, conventional tubular cable lugs do not fit into connecting terminal provided. For these difficult applications, special tubular cable lugs for switchgear connections have been developed (“SG cable lugs”). They have a much narrower palm which is readily compatible with the switch gear connection.

The palm of these cable lugs is not only much narrower than that of a conventional cable lug, it is also slightly thicker. This is down to the production process, which uses the same amount of  electrolytic copper as for a conventional tubular cable lug.

This tubular cable lug profile is therefore best suited for use in control cabinet construction. They can be processed in exactly the same way as the “standard” cable lug. Suitable crimp profiles would be the hexagonal crimp, the indent crimp or the notch crimp.

The bores are adapted to the dimensions of connecting terminals of standard switchgear. Here too, there are versions with a practical inspection hole.

We strongly advise against cutting off the palm sides of standard tubular cable lugs to make it fit into the connecting terminal of the switchgear. Such manipulations can be highly dangerous. In the worst case, there is the risk of fire due to the reduced cable lug cross-section.

Klauke's product range

> Tubular cable lugs for switchgear connections


Stainless steel and nickeltubular cable lugs for aggressive or high-temperature environments

Hostile environments likewise call for special cable lugs. Tubular cable lugs from stainless steel and nickel withstand most conditions and are the ideal solution for crimping copper conductors.

Stainless steel tubular cable lugs are extremely acid and corrosion resistant, and hence especially suited to use in the chemical and foodstuffs industries or for sectors where connectors are exposed to seawater.

Stainless steel is not only highly resistant to acids, it can also withstand high temperatures. Stainless steel cable lugs can therefore be used at ambient temperatures of up to 400°C without a problem. 

When the going gets even hotter and cable lugs for particularly high temperatures are required, for example in the high-temperature sector of annealing or heating furnaces, nickel tubular cable lugs are the answer. These lugs are able to withstand temperatures of up to 650°C.

Stainless steel and nickel tubular cable lugs are suitable for Class 2 and 5 fine-stranded conductors, and also for pre-rounded sector-shaped conductors.

For cable lugs of these resistant materials, we recommend the indent crimp, likewise for the corresponding joint with butt mark.

Klauke's product range:

> Tubular cable lugs, stainless steel

> Tubular cable lug, nickel

> Tubular cable lug, nickel, fork type