Earth Electrodes are selected on the basis of their resistance to corrosion. The other major faction in selection is cost parameter. The cost of a product is seen as the initial up front price, but the real cost is determined by the serviceable life of the ground rod.
Galvanized Iron pipe rods are one of the cheapest electrodes available. However, they are not the most cost effective since they have a relatively short service life.
Solid copper and stainless steel rods have a long service life. However, they
are considerably more expensive than GI pipe rods. In addition to this, solid copper rods
are not suited to deep driving into hard ground due to the likelihood of
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copper bonded ground rods is recommend over copper clad electrodes because the copper coating will not slip or tear when driven nor will it crack if the rod is bent.
Copper bonded earth rods feature high resistance to corrosion, provide a low resistance path to ground and have good characteristics for deep driving.
The Stainless Steel Option:
It is important to note that certain soils and land fill areas may not be compatible with copper. In these situations, stainless steel represents a better option.
Stainless steel earth rods may also be an alternative, where structures or components, such as steel towers, poles or lead sheathed cables are in close proximity to an array of ground electrodes.In these circumstances, consideration must be given to the consequence of galvanic corrosion. The high cost of stainless steel rods prohibits their widespread use.
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