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de Special 15-16/2009

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ELECTROINSTALLATION:

Which method is correct?Crimp types at a glance

Hüthig & Pflaum Verlag GmbH & Co.Fachliteratur KGLazarettstraße 4, 80636 München

Electroinstallation

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TThe following article will give a review of the most commoncrimp profiles the electrician

should be familiar with (Review: seechart).

For copper and aluminium: Hexagonal crimps

The most common type of crimp forcable lugs and connectors is the hexag-onal crimp as this crimp profile is suitable for copper and aluminium con-ductors (Picture 1). The range of app-lications covering hexagonal crimpsincludes the crimping of conductors asper VDE-0295-categories 2, 5 and 6 andthe processing of non-tension connec-tions of aluminium cables per DIN48201 part 1, and aluminium ropes perDIN EN 50182.

The advantage of a hexagonal crimp is the central force which isapplied consistently from all directionsand over a larger area during thecrimping operation. During this crimp-ing operation the individual strands ofthe conductor are being homo-geneously compressed preventing anydamage.

The result is a strong mechanicalconnection. Due to the even compres-sion the hexagonal crimps are also suit-able for application in medium andhigh voltage areas. However, theseadvantages are faced with some limita-tions.

The complete compression of wirestrands using a hexagonal crimp andstandard crimping dies is not possible.This means: Standard hexagonal crimpsare not gas-tight (see gas-tight ovalcrimps at the end of this article).Therefore it should be observed that a professional hexagonal crimp re-quires the use of crimping dies whichare matched exactly with material anddimensions.

Hexagonal Crimps – DIN TypeHexagonal crimps differ in two ver-sions: One relates to the standardhexagonal crimp in accordance withDIN 48083 part 4 and the other to the manufacturers related hexagonalcrimp. The standardized hexagonalcrimp allows cable lugs and connectorsaccording to DIN 46235 to be crimpedwith certified crimping dies per DIN48083 part 4 (see Picture 2).

Marking on DIN cable lugs provideessential information as to manufac-turer, dimensions and design of thecable lug. These markings indicate forinstance which crimping tools andcrimping dies need to be used toachieve a DIN compliant crimp. Thisdesignation is next to the manufactur-ers’ marking. For instance “KL 18...”

stands for KL: manufacturer (in thiscase Klauke) and 18 for the die code.

The correct die code is a condition ofa professional DIN crimp: Crimping diesused in the crimping tool need to com-ply with the die code shown on thecable lug. The mirror image of the diecode can be seen on the surface of thecrimping dies. After the crimping oper-ation the die reference code can beseen on the barrel of cable lug as partof a visible and recordable quality con-trol procedure.

The die code corresponds approxi-mately to the tube diameter of thecable lug.

The range of copper lugs is approxi-mately from 6 to 58 which correspondwith the cross sections from 6 mm2 to1000 mm2.

Hexagonal crimping dies per DIN48083 part 4 for aluminium lugs andconnectors are described in accordancewith the tube dimensions of lugs perDIN 46239 and connectors per DIN46267 part 2.

The alternative: Manufacturer specific hexagonal crimpsApart from DIN standard hexagonalcrimps the crimping of copper and par-ticularly of cable types per VDE 0295classification 2 also allows for a manu-facturer related hexagonal crimp to beused. Prestigious manufacturers such asKlauke provide hexagonal crimping

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 profes-

sional crimping method. This combination depending on material,

design and application requires the correct crimping profile to be used.

Which method is correct?Crimp types at a glance

AT A GLANCEIn practice both standardised and non-standard crimp profiles are being used.Common amongst all crimping systemsis the requirement that the conductor,cable lug and crimping tools are engi-neered to work with each other ensu-ring a safe connection is achieved.

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Incorrect cable lugs or the use of incorrectcrimping tools can create serious safetydefects in electrical installations and appliances

CRIMPING PROFILESCrimping hexagonal- indent indent quad-point- oval-profiles crimping crimping crimping indent crimping

solderless crimpingterminals

Symbol

Chart: Crimping profiles at a glance

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dies tested and approved to IEC 1238for crimping standard copper cable lugsas per EN 13600. For commercial rea-sons such cable lugs are often used incontrol and switch cabinets. Despiteoffering cost benefits, there is noreduction in quality.

Important: The use of manufacturerrelated crimping dies and cable lugs arenot controlled through the die codes.

Instead it depends more on the crosssection of the cable being used indi-cated in mm2, the cable lug and the diereference. The square mm size is mirrorprinted on the crimping surface of thecrimping dies.

Every manufacturer is responsiblefor the electrical and mechanical dura-bility of connections crimped withthere own tools.

As a safe and professional crimp isdependant on accurately matchingsuitable crimping dies to the cable lugs,Klauke always recommends using themanufacturers approved crimpingtools.

Proven and tested: Indent crimps

The indent crimp represents the oldestelectrical crimp profile. This crimp pro-file is solely suitable for the processingof copper and is often used in controlpanels and switch cabinets operatedwithin a range of 1000 V. The permissi-ble cable range includes stranded con-ductors per VDE 0295 classification 2and also fine stranded and compactedconductors per classification 5 and 6 upto 400 mm2. These conductors can beprocessed with R and F series tubularcable lugs.

Generally two different types ofindent crimps are used: The W-profilefor cross sections from 0.5 mm2 up to16 mm2 and the classic single indentcrimp for cross sections from 6 mm2 upto 240 mm2.

Klauke crimping tools offer the pos-sibility to indent crimp cross sections upto 400 mm2. The characteristics of bothversions are identical: Indent crimps arealways special crimping operations par-ticularly required for fine stranded andcompacted conductors to secure a per-manent connection (Picture 3).

The real benefit of indent crimpingis the simple operation and procedurefor which normally hand operated

crimping tools can be used. The appliedcrimp profile depends on the crosssection of cables, cable lugs andconnectors to be used. Since the indentcrimp does not represent a standard-ized crimp it is imperative to only use high quality materials and toolsapproved per IEC 1238 originating fromone manufacturer. Only in this case the electrician is safeguarded utilizingcable lugs, connectors and tools which are matched to each other andwhich provide and guarantee a safeconnection.

For copper and insulatedmaterials: Indent crimps

Indent crimps have been specificallydeveloped for processing connectionsof cablelugs according to DIN 46234and connectors per DIN 46341 part 1,form A+B, which in turn are suitable forconductors of VDE 0295 classification 2,5 and 6. Cable lugs and connectorscomplying with these standards featurea particular large outside diameterwhich will accept all types of cableswithout any problem. The intenseindent crimp ensures that despite ofthe large outside diameter a long last-ing and “deep acting” crimp isachieved (Picture 4).

The permitted cross sections rangefrom 0.5 mm2 up to 240 mm2. Anindent crimp is also suitable for F-typecable lugs ranging from 10 mm2 up to300 mm2. F-type cable lugs feature alarger diameter; funnel shaped tube toaccept fine stranded and compactedtypes of cables per VDE 0295 classifica-tion 5 and 6 without any splitting. Anindent crimp is also suitable to crimppre-insulated terminals in accordancewith DIN 46234 where the crimp piercesthe insulation.

To avoid that the insulation is dam-aged during the crimping operation itis imperative to only use cable lugs with

Picture 1: A hexagonal crimp is suitable for bothcopper and aluminium conductors. The advanta-ge is the central force which is applied consi-stently from all directions.

Picture 2: The standardized hexagonal crimpallows cable lugs and connectors per DIN 46235 to be crimped with certified crimping dies per DIN 48083 part 4.

Picture 3: Indent (side indent) are always special application crimps which are primarily used for crimping fine stranded and compacted conductors to secure a permanent connection. The applied crimp profiles depend on the cross section of the con-ductor and type of cable lug.

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Picture 4: The intensive indent crimp is only guaranteed when matched materials are use despite the large outside diameters a permanent and „deep acting“ connection will be achieved.

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CONDUCTOR TYPES

• round solid (re), conductors of classifi-cation 1 (described as solid conductors)

• round stranded (rm) conductors ofclassification 2

• fine stranded conductors of classification5 (described as fine stranded conductors)

• compacted conductors of classification 6(described as compacted conductors)

a high quality insulation and appropri-ate crimp profiles (Picture 5).

The indent and the side indent arealso non-standard types of crimp butcan also be used for standard cable lugssuch as terminals per DIN 46234. Forthis reason here it is also important touse tools and materials from a singlequality manufacturer. Materials in-correctly matched are disadvantagedfurther due to the extreme stressesapplied during use. Once a singlestrand has been lost mechanical andelectrical failures in the connection maybecome inevitable.

No dies required: Quad point crimps

The quad point crimp originates in the USA and is being used mainly in panels and switch cabinets up to1000 V. These are also used in otherelectrical connections i.e. in drive sys-tems for locomotives where this type ofcrimp offers the perfect solution. Thiscrimp profile is suitable for cable lugsand connectors ranging from 10 mm2

up to 300 mm2 in combination withcables per VDE 0295 classification 2, 5and 6 (Picture 6).

Attention: Application for use withpre-insulated cable lugs and connectorsis not allowed.

The advantage over a simple indentcrimp is the way the centric force isapplied and that no crimping dies areneeded. This means that with just onecrimping tool all the above mentionedcross sections can be processed. Thequality of the crimp depends solely on

the force and quality of the crimpingtool used.

Gastight: Oval crimps

Gastight oval crimps are being usedpredominantly in the motor industryand in aggressive environments such asagricultural operations or chemicalindustries. A gastight connectionmeans that both conductor and cablelug or connector is compacted togetherso tightly that no notable gap exists(Picture 7). This means that the ingressof fluid or a gaseous medium is not pos-sible under normal atmospheric condi-tions. An oxidation of the individualcrimped strands is prevented and anincrease in resistance is avoided. Forthis reason gastight oval crimps providefor a permanent connection and goodelectrical conductivity.

A gastight connection can be testedby inspecting the polished cross sectionof the lug. There is no restriction to spe-

cific types of cables; therefore all typesof conductors are suitable for gastightoval crimps. To meet the high technicalrequirements of gastight connections itis absolutely imperative to use onlyhigh quality branded crimping toolsand connecting material.

Outlook: Which crimp profile forthe professional solution?

To ensure that durable crimping con-nections are achieved, specific crimpingoperations are required.

In our next edition we will featurethe various crimp profiles in detail andwill explain what needs to be observedto obtain a professional high qualityconnections.

Lutz Remmel,Product Manager / electrical

connecting systems,Gustav Klauke GmbH, Remscheid

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IMPORTANT: SUITABLE TOOLS

For all crimp profiles as a rule it is preconditionto use professional tools, which do not over orunder compress the connector. Incorrect crimpsor the use of the wrong tools can result in an in-crease in joint resistance and may jeopardise

the installation causing fire. To exclude suchconsequences Klauke strongly recommendsfor crimping of their cable lugs the exclusive useof their appropriate crimping tools.

MORE INFORMATION

Articles on this subject• Which cable lug suits which application?

–de Special 1-2/2008• Tubular cable lugs for special applications

– de Special 8/2008• Best practice for installation of Alumi-

nium connectors – de 17/2008 • Professional processing of aluminium

and copper, – de 22/2008

Book on this subjectSchmolke, Herbert: Selection and rating of cables and conductors, 2009, revisededition, 128 pages, paperback, with CD-ROM, 18 ?, ISBN 978-3-8101-0285-0,

www.de-online.info/shop/fachbuecher/schmolkekabel.html (will be released early July 2009)

Picture 5: Cable lugs with a high quality insulation and appropriate crimp profiles ensures that the insulation does not become damaged during the crimping operation.

Picture 6: The quad point crimp is suitable forcable lugs and connectors with cross sectionsranging from 10 mm2 up to 300 mm2 in combination with cable types per VDE 0295 classification 2, 5 and 6.

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Picture 7: Gastight oval crimps provide for apermanent connection and good electricalconductivity. The ingress of fluid or a gaseousmedium is not possible under normal atmosphericconditions. An oxidation of the individual crimpedstrands is prevented and an increase in resistance isavoided.

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