Overcoming Cable Corrosion On Steel Wire Armoured & Braided Cables

By Chris Dodds on 24th January, 2017

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Overcoming Cable Corrosion On Steel Wire Armoured & Braided Cables

3M Electrical Products provide an extensive range of Cable Repair solutions for the utilities, power, solar, construction, rail, mining, offshore, oil, gas and petrochemical industries.

Cable repair solutions are available for low and medium voltage cables suffering advanced cable damage caused by atmospheric steel corrosion - onshore and offshore galvanised wire armour and wire braided cables are especially vulnerable.

The Problem

Cable Corrosion

Advanced Cable Corrosion & Degradation - the pictured low voltage cables evidently have serious damage caused by long-term corrosion effects. The cable sheathing has been agressively damaged and stripped back down to the galvanised steel wire armours. Steel typically corrodes or rusts rapidly in moist or humid conditions and the rate of corrosion accelerates with exposure to salt water, for instance in the marine and offshore industry.

The cable sheath should provide both waterproof and corrosion protection to the steel wire armours and copper conductors - in this case there is an urgent demand to prevent further corrosion damage to both the accessible and inaccessible cables strapped to the cable tray.    

Cable Repair Damaged 

The complexity of the cable repair is compounded two-fold : the area is a "no-heat" zone therefore traditional heat shrink cable repair kits are precluded from consideration. Furthermore due to the brittleness of the cables, resultant from significant corrosion damage, it was not an option to man-handle and subject the cables to movement and strain. 

The Solutions3M Scotchrap 50 Corrosion Protection Tape 

2 solutions to suppress future cable corrosion using 3M Electrical Cable Repair products :

  • Accessible Cables - 3M Scotchrap 50 Tape provides advanced corrosion protection to cables exhibiting excellent resistance to abrasion, moisture, corrosive salt water, soil acids, alkalis and salts. 

3M Scotchrap tapes are UV resistant and also resist impact punctures and tears with a very high weather and corrosion proofing performance for use on underground cables. 3M Scotchfil Electrical Insulation Putty can be used to build-up irregular surfaces to provide a smooth, waterproof taping surface around cables where there is localised pitting type corrosion. 

 

  • Inaccessible Cables - where cable access is limited 3M 1603 Insulation Spray can be used to protect cables and surfaces (including galvanised steel cable tray) against weather, moisture, corrosion, oil, alkalies and acids. 3M 1603 sprays provide easy access to hard-to-reach spots. eabling versatile on-site cable repairs without specialist tooling or requirement to disconnect or isolate cable circuits. 3M insulating spray sealers to spray over insulation on wire and cable splices, as a general-purpose sealer, or for touch-up insulation on motor windings and frames. Precautionary and first aid information for this product may be found in its Material Safety Data Sheet and on the product container.

Another type of cable failure is evidenced by visual indication of burning or arcing on the surface of the semiconductive layer of medium voltage cables. If the burning or arcing becomes extensive, the MV cable can fail from the outside in (pictured below).  The MV cable failure cause was determined to be a damaged cable sheath or jacket, which created a flowpath for corrosive ground water to penetrate the cable and cause severe corrosion to the metallic shield.

Cable Corrosion Cable Repair

Some Further Reading : Corrosion Types Encountered With Power Cables : Underground Cables and Anodic Corrosion (Stray DC Currents), Cathodic Corrosion, Galvanic Corrosion, Chemical Corrosion, AC Corrosion, Local Cell Corrosion. By Edvard Csanyi (Electrical Engineering Portal EEP).

Power Cable Corrosion

Whatever the cable condition or type of installation, 3M can provide innovative cable corrosion protection solutions based on tape, resin, heat shrink, cold shrink or spray based technology. 

  • Further reading

Cable Cleats & Galvanic Corrosion - Ellis Patents Cable Cleats

A Shutdown Postmortem - Reducing Cable Failures Caused By Sub-Standard Cable Jointing

Cable Fault Analysis : 5 Case Studies - Heat Shrink Cable Joints & Cable Terminations

 

Thorne & Derrick Specialist Electrical Distributor

Established since 1985, T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Pulling & Installation Equipment - contact us today for a competitive quotation.

Key Products : MV Joints & Terminations, Cable Cleats, Duct Seals, Cable Transits, Underground Cable Protection, Jointing Tools, Feeder Pillars, Cable Duct, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Protection & Fusegear.

Distributors for : 3M, Pfisterer, Nexans Euromold, Elastimold, Catu, Roxtec, Emtelle, Centriforce, Lucy Zodion, Alroc, Hivotec, Cembre, Prysmian, Ellis Patents, ABB & Furse.

Cable Joints Terminations Tools Cleats

 

Invitation

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Discussion subjects include cable installations, cable jointing, electrical substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV.

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Category:  LV Cable Jointing & Terminating

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