Earth rods and their fittings are used to provide the interface to ground in all soil conditions in order to achieve satisfactory earthing systems in overhead and underground electricity distribution and transmission networks – providing high fault current capacity on low, medium and high voltage substations, towers and power distribution applications.
Convenient to install where the subsoil condition is free from rock and boulders the earth rod or group of copper rods can be surrounded or backfilled using a low resistance material such as Bentonite.
Depending on the corrosive condition and electrical conductivity of the ground condition the earth rod can be specified to achieve safe, reliable and long term earthing protection – the mechanical strength of the rod must withstand the abrasion and stress endured while installing with an electric or pneumatic driving rod hammer; the head of the earth rod should not “mushroom” or spread when driven.
The earth rods are extendable by design and used with copper couplers to inter-connect several rods to achieve the required driving depth – the rod couplers provide permanent electrical conductivity and the longer copper earth rods access lower resistivity soils at lower depths.
Vertically driven earth rods are the most effective electrode for use in typically small area substations or when low soil resistivity ground conditions, into which the rod can where the rod can penetrate, lies beneath a layer of high soil resistivity.
TYPES OF EARTH ROD
- Copper bond Threaded Earth Rods
- Solid Copper Earth Rods
- Stainless Steel Earth Rods
- Galvanized Steel Earth Rods
Copper is the optimal choice of earth electrode material and underground conductor – solid copper is recommended for high fault current installations whereas copper bonded rods are usually installed for smaller sections.
Copper bonded steel core earth rods are the most specified due to electrical and mechanical strength, resistance to corrosion as comparatively lower cost compared to solid copper or stainless steel types – the lowest cost galvanized rods for usually installed non-critical, short-term or temporary earthing requirements.
|TYPES OF EARTH ROD||FEATURES & BENEFITS|
|COPPERBOND||Optimum Economic Efficiency * High Corrosion Resistant * Very High Tensile Strength * Extendable|
|SOLID COPPER||Excellent Corrosion Resistance * Aggressive Soil Applications (eg high salt) * Extendable|
|STAINLESS STEEL||Maximum Corrosion Resistance * Resist Galvanic Corrosion * Highest Material Cost * High Life Expectancy|
|GALVANIZED STEEL||Lowest Electrical Conductivity * Lowest Cost * Lowest Corrosion Resistance * Poor Current Carrying Capacity|