What is an earthing rod?
earthing rods or ground electrodes are usually solid rods or pipes driven into the ground to make an earth connection, usually made of copper. In eastern Europe aluminium was frequently used. If the use of this system is not practical, a waterpipe connected to an underground supply can be used as electrode. 3.3K views.
What is the purpose of earthing?
The purpose of earthing is to minimize risk of receiving an electric shock if touching metal parts when a fault is present.
Why is earthing important?
The principle behind earthing is to provide an alternative path to earth to prevent a person from being electrocuted. The impedance of the fault path will determine the fault current level of the system. This is important to calculate protection times, step voltages, touch voltages, earth potential rise etc.
How is earthing accomplished?
Earthing has been accomplished through bonding of a metallic system to earth. It is normally achieved by inserting ground rods or other electrodes deep inside earth. Earthing is to ensure safety or Protection of electrical equipment and Human by discharging the electrical energy to the earth.
What is grounding in electrical?
Grounding refers the current carrying part of the system such as neutral (of the transformer or generator). Because of lightning, line surges or unintentional contact with other high voltage lines, dangerously high voltages can develop in the electrical distribution system wires.
Why is the Earth used as a ground conductor?
Earth is used for the safety of the human body in fault conditions while Grounding (As neutral earth) is used for the protection of equipments. The ground conductor provides a return path for fault current when a phase conductor accidentally comes in contact with a grounded object.
What is green wire?
Generally green wire is used for this as a nomenclature. Under fault conditions the non-current carrying metal parts of an electrical installation such as frames, enclosures, supports, fencing etc. may attain high potential with respect to ground so that any person or stra. Continue Reading.
What Are Earth Rods?
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.
Why are earth rods installed?
in arrears where the soil is made up primarily of slate, shale or rock)”ƒ, vertical earth rods are installed to reduce resistance.
What is a vertically driven earth rod?
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.
What earthing material is used to surround copper rods?
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 earthing material such as Bentonite.
How does change of earth rod diameter affect resistance?
Change of earth rod diameter has marginal impact on the overall value of resistance with the size more determined by the mechanical strength of the rod to withstand being mechanically driven when deep earth rods are required e.g. to depths of 20 metres or more.
Where are earth rods located?
Earth rods or copper electrodes are commonly installed into the concrete floor of the primary substation building to protect gas insulated switchgear (GIS) and earth bars are positioned either within or buried immediately outside the building walls – the electrode would be located close to either i) circuit breakers ii) cable sealing ends iii) SF6 or air bushing iv) instrument transformers or v) substation busbars.
How are copper earth rods driven?
The rods are driven vertically into the ground and earth resistance is measured as each section is installed.
What is earth rod?
Earth rods are essentially used as their fittings provide the interface to ground in all soil conditions in order to achieve a quality earthing systems in the overhead and underground electricity distribution and transmission networks, this provides high fault current capacity on low, medium and high voltage substations, towers and power distribution applications.
When are earth rods installed?
Earth rod electrodes are installed during the civil engineering works associated with substation construction – soil resistivity readings are taken and if “greater than 200m , basically, vertical earth rods are installed to reduce resistance. Note consult local UK DNO or utility recommendations which vary according to engineering standards and preferences.
What is the most effective electrode for substations?
Vertically driven earth rods tend to be the most effective electrode for usage in typically smaller areas of substations or when low soil resistivity ground conditions, into which the rod can where the rod can penetrate, lies underneath a layer of high soil resistivity. Earth Rods Diameter v Length. A frequently made misconception is that there is ...
How does change of earth rod diameter affect resistance?
Change of earth rod diameter has marginal impact on the overall value of resistance with the size determined by the mechanical and structural strength of the rod to withstand being mechanically driven when deep earth rods are required e.g. to depths of 20 metres or more.
What is the best material for earth electrodes?
Copper is the best choice for earth electrode material as an underground conductor, a solid copper is recommended for high fault current installations whereas copper bonded rods are usually installed for smaller sections.
How much does doubling the diameter of a rod increase resistance?
The resistance value is only decreased by 9.5% by doubling the diameter of the rod, which means increasing the weight and the cost of the rod by approximately 400%. Thus the logic is: use the most economical earth rod that soil conditions will permit the installer to drive.
Why do we need earthing?
Earthing is used to protect you from any kind of electric shock. It does this by providing a path, essentially a protective conductor for a fault current to flow to earth. It also causes the protective device either a circuit-breaker or fuse to switch off the electric current to the circuit that has the fault.
What is equipment earthing?
Equipment Earthing- This type of earthing is usually done in houses to protect the household equipment.
Why is earthing required?
Earthing is required to maintain the line voltage constant.
What is the best earth electrode?
Generally for normal work galvanized iron plates are preferred due to its lower cost in comparison to copper plates of dimension 30cm × 30cm which is found to be the most effective earth electrodes as these electrodes are not affected by the soil moisture.
Why is earthing important?
Selection of earthing is very important for human safety, the safety of houses, and various electrical equipment.
What is the earth plate made of?
The earth plate used here is generally made up of copper of size 60 cm × 60 cm × 3.18 mm and this plate is embedded 3meter in the ground.
What is the potential of Earthing?
Earthing provides a surface around and under a substation that is at a uniform potential and is approximately equal to zero potential or absolute earth potential as possible.
What is system earthing?
System Earthing – In this type of earthing the conductor having current is connected to the ground. System earthing is used to protect from lightning and voltage stabilization.
