The procedure for the copper sec-tion is absolutely identical as on coppercompression cable lugs. The crimpingmarks on the product give detailedinformation as to origin and applica-tion of the Al/Cu compression joints.The marking “KL14 50 rm/70 re/se” sig-nifies

• KL: Manufacturer (in this caseKlauke)

• 14: Die code• 50: Cross section of designed

conductor in mm2

• rm/sm: for round stranded andsector stranded conductors

• 70: cross section of solid conductor in mm2

• re/se: for round solid and sector solidconductors

The marks on the copper sectionalso indicate the correct procedure. Thestandard suggests crimping dies acc. toDIN 48083 part 1, 3 and 4 for solid-, fineand fine stranded conductors; forbraided round wires the standardrefers to specifications of the manufac-turer. Generally Klauke recommendsusing hexagon crimping dies acc. to DIN48083 part 4 for processing the coppersection of their compression joints.

Advice: When using crimp connec-tions in the ground it should be strictlyobserved that the connecting jointsshould be protected against moisture.((PPiiccttuurree 99)). For this application Klaukerecommends use of cast-resin joints.

For the application of Al/Cu com-pression joints and cable lugs the fol-lowing should also be considered:These products should not be exposedto bending stresses which could frac-ture the contact point. Application onoverhead lines is therefore excluded.

Preview: Crimp profiles at a glance

With a further feature story in one ofthe next issues of “de” we close theseries on cable lugs and connectors.This article will deal with the variouscrimp profiles which correct selectiondepends very much on materials andcable types used.

Lutz Remmel, Product Manager Electrical connecting systems,

Gustav Klauke GmbHwww.klauke.com

MEHR INFOS

Contribution on this issue http://www.de-online.info/archiv/2008/01-02/index.php?Page=elektroinstallation04.html• Which cable lug for which appli-

cation?, “de” 1-2/2008, S.33 http://www.de-online.info/archiv/2008/08/index.php?Page=elektroinstallation02.html• Cable lugs for special applications,

“de” 8/2008, S.27http://www.de-online.info/archiv/2008/17/index.php?Page=elektroinstallation02.html• Best Practise for Installation of

Aluminium Connectors, „de“17/2008, S.26

Book on this issueSchmolke, Herbert: Selection anddesign of cables and conductors2007.2, revised and extended edition.120 pages, paperback, with CD Rom,18€, ISBN 978-3-8101-0263-8, www.de-online.info/ shop/fachbuecher/schmolke_kabel.html

www.de-online.info

Der Elektro- und Gebäudetechniker

de Special 22/2008

ORGAN DES

ZVEH

ELECTROINSTALLATION:

Accurately connecting copperand aluminium

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

Engineers professional tool-bag

All in one. One for all.

For more information please visit www.klauke.com

KL390IS (6-pieces) KL130PM1IS KL130PM2IS

KL044200IS KL050205IS KL020165IS

KL745HK KL710 KL403

The quality bag comes with genuine

Klauke tools.

The ideal companion for electricians, fitters or installation engineers:

The Klauke Engineers professional tool-bag has space for the complete

tool range and provides safe storage of laptop, documents, mobile phone or

business cards. The clever compartmentation as well as removable single

components turn the tool-bag into a very flexible system meeting all

day-to-day requirements.

Electroinstallation

5 de Special

Picture 9: When used in theground cast-resin joints protect

the connections against moisture.It is important to consider that the

connection is not subject tobending to avoid the risk of frac-

ture. Sour

ce: K

lauk

e

BRD

ESO

ND

ER22

2008

GB

10.

000

02/0

9 I

minium / copper compression cable lugsare the same as those for pure alu-minium versions.

Quality products manufactured bymarket leaders such as Klauke feature aconsistent material thickness, exactdiameters and correct fit are a prereq-uisite for ensuring high safety stan-dards are always met. Like aluminiumcompression cable lugs conforming toDIN 46239, aluminium/copper compres-sion cable lugs feature a barrier designallowing the use of oil soaked andpaper insulated cables which preventsoil leakage.

Aluminium conductors at a glance

Aluminium conductors are available infour different versions which require insome cases special processing. Theseare ((sseeee ppiiccttuurree 44)).

• round solid conductor(re)• sector solid conductor(se)• round stranded conductor (rm)• sector stranded conductor (sm)

These abbreviations will be foundnext to other markings on all Al/Cucompression cable lugs and identifywhich conductors will suit the appropri-ate cable lug. ((sseeee ppiiccttuurree 55)).

Markings on the product providethe installer with essential informa-

tions. Marking “16 KL25 150 rm/sm 185re/se” stands for

• 16: Metric bolt size for connectingbolt – size M16.

• KL: Manufacturer (in this case Klauke)

• 25: Die code • 150: Cross section of conductor

in mm2

• rm/sm: for round multi-stranded andsector stranded conductors

• 185: Cross section of conductor in mm2

• re/se: for round single stranded solidand single sector solid conductors

The die code also needs special con-sideration. For an accurate and safecrimp the die reference should be thesame as that shown on the cable lug.The die code can be seen on the dieface as a mirror image so that aftercompression the die code is visible onthe cable lug for final control andinspection.

For an accurate processing of Al/Cucompression cable lugs it is generally

4 de Special

Acopper-aluminium connectionis used for instance in an indus-trial estate where local business

use copper supply cables which arethen fed off an aluminium ring main.But also in electrical substations it isnecessary to connect aluminium con-ductors to copper bus bars. The mainproblem here is that connecting alu-minium and copper is not straight-forward. To ensure a safe and correctconnection the use of special alu-minium/copper cable lugs and connec-tors are essential. ((PPiiccttuurree 11)).

Aluminium-Copper:A problematic connection

Generally aluminium is a reactive mate-rial that oxidizes easily, but in practice ithas proved to offer good corrosionresistance. This characteristic is due to achemical reaction that takes placewhen in contact with atmospheric oxy-gen resulting in a very thin but also

very resistant oxide layer being formed.(oxide barrier)

When metals are connected to thosewith a higher electrical potential suchas copper in the presences of an elec-trolyte (condensed water) will result inan electrochemical reaction takingplace. During this process the differ-ences caused in electrochemical poten-tial can have a significant impact.

An electrical circuit is generated bythe copper electrode (anode), the elec-trolyte (water) and the aluminium elec-trode (cathode). The voltage generatedin this copper and aluminium circuit“semi metallic” state results in a shortcircuit.

As a result of the current generatedthe Aluminium surface breaks downcausing the metal to electrolyticallydecompose. This destructive process isvisible as a kind of blooming oxidationand begins already with the existenceof tiny copper particles on the alu-minium; this ongoing reaction itselfdoes not cause the copper to corrode.In an electrical connection however theresistance is increased leading toincreased temperatures which then inthe worst case lead to a fire.

Therefore when connecting copperand aluminium it is important to ensure

that no moisture can enter the connec-tions. In an environment where mois-ture is present the contact pointsbetween the copper and aluminiumneed to be protected by using accurateoperating procedures. ((sseeee ppiiccttuurree 22)).Primarily this requires the use of alu-minium/copper cable lugs and connec-tors. Due to the design of these lugsareas where moisture could accumu-late and where the oxidation processcould start have been avoided. For thisreason aluminium/copper cable lugsand connectors are specified for the usein off-shore wind power stations.

Aluminium/copper compressioncable lugs

Leading manufacturers of high qualitycompression cable lugs for connectingaluminium connectors with copper busbars ((sseeee ppiiccttuurree 33)) consist of an elec-trolytic aluminium (E-Al) compressionand are joined to a copper palm (to EN13600).

The available cross sections rangefrom 16 mm2 up to 400 mm2. The fieldof application covers in principle allnon-tension connections of aluminiumcables acc. to DIN 48201, part 1, andaluminium ropes acc. to DIN 50182.Specifications and processing of alu-

2 de Special

Copper due to its outstanding electrical properties are always

the first choice when selecting a conductor for an electrical

connection. A practicable alternative in many cases is aluminium

particularly because of its low weight and easy application. In

practice however the electrician can find it challenging to connect

both these materials in a professional manner.

Accurately connectingcopper and aluminium

Electroinstallation IN BRIEFCopper and Aluminium conductorsare difficult to connect to each other.It is therefore necessary to avoid theingress of moisture at all costs. Forthese applications special cable lugsare needed and accurate operatingprocedures should be adhered to.

Electroinstallation

Picture 1: Use of an incorrect crim-ping die and/or an incorrect crimpwill result in an over compression(right) or an under compression(left) and in the worst case in fire.

Sour

ce: K

lauk

e

Picture 2: The construction of Al/Cucable lugs prevents any gaps which

would allow the accumulation ofliquid to take place which would start

the oxidation process.

Sour

ce: K

lauk

e

Picture 3: A professional connection of an aluminium conductor with acopper busbar is done by means of an aluminium cable lug and a copperpalm.

Sour

ce: K

lauk

e

recommended to use hexagon crimp-ing dies acc. to DIN 48083 part 4. Inorder to ensure an accurate and profes-sional crimp avoiding over or undercompression is the use of appropriatecrimping tools. Poor crimps can result inan increase in joint resistance and tem-peratures that can lead to fires. To pre-vent such issues Klauke solely recom-

mend using the manufacturers crimp-ing tools to crimp their cable lugs.

For instance the special crimpingdies for aluminium have a crimp widthof 7 mm, i.e. 2 mm wider than thecrimping dies for copper cable lugs andconnectors. This, however, only appliesto 60 kN crimping dies. The reason forthis is that dies with a larger crimpwidth are able to connect a wider con-ductor surface area with the cable lugsand balance the poor conductivity ofaluminium. To easily identify which die

should be used, Klauke manufacturesaluminium dies in a silver colour while dies for copper are yellow-goldcoloured.

Connecting compound for alumi-nium connecting material

All cable lugs and connectors for alu-minium conductors come with a specialcompound ((sseeee ppiiccttuurree 66)). This aggra-vates the non-conductive oxide layerwhich is quickly formed on the surface.This compound improves the contactproperties and enables a perfect elec-trical connection, and also prevents fur-ther oxygen penetrating the contactjoints where further oxidation couldtake place. To maintain the functionalcapability of the compound all leadingbrand cable lugs are sealed with a plas-tic plug to prevent the compound fromdrying-out and leakage.

Al/Cu Connectors

For a correct connection of aluminiumand copper conductors leading manu-facturers such as Klauke offer reductioncompression joints with a cross sectionrange from 10 mm2 up to 300 mm2.((sseeee ppiiccttuurree 77)). These products servemainly the reconstruction of powerlines, i.e. non-tension connections ofaluminium conductors acc. to DIN EN60228 resp. aluminium wires acc. to DINEN 50182 with copper cables acc. to DIN48201, part 1 and copper conductorsacc. to DIN EN 60228. These compres-sion joints consist of interconnectedaluminium (E-Al) and copper parts (acc.to EN 13600).

Normally the aluminium part of the cross section has a much largerdiameter ((sseeee ppiiccttuurree 88)) to compen-sate for the poor conductivity of alu-minium. As with the cable lugs here tooplastic plugs are used to preventdrying-out and leakage. Important: The use of Al/Cu compression jointsrequires that the correct processingguidelines for copper and aluminiumare observed.

Consequently the aluminium sectionneeds to be crimped like an aluminiumcompression cable lug (see above).Characteristically for Al/Cu compressionjoints are the different crimping markswhich are 7 mm on the aluminium sec-tion and 5 mm on the copper part forcrimping dies up to 60 kN.

Picture 4: Various shapes of aluminiumconductors

Sour

ce: K

lauk

e

Sour

ce: K

lauk

e

re – round solid conductor

se – sector solid conductor

rm – round stranded conductor

sm – sector stranded conductor

Picture 5: The markings on the cable lug provideinformation relating to the crimps, the manu-facturer, cross section and allocation of cable.

Source: Klauke

Sour

ce: K

lauk

e

Picture 6: High quality aluminium cable lugs come with a special compound whichimproves the contact properties and ensuresa perfect electrical connection.

Picture 8: Normally the aluminiumsection (right) has a larger diameterthan the copper section (left) to equalizethe poor conductivity of aluminium.

Sour

ce: K

lauk

e

Picture 7: Aluminium and copperconductors with different crosssections are being connectedusing reduction sleeves.

Greenlee CSJ-100 open jaw meter

Non-contact voltage detection in the narrowest spaces – the Greenlee CSJ-100 digital open jaw meter makes it possible.

It is designed for AC current measurements of up to 200 A AC and for AC and DC voltages up to 1000 V. It meets the requirements of safety category IV up to 600 V or category III up to 1000 V.

Additional product features are the data-hold-function for recording measurements, the automatic power-off for longer battery life, an audible continuity check and a diode test.

www.klauke.com

KLA09-002_Anz_CSJ100_A5q_eng_RZ.1 1 26.01.2009 16:10:45 Uhr

minium / copper compression cable lugsare the same as those for pure alu-minium versions.

Quality products manufactured bymarket leaders such as Klauke feature aconsistent material thickness, exactdiameters and correct fit are a prereq-uisite for ensuring high safety stan-dards are always met. Like aluminiumcompression cable lugs conforming toDIN 46239, aluminium/copper compres-sion cable lugs feature a barrier designallowing the use of oil soaked andpaper insulated cables which preventsoil leakage.

Aluminium conductors at a glance

Aluminium conductors are available infour different versions which require insome cases special processing. Theseare ((sseeee ppiiccttuurree 44)).

• round solid conductor(re)• sector solid conductor(se)• round stranded conductor (rm)• sector stranded conductor (sm)

These abbreviations will be foundnext to other markings on all Al/Cucompression cable lugs and identifywhich conductors will suit the appropri-ate cable lug. ((sseeee ppiiccttuurree 55)).

Markings on the product providethe installer with essential informa-

tions. Marking “16 KL25 150 rm/sm 185re/se” stands for

• 16: Metric bolt size for connectingbolt – size M16.

• KL: Manufacturer (in this case Klauke)

• 25: Die code • 150: Cross section of conductor

in mm2

• rm/sm: for round multi-stranded andsector stranded conductors

• 185: Cross section of conductor in mm2

• re/se: for round single stranded solidand single sector solid conductors

The die code also needs special con-sideration. For an accurate and safecrimp the die reference should be thesame as that shown on the cable lug.The die code can be seen on the dieface as a mirror image so that aftercompression the die code is visible onthe cable lug for final control andinspection.

For an accurate processing of Al/Cucompression cable lugs it is generally

4 de Special

Acopper-aluminium connectionis used for instance in an indus-trial estate where local business

use copper supply cables which arethen fed off an aluminium ring main.But also in electrical substations it isnecessary to connect aluminium con-ductors to copper bus bars. The mainproblem here is that connecting alu-minium and copper is not straight-forward. To ensure a safe and correctconnection the use of special alu-minium/copper cable lugs and connec-tors are essential. ((PPiiccttuurree 11)).

Aluminium-Copper:A problematic connection

Generally aluminium is a reactive mate-rial that oxidizes easily, but in practice ithas proved to offer good corrosionresistance. This characteristic is due to achemical reaction that takes placewhen in contact with atmospheric oxy-gen resulting in a very thin but also

very resistant oxide layer being formed.(oxide barrier)

When metals are connected to thosewith a higher electrical potential suchas copper in the presences of an elec-trolyte (condensed water) will result inan electrochemical reaction takingplace. During this process the differ-ences caused in electrochemical poten-tial can have a significant impact.

An electrical circuit is generated bythe copper electrode (anode), the elec-trolyte (water) and the aluminium elec-trode (cathode). The voltage generatedin this copper and aluminium circuit“semi metallic” state results in a shortcircuit.

As a result of the current generatedthe Aluminium surface breaks downcausing the metal to electrolyticallydecompose. This destructive process isvisible as a kind of blooming oxidationand begins already with the existenceof tiny copper particles on the alu-minium; this ongoing reaction itselfdoes not cause the copper to corrode.In an electrical connection however theresistance is increased leading toincreased temperatures which then inthe worst case lead to a fire.

Therefore when connecting copperand aluminium it is important to ensure

that no moisture can enter the connec-tions. In an environment where mois-ture is present the contact pointsbetween the copper and aluminiumneed to be protected by using accurateoperating procedures. ((sseeee ppiiccttuurree 22)).Primarily this requires the use of alu-minium/copper cable lugs and connec-tors. Due to the design of these lugsareas where moisture could accumu-late and where the oxidation processcould start have been avoided. For thisreason aluminium/copper cable lugsand connectors are specified for the usein off-shore wind power stations.

Aluminium/copper compressioncable lugs

Leading manufacturers of high qualitycompression cable lugs for connectingaluminium connectors with copper busbars ((sseeee ppiiccttuurree 33)) consist of an elec-trolytic aluminium (E-Al) compressionand are joined to a copper palm (to EN13600).

The available cross sections rangefrom 16 mm2 up to 400 mm2. The fieldof application covers in principle allnon-tension connections of aluminiumcables acc. to DIN 48201, part 1, andaluminium ropes acc. to DIN 50182.Specifications and processing of alu-

2 de Special

Copper due to its outstanding electrical properties are always

the first choice when selecting a conductor for an electrical

connection. A practicable alternative in many cases is aluminium

particularly because of its low weight and easy application. In

practice however the electrician can find it challenging to connect

both these materials in a professional manner.

Accurately connectingcopper and aluminium

Electroinstallation IN BRIEFCopper and Aluminium conductorsare difficult to connect to each other.It is therefore necessary to avoid theingress of moisture at all costs. Forthese applications special cable lugsare needed and accurate operatingprocedures should be adhered to.

Electroinstallation

Picture 1: Use of an incorrect crim-ping die and/or an incorrect crimpwill result in an over compression(right) or an under compression(left) and in the worst case in fire.

Sour

ce: K

lauk

e

Picture 2: The construction of Al/Cucable lugs prevents any gaps which

would allow the accumulation ofliquid to take place which would start

the oxidation process.

Sour

ce: K

lauk

e

Picture 3: A professional connection of an aluminium conductor with acopper busbar is done by means of an aluminium cable lug and a copperpalm.

Sour

ce: K

lauk

e

recommended to use hexagon crimp-ing dies acc. to DIN 48083 part 4. Inorder to ensure an accurate and profes-sional crimp avoiding over or undercompression is the use of appropriatecrimping tools. Poor crimps can result inan increase in joint resistance and tem-peratures that can lead to fires. To pre-vent such issues Klauke solely recom-

mend using the manufacturers crimp-ing tools to crimp their cable lugs.

For instance the special crimpingdies for aluminium have a crimp widthof 7 mm, i.e. 2 mm wider than thecrimping dies for copper cable lugs andconnectors. This, however, only appliesto 60 kN crimping dies. The reason forthis is that dies with a larger crimpwidth are able to connect a wider con-ductor surface area with the cable lugsand balance the poor conductivity ofaluminium. To easily identify which die

should be used, Klauke manufacturesaluminium dies in a silver colour while dies for copper are yellow-goldcoloured.

Connecting compound for alumi-nium connecting material

All cable lugs and connectors for alu-minium conductors come with a specialcompound ((sseeee ppiiccttuurree 66)). This aggra-vates the non-conductive oxide layerwhich is quickly formed on the surface.This compound improves the contactproperties and enables a perfect elec-trical connection, and also prevents fur-ther oxygen penetrating the contactjoints where further oxidation couldtake place. To maintain the functionalcapability of the compound all leadingbrand cable lugs are sealed with a plas-tic plug to prevent the compound fromdrying-out and leakage.

Al/Cu Connectors

For a correct connection of aluminiumand copper conductors leading manu-facturers such as Klauke offer reductioncompression joints with a cross sectionrange from 10 mm2 up to 300 mm2.((sseeee ppiiccttuurree 77)). These products servemainly the reconstruction of powerlines, i.e. non-tension connections ofaluminium conductors acc. to DIN EN60228 resp. aluminium wires acc. to DINEN 50182 with copper cables acc. to DIN48201, part 1 and copper conductorsacc. to DIN EN 60228. These compres-sion joints consist of interconnectedaluminium (E-Al) and copper parts (acc.to EN 13600).

Normally the aluminium part of the cross section has a much largerdiameter ((sseeee ppiiccttuurree 88)) to compen-sate for the poor conductivity of alu-minium. As with the cable lugs here tooplastic plugs are used to preventdrying-out and leakage. Important: The use of Al/Cu compression jointsrequires that the correct processingguidelines for copper and aluminiumare observed.

Consequently the aluminium sectionneeds to be crimped like an aluminiumcompression cable lug (see above).Characteristically for Al/Cu compressionjoints are the different crimping markswhich are 7 mm on the aluminium sec-tion and 5 mm on the copper part forcrimping dies up to 60 kN.

Picture 4: Various shapes of aluminiumconductors

Sour

ce: K

lauk

e

Sour

ce: K

lauk

e

re – round solid conductor

se – sector solid conductor

rm – round stranded conductor

sm – sector stranded conductor

Picture 5: The markings on the cable lug provideinformation relating to the crimps, the manu-facturer, cross section and allocation of cable.

Source: Klauke

Sour

ce: K

lauk

e

Picture 6: High quality aluminium cable lugs come with a special compound whichimproves the contact properties and ensuresa perfect electrical connection.

Picture 8: Normally the aluminiumsection (right) has a larger diameterthan the copper section (left) to equalizethe poor conductivity of aluminium.

Sour

ce: K

lauk

e

Picture 7: Aluminium and copperconductors with different crosssections are being connectedusing reduction sleeves.

Greenlee CSJ-100 open jaw meter

Non-contact voltage detection in the narrowest spaces – the Greenlee CSJ-100 digital open jaw meter makes it possible.

It is designed for AC current measurements of up to 200 A AC and for AC and DC voltages up to 1000 V. It meets the requirements of safety category IV up to 600 V or category III up to 1000 V.

Additional product features are the data-hold-function for recording measurements, the automatic power-off for longer battery life, an audible continuity check and a diode test.

www.klauke.com

KLA09-002_Anz_CSJ100_A5q_eng_RZ.1 1 26.01.2009 16:10:45 Uhr

minium / copper compression cable lugsare the same as those for pure alu-minium versions.

Quality products manufactured bymarket leaders such as Klauke feature aconsistent material thickness, exactdiameters and correct fit are a prereq-uisite for ensuring high safety stan-dards are always met. Like aluminiumcompression cable lugs conforming toDIN 46239, aluminium/copper compres-sion cable lugs feature a barrier designallowing the use of oil soaked andpaper insulated cables which preventsoil leakage.

Aluminium conductors at a glance

Aluminium conductors are available infour different versions which require insome cases special processing. Theseare ((sseeee ppiiccttuurree 44)).

• round solid conductor(re)• sector solid conductor(se)• round stranded conductor (rm)• sector stranded conductor (sm)

These abbreviations will be foundnext to other markings on all Al/Cucompression cable lugs and identifywhich conductors will suit the appropri-ate cable lug. ((sseeee ppiiccttuurree 55)).

Markings on the product providethe installer with essential informa-

tions. Marking “16 KL25 150 rm/sm 185re/se” stands for

• 16: Metric bolt size for connectingbolt – size M16.

• KL: Manufacturer (in this case Klauke)

• 25: Die code • 150: Cross section of conductor

in mm2

• rm/sm: for round multi-stranded andsector stranded conductors

• 185: Cross section of conductor in mm2

• re/se: for round single stranded solidand single sector solid conductors

The die code also needs special con-sideration. For an accurate and safecrimp the die reference should be thesame as that shown on the cable lug.The die code can be seen on the dieface as a mirror image so that aftercompression the die code is visible onthe cable lug for final control andinspection.

For an accurate processing of Al/Cucompression cable lugs it is generally

4 de Special

Acopper-aluminium connectionis used for instance in an indus-trial estate where local business

use copper supply cables which arethen fed off an aluminium ring main.But also in electrical substations it isnecessary to connect aluminium con-ductors to copper bus bars. The mainproblem here is that connecting alu-minium and copper is not straight-forward. To ensure a safe and correctconnection the use of special alu-minium/copper cable lugs and connec-tors are essential. ((PPiiccttuurree 11)).

Aluminium-Copper:A problematic connection

Generally aluminium is a reactive mate-rial that oxidizes easily, but in practice ithas proved to offer good corrosionresistance. This characteristic is due to achemical reaction that takes placewhen in contact with atmospheric oxy-gen resulting in a very thin but also

very resistant oxide layer being formed.(oxide barrier)

When metals are connected to thosewith a higher electrical potential suchas copper in the presences of an elec-trolyte (condensed water) will result inan electrochemical reaction takingplace. During this process the differ-ences caused in electrochemical poten-tial can have a significant impact.

An electrical circuit is generated bythe copper electrode (anode), the elec-trolyte (water) and the aluminium elec-trode (cathode). The voltage generatedin this copper and aluminium circuit“semi metallic” state results in a shortcircuit.

As a result of the current generatedthe Aluminium surface breaks downcausing the metal to electrolyticallydecompose. This destructive process isvisible as a kind of blooming oxidationand begins already with the existenceof tiny copper particles on the alu-minium; this ongoing reaction itselfdoes not cause the copper to corrode.In an electrical connection however theresistance is increased leading toincreased temperatures which then inthe worst case lead to a fire.

Therefore when connecting copperand aluminium it is important to ensure

that no moisture can enter the connec-tions. In an environment where mois-ture is present the contact pointsbetween the copper and aluminiumneed to be protected by using accurateoperating procedures. ((sseeee ppiiccttuurree 22)).Primarily this requires the use of alu-minium/copper cable lugs and connec-tors. Due to the design of these lugsareas where moisture could accumu-late and where the oxidation processcould start have been avoided. For thisreason aluminium/copper cable lugsand connectors are specified for the usein off-shore wind power stations.

Aluminium/copper compressioncable lugs

Leading manufacturers of high qualitycompression cable lugs for connectingaluminium connectors with copper busbars ((sseeee ppiiccttuurree 33)) consist of an elec-trolytic aluminium (E-Al) compressionand are joined to a copper palm (to EN13600).

The available cross sections rangefrom 16 mm2 up to 400 mm2. The fieldof application covers in principle allnon-tension connections of aluminiumcables acc. to DIN 48201, part 1, andaluminium ropes acc. to DIN 50182.Specifications and processing of alu-

2 de Special

Copper due to its outstanding electrical properties are always

the first choice when selecting a conductor for an electrical

connection. A practicable alternative in many cases is aluminium

particularly because of its low weight and easy application. In

practice however the electrician can find it challenging to connect

both these materials in a professional manner.

Accurately connectingcopper and aluminium

Electroinstallation IN BRIEFCopper and Aluminium conductorsare difficult to connect to each other.It is therefore necessary to avoid theingress of moisture at all costs. Forthese applications special cable lugsare needed and accurate operatingprocedures should be adhered to.

Electroinstallation

Picture 1: Use of an incorrect crim-ping die and/or an incorrect crimpwill result in an over compression(right) or an under compression(left) and in the worst case in fire.

Sour

ce: K

lauk

e

Picture 2: The construction of Al/Cucable lugs prevents any gaps which

would allow the accumulation ofliquid to take place which would start

the oxidation process.

Sour

ce: K

lauk

e

Picture 3: A professional connection of an aluminium conductor with acopper busbar is done by means of an aluminium cable lug and a copperpalm.

Sour

ce: K

lauk

e

recommended to use hexagon crimp-ing dies acc. to DIN 48083 part 4. Inorder to ensure an accurate and profes-sional crimp avoiding over or undercompression is the use of appropriatecrimping tools. Poor crimps can result inan increase in joint resistance and tem-peratures that can lead to fires. To pre-vent such issues Klauke solely recom-

mend using the manufacturers crimp-ing tools to crimp their cable lugs.

For instance the special crimpingdies for aluminium have a crimp widthof 7 mm, i.e. 2 mm wider than thecrimping dies for copper cable lugs andconnectors. This, however, only appliesto 60 kN crimping dies. The reason forthis is that dies with a larger crimpwidth are able to connect a wider con-ductor surface area with the cable lugsand balance the poor conductivity ofaluminium. To easily identify which die

should be used, Klauke manufacturesaluminium dies in a silver colour while dies for copper are yellow-goldcoloured.

Connecting compound for alumi-nium connecting material

All cable lugs and connectors for alu-minium conductors come with a specialcompound ((sseeee ppiiccttuurree 66)). This aggra-vates the non-conductive oxide layerwhich is quickly formed on the surface.This compound improves the contactproperties and enables a perfect elec-trical connection, and also prevents fur-ther oxygen penetrating the contactjoints where further oxidation couldtake place. To maintain the functionalcapability of the compound all leadingbrand cable lugs are sealed with a plas-tic plug to prevent the compound fromdrying-out and leakage.

Al/Cu Connectors

For a correct connection of aluminiumand copper conductors leading manu-facturers such as Klauke offer reductioncompression joints with a cross sectionrange from 10 mm2 up to 300 mm2.((sseeee ppiiccttuurree 77)). These products servemainly the reconstruction of powerlines, i.e. non-tension connections ofaluminium conductors acc. to DIN EN60228 resp. aluminium wires acc. to DINEN 50182 with copper cables acc. to DIN48201, part 1 and copper conductorsacc. to DIN EN 60228. These compres-sion joints consist of interconnectedaluminium (E-Al) and copper parts (acc.to EN 13600).

Normally the aluminium part of the cross section has a much largerdiameter ((sseeee ppiiccttuurree 88)) to compen-sate for the poor conductivity of alu-minium. As with the cable lugs here tooplastic plugs are used to preventdrying-out and leakage. Important: The use of Al/Cu compression jointsrequires that the correct processingguidelines for copper and aluminiumare observed.

Consequently the aluminium sectionneeds to be crimped like an aluminiumcompression cable lug (see above).Characteristically for Al/Cu compressionjoints are the different crimping markswhich are 7 mm on the aluminium sec-tion and 5 mm on the copper part forcrimping dies up to 60 kN.

Picture 4: Various shapes of aluminiumconductors

Sour

ce: K

lauk

e

Sour

ce: K

lauk

e

re – round solid conductor

se – sector solid conductor

rm – round stranded conductor

sm – sector stranded conductor

Picture 5: The markings on the cable lug provideinformation relating to the crimps, the manu-facturer, cross section and allocation of cable.

Source: Klauke

Sour

ce: K

lauk

e

Picture 6: High quality aluminium cable lugs come with a special compound whichimproves the contact properties and ensuresa perfect electrical connection.

Picture 8: Normally the aluminiumsection (right) has a larger diameterthan the copper section (left) to equalizethe poor conductivity of aluminium.

Sour

ce: K

lauk

e

Picture 7: Aluminium and copperconductors with different crosssections are being connectedusing reduction sleeves.

Greenlee CSJ-100 open jaw meter

Non-contact voltage detection in the narrowest spaces – the Greenlee CSJ-100 digital open jaw meter makes it possible.

It is designed for AC current measurements of up to 200 A AC and for AC and DC voltages up to 1000 V. It meets the requirements of safety category IV up to 600 V or category III up to 1000 V.

Additional product features are the data-hold-function for recording measurements, the automatic power-off for longer battery life, an audible continuity check and a diode test.

www.klauke.com

KLA09-002_Anz_CSJ100_A5q_eng_RZ.1 1 26.01.2009 16:10:45 Uhr

The procedure for the copper sec-tion is absolutely identical as on coppercompression cable lugs. The crimpingmarks on the product give detailedinformation as to origin and applica-tion of the Al/Cu compression joints.The marking “KL14 50 rm/70 re/se” sig-nifies

• KL: Manufacturer (in this caseKlauke)

• 14: Die code• 50: Cross section of designed

conductor in mm2

• rm/sm: for round stranded andsector stranded conductors

• 70: cross section of solid conductor in mm2

• re/se: for round solid and sector solidconductors

The marks on the copper sectionalso indicate the correct procedure. Thestandard suggests crimping dies acc. toDIN 48083 part 1, 3 and 4 for solid-, fineand fine stranded conductors; forbraided round wires the standardrefers to specifications of the manufac-turer. Generally Klauke recommendsusing hexagon crimping dies acc. to DIN48083 part 4 for processing the coppersection of their compression joints.

Advice: When using crimp connec-tions in the ground it should be strictlyobserved that the connecting jointsshould be protected against moisture.((PPiiccttuurree 99)). For this application Klaukerecommends use of cast-resin joints.

For the application of Al/Cu com-pression joints and cable lugs the fol-lowing should also be considered:These products should not be exposedto bending stresses which could frac-ture the contact point. Application onoverhead lines is therefore excluded.

Preview: Crimp profiles at a glance

With a further feature story in one ofthe next issues of “de” we close theseries on cable lugs and connectors.This article will deal with the variouscrimp profiles which correct selectiondepends very much on materials andcable types used.

Lutz Remmel, Product Manager Electrical connecting systems,

Gustav Klauke GmbHwww.klauke.com

MEHR INFOS

Contribution on this issue http://www.de-online.info/archiv/2008/01-02/index.php?Page=elektroinstallation04.html• Which cable lug for which appli-

cation?, “de” 1-2/2008, S.33 http://www.de-online.info/archiv/2008/08/index.php?Page=elektroinstallation02.html• Cable lugs for special applications,

“de” 8/2008, S.27http://www.de-online.info/archiv/2008/17/index.php?Page=elektroinstallation02.html• Best Practise for Installation of

Aluminium Connectors, „de“17/2008, S.26

Book on this issueSchmolke, Herbert: Selection anddesign of cables and conductors2007.2, revised and extended edition.120 pages, paperback, with CD Rom,18€, ISBN 978-3-8101-0263-8, www.de-online.info/ shop/fachbuecher/schmolke_kabel.html

www.de-online.info

Der Elektro- und Gebäudetechniker

de Special 22/2008

ORGAN DES

ZVEH

ELECTROINSTALLATION:

Accurately connecting copperand aluminium

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

Engineers professional tool-bag

All in one. One for all.

For more information please visit www.klauke.com

KL390IS (6-pieces) KL130PM1IS KL130PM2IS

KL044200IS KL050205IS KL020165IS

KL745HK KL710 KL403

The quality bag comes with genuine

Klauke tools.

The ideal companion for electricians, fitters or installation engineers:

The Klauke Engineers professional tool-bag has space for the complete

tool range and provides safe storage of laptop, documents, mobile phone or

business cards. The clever compartmentation as well as removable single

components turn the tool-bag into a very flexible system meeting all

day-to-day requirements.

Electroinstallation

5 de Special

Picture 9: When used in theground cast-resin joints protect

the connections against moisture.It is important to consider that the

connection is not subject tobending to avoid the risk of frac-

ture. Sour

ce: K

lauk

e

BRD

ESO

ND

ER22

2008

GB

10.

000

02/0

9 I

The procedure for the copper sec-tion is absolutely identical as on coppercompression cable lugs. The crimpingmarks on the product give detailedinformation as to origin and applica-tion of the Al/Cu compression joints.The marking “KL14 50 rm/70 re/se” sig-nifies

• KL: Manufacturer (in this caseKlauke)

• 14: Die code• 50: Cross section of designed

conductor in mm2

• rm/sm: for round stranded andsector stranded conductors

• 70: cross section of solid conductor in mm2

• re/se: for round solid and sector solidconductors

The marks on the copper sectionalso indicate the correct procedure. Thestandard suggests crimping dies acc. toDIN 48083 part 1, 3 and 4 for solid-, fineand fine stranded conductors; forbraided round wires the standardrefers to specifications of the manufac-turer. Generally Klauke recommendsusing hexagon crimping dies acc. to DIN48083 part 4 for processing the coppersection of their compression joints.

Advice: When using crimp connec-tions in the ground it should be strictlyobserved that the connecting jointsshould be protected against moisture.((PPiiccttuurree 99)). For this application Klaukerecommends use of cast-resin joints.

For the application of Al/Cu com-pression joints and cable lugs the fol-lowing should also be considered:These products should not be exposedto bending stresses which could frac-ture the contact point. Application onoverhead lines is therefore excluded.

Preview: Crimp profiles at a glance

With a further feature story in one ofthe next issues of “de” we close theseries on cable lugs and connectors.This article will deal with the variouscrimp profiles which correct selectiondepends very much on materials andcable types used.

Lutz Remmel, Product Manager Electrical connecting systems,

Gustav Klauke GmbHwww.klauke.com

MEHR INFOS

Contribution on this issue http://www.de-online.info/archiv/2008/01-02/index.php?Page=elektroinstallation04.html• Which cable lug for which appli-

cation?, “de” 1-2/2008, S.33 http://www.de-online.info/archiv/2008/08/index.php?Page=elektroinstallation02.html• Cable lugs for special applications,

“de” 8/2008, S.27http://www.de-online.info/archiv/2008/17/index.php?Page=elektroinstallation02.html• Best Practise for Installation of

Aluminium Connectors, „de“17/2008, S.26

Book on this issueSchmolke, Herbert: Selection anddesign of cables and conductors2007.2, revised and extended edition.120 pages, paperback, with CD Rom,18€, ISBN 978-3-8101-0263-8, www.de-online.info/ shop/fachbuecher/schmolke_kabel.html

www.de-online.info

Der Elektro- und Gebäudetechniker

de Special 22/2008

ORGAN DES

ZVEH

ELECTROINSTALLATION:

Accurately connecting copperand aluminium

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

Engineers professional tool-bag

All in one. One for all.

For more information please visit www.klauke.com

KL390IS (6-pieces) KL130PM1IS KL130PM2IS

KL044200IS KL050205IS KL020165IS

KL745HK KL710 KL403

The quality bag comes with genuine

Klauke tools.

The ideal companion for electricians, fitters or installation engineers:

The Klauke Engineers professional tool-bag has space for the complete

tool range and provides safe storage of laptop, documents, mobile phone or

business cards. The clever compartmentation as well as removable single

components turn the tool-bag into a very flexible system meeting all

day-to-day requirements.

Electroinstallation

5 de Special

Picture 9: When used in theground cast-resin joints protect

the connections against moisture.It is important to consider that the

connection is not subject tobending to avoid the risk of frac-

ture. Sour

ce: K

lauk

e

BRD

ESO

ND

ER22

2008

GB

10.

000

02/0

9 I