Nexans GPH Cable Connectors & The Fall Of The Berlin Wall

By Chris Dodds on 11th November, 2015

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GPH Mechanical Cable Connectors & Mechanical Cable Lugs - Shear Off Bolt Technology.

The fall of the Berlin Wall paved the way for German reunification while ending the division between the capitalist West and communist East.

The collapse of the iconic concrete barrier heralded public jubilation and Berliners partied long into the night.

Politicians then began debating the ramifications of political and economic unity.

Meanwhile, German utilities started comparing cables and tackling the complex question of electrical unification of the two former Cold War rivals.

So let us explain how the fall of the Berlin Wall highlighted the urgent need for a technological revolution in the approach to jointing cables.

Picture : 1989 The Fall of the Wall.

Photograph by Gerard Malie/AFP via Getty Images.

When West German power utility companies took over the energy network from German Democratic Republic (GDR) in the former Soviet occupation zones, the cable jointers encountered a wide variety of cable conductor shapes (circular and sectoral), types (copper and aluminium) and sizes (anything from 1.5sqmm to 1000sqmm).

Back then, West German power utilities used hexagonal compression technology for cable jointing following a DIN standard - the main disadvantage of this compression crimping technology was that crimp ferrules and crimp lugs had to be adapted to precisely the conductors being jointed, often very different and unfamiliar to West German utilities and cable jointers.

The result being that utilities were unable to easily join cable conductors and there was no compression or crimping solution that could cater for crossover of all cable standards, whether low voltage, medium voltage or high voltage. This resulted in a unique opportunity to introduce a new shear off bolt technology which could joint all cable standards and joint two different cable standards and cable sizes.

The first generation of “GPH Single Shear Off Technology”  allowed precision and consistent contact force with which the conductor is installed into the barrel of the mechanical connector providing:

• a simple and fail safe solution without use of special jointing tools

• a connection that guaranteed the correct contact force within the barrel by shearing off the hexagon head at the correct torque level every time

• optimized contact regardless of the cable type or make-up e.g. solid, stranded, compacted, round or sector

• suitability for a wide cross sectional range of conductors

The second generation of “GPH Double Shear Off Technology” using an Allen Key for a 2 Step installation provided suitability for a wider cross sectional range of conductors. Further development for medium voltage applications required reduction of “excess length” of the shear off bolts.

The third generation of “GPH Multi Share Off Bolt Technology” once again improved the technical performance. This design was patented in 1998 and is used in all GPH M- and C - Series products.

Market demand, to reduce stock cost, drove the need to widen the cross section range. This brought new challenges into the design of mechanical connectors when considering the minimum and maximum range of a particular shear bolt and the management of excess length of the shear bolt itself. It is physically intuitive that small cross sections should be connected with lower forces than larger ones. Exposing small conductors to high contact forces causes inevitable partial cross section reduction.

See : Nexans GPH 33kV Medium Voltage Cable Connectors & Lugs (800-1200sqmm)  

 

• Further reading :

Jointer Training Video : Nexans AIN20 24kV Slip-On Indoor High Voltage Cable Terminations 

Jointer Training Video : Nexans AFNP36 33kV Slip-On Outdoor High Voltage Cable Terminations 

 

 

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GPH Mechanical Cable Lugs Connectors

Category:  HV Cable Jointing & Terminating

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