Cable Jointing Copper To Aluminium Conductors Correctly Using Resin Cable Joints

Published 04 Feb 2019

Resin Cable Joints

  • uploaded by Chris Dodds - Thorne & Derrick Sales & Marketing Manager

What To Consider When Jointing Cables With Various Types Of Conductor

A common question posed by LV cable jointers concerns the conductor jointing of dissimilar metals or core construction in underground cable joints.

Thorne & Derrick can make recommendations to overcome the potential problems encountered when cable jointing aluminium to copper cables and provide guidance on best practice to avoid potential corrosion problems within resin cable joints up to 3.3kV.

Typical applications could involve the transition cable jointing of BS5467 XLPE SWA copper conductor to existing imperial PILC SWA aluminium conductor cables in an underground application (or direct burial) in a cable trench.

Copper Aluminium Conductors Cable Joints

3.3kV cable joints utilising heat shrink technology and mechanical shearbolt connectors are available for the jointing of power cables up to 3.3kV in accordance with IEC 60228 and IEC 60502 – this includes the cable jointing of circular to sectoral conductors.

Similarly mechanical style conductor connectors are commonly used to joint conductors with divergent cross section areas – often called “reducer connectors” the shearbolt type connectors permits the “step-down” jointing of cables within the range accommodation of the connector.

Where crimp connectors from manufacturers such as Cembre are “dead-sized” and specified to connect “like-for-like” sized metric conductors the mechanical connector allows improved cable application ranges.

Mechanical shearbolt connections, such as Pfisterer, provide quick to install options for jointing dissimilar conductor types and constructions, whether circular, sectoral, stranded or solid – suitable for power systems at 3.3kV, 11kV, 33kV and up to 66kV.

Pfisterer Sicon connectors are used by Jointers to provide immediate and reliable connection of all types of cable conductors.

Pfisterer Sicon

Video. Pfisterer Sicon Connectors – Safe & Reliable Cable Conductor Jointing. 

The range-taking nature of mechanical connectors allow the jointing of different cross section area conductors together without resort to crimp tooling.

Cable Corrosion Repair

Read Blog: Overcoming Cable Corrosion On Steel Wire Armoured & Braided Cables

2 Factors Associated With Conductor Corrosion

1. Atmospheric action

2. Galvanic action

For atmospheric action to result in cable corrosion both moisture and oxygen must be present within the cable joint.

Galvanic action results in corrosion when 2 dissimilar metals in an electrolytic series, such as copper and aluminium, are in physical contact.

This contact could be caused by the compression or crimping of aluminium and copper conductors together causing any moisture present to act as an electrolyte. In this situation, the copper becomes a cathode and receives the positive charge and the aluminium becomes the anode receiving a negative charge.

The resultant current flow attacks the aluminium leaving the copper unharmed.

LV Cable Joints

Cable joints utilising Scotchcast Resins are trusted to provide uninterrupted power supply to electrical infrastructure in industrial and hazardous area locations – specialist application and chemical formula resins are available including hydrocarbon resistant, flame retardant, submersible and zero halogen types.

Cable Jointing For Industrial & Hazardous Areas Up To 3.3kV

To avoid bi-metallic corrosion caused by the connecting of the copper to aluminium conductors, 3M Scotchcast LVI resin cable joints can be used – 3M cable joints are fully encapsulated with either 3M Scotchcast 470W Resin for industrial cable installations or 3M Scotchast 1402FR Resin for cables being jointed in hazardous areas.

The pouring of the cable jointing resin into the shell eliminates air voids driving out moisture eliminating the basic requirements for galvanic reaction and cable corrosion to occur.

3M Scotchcast Resin LVI-1 Type Cable Joints For Low Voltage Power Cables

LV Cable Joints (Low Voltage Cables)

Thorne & Derrick stock and distribute LV Joints in Cold Shrink, Heat Shrink or Resin Cast technologies – multicore and multi-pair cable joints are available for immediate backfill and energisation of Low Voltage power, control and instrumentation cables 600V/1000V 3.3kV.

Complete range of LV Cable Accessories  ➡

Cable Breakouts | Cable Caps | Cable Lugs | Cable Cleats | Cable Trough | Cable Duct | Feeder Pillars | for 11kV/33kV/66kV networks see MV HV Joints & Terminations

Joints Terminations Connectors

Pfisterer | Nexans Euromold | Prysmian | Cable Joints & Terminations MV HV

Cold Shrink

Cold Shrink by 3M | Joints | Abandonment | Terminations | Low Voltage LV Cables

Further Reading