Hexagonal v Indent Methods of Crimping – Cable Lugs, Crimps & Tools
Published 19 Nov 2018
uploaded by Chris Dodds - Thorne & Derrick Sales & Marketing Manager
Thorne & Derrick International, based in the UK, are leading suppliers of cable lugs and associated crimping tools for Low, Medium & High Voltage Cables and Power Systems – this series of articles by Klauke discusses the theory and practise of installing compression type cable lugs and connectors for use with copper and aluminium conductors.
Klauke cable lugs and crimping tools are used by Jointers, Linesmen, Panel Builders and Electrical Engineers to install underground cables and overhead line conductors on power, transmission and distribution networks including LV MV & HV systems, 11kV-33kV.
- The hexagonal crimp: the most common type of crimp for cable lugs and connectors
- Indent crimps representing the traditional electrical cable crimp profile
- Intensive indent crimp is guaranteed a permanent and “deep acting” connection
- Quad point crimps: the advantage is the way the centric force is applied and that no crimping tool dies are needed
- Gastight oval crimps are being used predominantly in aggressive environments
➡ See DIN Standard Cable Crimping for information about connecting and terminating cables in accordance with the German national organisation for standardisation – see DIN 48083 for specific information about lugs, die sets and crimping tools for hexagon compression type cable termination.
Which Cable Crimping Method Is Correct?
Indent of Hexagonal?
Cable crimp types and cable lugs at a glance.
Initially the subject covering crimping profiles seems complicated; the electrical installer is confronted with a number of different cable types, each requiring different cable lugs or connectors and a professional crimping method and associated crimp tools.
This combination depending on material, design and application requires the correct crimping profile to be used.
The following will give a review of the most common cable crimp profiles the electrician or cable jointer should be familiar with when crimping copper or aluminium cables:
Cable Lugs For Copper & Aluminium Cables
The most common type of crimping for copper and aluminium cables, lugs and connectors is the hexagonal crimp as this crimp profile is suitable for both copper and aluminium conductors.
The range of applications covering hexagonal crimps includes the crimping of conductors as per VDE-0295-categories 2, 5 and 6 and the processing of non-tension connections of aluminium cables using aluminium splices per DIN48201 (Copper Stranded Conductors) Part 1 and aluminium ropes per DIN EN 50182 (Conductors for Overhead Lines – Round Wire Concentric Lay Stranded Conductors).
DIN VDE 0295 VDE 0295:1992-06 Standard (Conductors of Cables, Wires & Flexible Cords for Power Installation) is now Withdrawn and replaced by DIN EN 60228 VDE 0295:2005-09 Standard (Conductors of Insulated Cables).
The advantage of a hexagonal crimp is the central force which is applied consistently from all directions and over a larger area during the crimping operation. During this crimping operation the individual strands of the conductor are being homogeneously compressed preventing any damage.
The result is a strong mechanical connection. Due to the even compression the hexagonal crimps are also suitable for application in medium and high voltage cable terminations, connections and joints. However, these advantages are faced with some limitations.
The complete compression of wire strands using a hexagonal crimp and standard crimping dies is not possible. This means standard hexagonal crimps are not gas-tight (see gas-tight oval crimps at the end of this article).
Therefore it should be observed that a professional hexagonal crimp requires the use of crimping dies which are matched exactly with material (aluminium or copper) and dimensions (cross section area and conductor construction).
Hexagonal Crimps – DIN Type
Copper & Aluminium
Hexagonal crimps differ in two versions: one relates to the standard hexagonal crimp in accordance with DIN 48083 Part 4 and the other to the manufacturers related hexagonal crimp. The standardised hexagonal crimp allows cable lugs and connectors according to DIN 46235 to be crimped with certified crimping dies per DIN 48083 Part 4.
DIN 46235 defines the fields of application, dimensions and the marking of compression cable lugs – compression cable lugs to DIN 46235 standard can be used for single, multi-fine and superfine stranded conductors.
Marking on DIN cable lugs provide essential information as to manufacturer, dimensions and design of the cable lug. These markings indicate for instance which crimping tools and crimping dies need to be used to achieve a DIN compliant crimp. This designation is next to the manufacturers’ marking.
For instance “KL 18…” stands for KL: manufacturer (in this case Klauke) and 18 for the die code. The correct die code is a condition of a professional DIN crimp: crimping dies used in the crimping tool need to comply with the die code shown on the cable lug. The mirror image of the die code can be seen on the surface of the crimping dies. After the crimping operation the die reference code can be seen on the barrel of cable lug as part of a visible and recordable quality control procedure.
The die code corresponds approximately to the tube diameter of the cable lug.
The range of copper lugs is approximately from 6 to 58 which correspond with the cross sections from 6sqmm to 1000sqmm. Hexagonal crimping dies per DIN 48083 Part 4 for aluminium lugs and connectors are described in accordance with the tube dimensions of lugs per DIN 46239 and connectors per DIN 46267 Part 2 (Non Tension-Proof Compression Joints For Copper Conductors).
Apart from DIN standard hexagonal crimps the crimping of copper and particularly of cable types per VDE 0295 Classification 2 (Conductors Of Cables, Wires & Flexible Cords For Power Installation) also allows for a manufacturer related hexagonal crimp to be used.
Prestigious manufacturers such as Klauke provide hexagonal crimping dies tested and approved to IEC 1238 (Compression & Mechanical Connectors For Power Cables With Copper or Aluminium Conductors – Part 1: Test Methods & Requirements) for crimping standard copper cable lugs as per BS EN 13600 (Copper & Copper Alloys – Seamless Copper Tubes For Electrical Purposes). For commercial reasons such cable lugs are often used in control and switch cabinets. Despite offering cost benefits, there is no reduction in cable termination quality.
Important: The use of manufacturer related crimping dies and cable lugs are not con-trolled through the die codes. Instead it depends more on the cross section of the cable being used indicated in sqmm, the cable lug and the die reference. The square mm size is mirror printed on the crimping surface of the crimping dies.
Every manufacturer is responsible for the electrical and mechanical durability of connections crimped with there own tools. As a safe and professional crimp is dependent on accurately matching suitable crimping dies to the cable lugs, Klauke always recommends using the manufacturers approved crimping tools.
Proven & Tested – Indent Crimp Lugs
The indent crimp represents the oldest electrical crimp profile. This crimp profile is solely suitable for the processing of copper and is often used in control panels and switch cabinets operated within a range of 1000V.
The permissible cable range includes stranded conductors per VDE 0295 Classification 2 and also fine stranded and compacted conductors per Classification 5 and 6sqmm up to 400sqmm. These conductors can be processed with R and F series tubular cable lugs.
Generally two different types of indent crimps are used: the W-profile for cross sections from 0.5sqmm up to 16sqmm and the classic single indent crimp for cross sections from 6sqmm up to 240sqmm.
Klauke crimping tools offer the possibility to indent crimp cross sections up to 400sqmm.
The characteristics of both versions are identical: indent crimps are always special crimping operations particularly required for fine stranded and compacted conductors to secure a permanent connection.
The real benefit of indent crimping is the simple operation and procedure for which normally hand operated crimping tools can be used. The applied crimp profile depends on the cross section of cables, cable lugs and connectors to be used.
Since the indent crimp does not represent a standardised crimp it is imperative to only use high quality materials and tools approved per IEC 1238 originating from one manufacturer.
Only in this case the electrician is safeguarded utilising cable lugs, connectors and tools which are matched to each other and which provide and guarantee a safe connection.
copper & insulated materials
Indent crimps have been specifically developed for processing connections of cable lugs according to DIN 46234 and connectors per DIN 46341 part 1, form A+B, which in turn are suitable for conductors of VDE 0295 Classification 2, 5 and 6.
Cable lugs and connectors complying with these standards feature a particular large outside diameter which will accept all types of cables without any problem.
The intense indent crimp ensures that despite of the large outside diameter a long lasting and “deep acting” crimp is achieved.
The permitted cross sections range from 0.5sqmm up to 240sqmm. An indent crimp is also suitable for Klauke F-type cable lugs ranging from 10sqmm up to 300sqmm.
F-type cable lugs feature a larger diameter, funnel shaped tube to accept fine stranded and compacted types of cables per VDE 0295 Classification 5 and 6 without any splitting.
An indent crimp is also suitable to crimp pre-insulated terminals in accordance with DIN 46234 where the crimp pierces the cable insulation. To avoid that the insulation is damaged during the cable crimping operation it is imperative to only use cable lugs with a high quality insulation and appropriate crimp profiles.
The indent and the side indent are also non-standard types of crimp but can also be used for standard cable lugs such as terminals per DIN Standard 46234. For this reason here it is also important to use crimping tools and materials from a single quality manufacturer. Materials incorrectly matched are disadvantaged further due to the extreme stresses applied during use. Once a single strand has been lost mechanical and electrical failures in the connection may become inevitable leading to cable failures.
No dies required – Quad point Cable crimps
The quad point crimp originates in the USA and is being used mainly in panels and switch cabinets up to 1000V. These are also used in other electrical connections i.e. in drive systems for locomotives where this type of crimp offers the perfect cable termination solution.
This crimp profile is suitable for cable lugs and connectors ranging from 10sqmm up to 300sqmm in combination with cables per VDE 0295 Classification 2, 5 and 6.
Attention: Application for use with pre- insulated cable lugs and connectors is not allowed. The advantage over a simple indent crimp is the way the centric force is applied and that no crimping dies are needed. This means that with just one crimping tool all the above mentioned cross sections can be processed. The quality of the crimp depends solely on the force and quality of the crimping tool used.
Gastight Oval crimp Lugs
Gastight oval crimps are being used pre-dominantly in the motor industry and in aggressive environments such as agricultural operations or chemical industries with potentially explosive atmospheres characterised by flammable gases in hazardous areas. A gastight cable termination connection means that both conductor and cable lug or connector is compacted together so tightly that no notable gap exists to prevent gas migration.
This means that the ingress of fluid or a gaseous medium is not possible under normal atmospheric conditions. An oxidation of the individual crimped strands is prevented and an increase in resistance is avoided.
For this reason gastight oval crimps provide for a permanent cable connection and good electrical conductivity.
A gastight connection can be tested by inspecting the polished cross section of the cable lug. There is no restriction to specific types of cables; therefore all types of conductors are suitable for gastight oval cable crimps.
To meet the high technical requirements of gastight connections it is absolutely imperative to use only high quality branded crimping tools and connecting material.
Outlook: Which crimp profile for the professional solution?
To ensure that durable crimping connections are achieved, specific crimping operations are required. In our next edition we will feature the various crimp profiles in detail and will explain what needs to be observed to obtain professional high quality connections, joints and cable terminations.
Review other Blogs in this series of articles about Cable Lugs, Crimping Cables & Tools:
LV MV HV Cable Accessories & Substation Electrical Equipment
Thorne & Derrick are Specialist Distributors of leading manufacturers of Cable Accessories, Jointing & Installation Equipment.
LV MV HV cable accessories used to joint, terminate, connect, cleat and gland power cables to air and gas insulated substations, transformers, switchgear and overhead line networks.
Hover over our Interactive Logo Grid to learn more about our product ranges.
LV 600/1000V ◊ MV 11kV 33kV ◊ HV 66kV 132kV
Substation & Overhead Line Electrical Safety Equipment
Manufactured by CATU Electrical to enable the safe construction, maintenance and repair of underground cables and overhead lines network up to EHV (400kV).
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