Grounding System Installation

Grounding System Installation

Copyright: © 2018 |Pages: 34
DOI: 10.4018/978-1-5225-3853-0.ch004
OnDemand PDF Download:
$30.00
List Price: $37.50

Abstract

This chapter includes the following points: Methods of installing ground rods, chemical ground rod, chemical treatment of soil lessens seasonal variation of electrodes, soil treatment, trench method of soil treatment, lengthen of the earth electrode in the earth, use multiple rods, Ground Enhancement Material, (GEM), grid installation and conductor materials of grounding system. This chapter draws attention also to the following points: ground rod life expectancy, ground rod annual cost, grounding rods accessories and applications, grounding rods installation methods, chemical grounding rods, copper versus stainless steel electrodes, variation on grounding resistance system by seasonal variation effects and finally how to improve the earthing resistance.
Chapter Preview
Top

Methods Of Installing Grounding Rods

Grounding Rods

Ground rods are often selected on the basis of their resistance to corrosion. The other major factor is the cost. All too often, 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 steel 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 galvanized steel rods. In addition to this, solid copper rods are not suited to deep driving or even driving short lengths into hard ground, without bending.

As a compromise, steel cord ground rods, swaged in a copper or stainless steel sheath were developed. These ground rods are much less expensive than their solid counterparts. They are capable of being deep driven. However, the sheath of this rod type has been known to slip or tear, particularly the copper version. Once this sheath has been damaged, the integrity of the entire electrode is at risk. (Figure 1) shows copper bonded ground rod versus galvanized ground rod.

Figure 1.

Copper bonded ground rod versus galvanized ground rod

The copper bonded ground rod has an electrolytic coating of copper deposited over a layer of nickel. This process ensures a long lasting, molecular bond between the copper layer and the steel core. Recommends copper bonded ground rods because the copper coating will not slip or tear when driven nor will it crack if the rod is bent. The tough, carbon steel core has good characteristics for deep driving. Copper bonded ground rods have a high resistance to corrosion and provide a low resistance path to ground.

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 is a better proposition. Stainless steel 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. (Figure 2) gives Photo shows two ground rods subjected to the same pressure load test.

Figure 2.

Photo of two ground rods subjected to the same pressure load test

The copper bonded ground rod, shown on the left, will bend without tears, cracks or folds, to the outer sheath. The inferior copper clad rod shown on right, has developed cracks and creases to the outer sheath, which will significantly reduce its serviceable life and put the integrity of the entire electrode at risk. (Figure 3) shows the ground rod life expectancy and (Figure 4) shows the ground rod annual cost for different rods types.

Figure 3.

Ground rod life expectancy

Figure 4.

Ground rod annual cost

Top

Grounding Rod Accessories And Application

Driving Sleeves

The driving head fits over the ground rod to protect the rod end from “mushrooming” as the ground rod is driven into earth. See (Figure 5)

Figure 5.

Driving sleeves

Complete Chapter List

Search this Book:
Reset