Earthing and grounding systems are used to protect humans and equipment from electric shocks. Earthing works by providing an alternative path for fault currents to flow safely into the earth, rather than through a person. It connects exposed metal parts to the earth to drain away stray currents. Grounding provides an effective return path for main currents and protects power system equipment. While both terms refer to connecting to earth, earthing focuses on safety and protection, while grounding balances unbalanced loads and provides a return path. A complete earthing system includes an earth continuity conductor, earthing lead, and earth electrode buried underground. Proper earthing is important for safety and reliability of electrical installations.

1. Presented By :
Anurag Singh
+91-9821283422
S3 Energy Pvt. Ltd.
Project Operations

2. What is earthing and why it is done?
• Connecting the metallic (conductive) Parts of an Electric appliance or
installations to the earth (ground)so as to have discharge of electrical
energy.
Its Need: To ensure safety from electric shocks.

3. How it Works & Its Importance?
Earthing is used to protect us from an electric shock. It does this by
providing a path (a protective conductor) for a fault current to flow to
earth.
One of the most important reasons for grounding electrical currents is
that it protects your appliances, your home and everyone in it from
surges in electricity. ... If your electrical system is grounded, all of that
excess electricity will go into the earth — rather than frying everything
connected to your system.

4. How grounding is different from earthing?
• Earthing is done not for return path but only for protection of delicate
equipments. It is an alternate low resistance path for current.
• When we take out the neutral for a three phase unbalanced
connection and send it to ground, it is called grounding. Grounding is
done to balance unbalanced load.

5. Earthing…
• Earthing means connecting the dead part (it means the part which does not carries current
under normal condition) to the earth for example electrical equipment’s frames, enclosures,
supports etc.
• The purpose of earthing is to minimize risk of receiving an electric shock if touching metal
parts when a fault is present.
• Under fault conditions the metal parts of an electrical installation such as frames, enclosures,
supports, fencing etc. may attain high Current so that any person or stray animal touching
these parts can get Electric Shock .
• To avoid electrical shock metal parts of the electrical system are connected to the general
mass of earth by means of an earthing system comprising of earth conductors to conduct the
fault currents safely to the ground.
• 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.
• Green wire is used for this as a nomenclature.

6. Grounding…
• Grounding means connecting the live part (it means the part which carries current under normal
condition)
• Grounding is done for the protection of power system equipment and to provide an effective
return path from the machine to the power source. For example grounding of neutral point.
• Because of lightening, line surges or unintentional contact with other high voltage lines, high
voltages can develop in the electrical distribution system wires. Grounding provides a safe,
alternate path around the electrical system of your house thus minimizing damage from such
occurrences.
• Generally Black wire is used for this as a nomenclature.

7. Micro Difference between earthing & Grounding:
• There is no major difference between earthing and Grounding, both means “Connecting an electrical circuit
or device to the Earth”.
-This serves various purposes like to drain away unwanted currents. Even though there is a micro difference
between grounding & earthing.
Difference in Terminology:
• In USA term Grounding is used but in UK term Earthing is used.
Balancing the Load Vs Safety:
• Ground is a source for unwanted currents and also as a return path for main current some times. While earthing is done
not for return path but only for protection of delicate equipments. It is an alternate low resistance path for current.
• When we take out the neutral for a three phase unbalanced connection and send it to ground, it is called grounding.
Grounding is done to balance unbalanced load. While earthing is used between the equipment and earth pit so as to avoid
electrical shock and equipment damage.

8. Equipment Protection Vs Human Safety:
• Earthing is to protect the circuit elements whenever high voltage is passed by thunders or by any
other sources while Grounding is the common point in the circuit to maintain the voltage levels.
• Earthing is used for the safety of the human body in fault conditions while Grounding (As neutral
earth) is used for the protection of equipments.

9. Why are there 3 pins on a plug?
• This is connected to the earth pin. This is used when the appliance
has a metal casing to take any current away, in case if the live wire
comes in contact with the casing. A 3-pin plug consists of three
pins (hence the name). ... This type plug is commonly used for heavy
appliances such as the air-conditioners

10. Why the earth pin is longer?
• The earth pin on a plug is longer than the live and neutral pins. This
means the earth pin is the first to connect and the last to disconnect.
When inserting the plug, the earth connection is made before the
current carrying contacts of the plug become live.

11. Purpose of Earthing:
Safety for Human life/ Building/Equipments:
• To save human life from danger of electrical shock i.e. To provide an alternative path for the fault
current to flow so that it will not endanger the user.
• To protect buildings, machinery & appliances.
• To ensure that all exposed conductive parts do not reach a dangerous potential.
• To provide safe path to dissipate lightning and short circuit currents.
Over voltage protection:
• Lightning, line surges or unintentional contact with higher voltage lines can cause dangerously
high voltages to the electrical distribution system. Earthing provides an alternative path around
the electrical system to minimize damages in the System.

12. POINTS TO BE EARTHED
Earthing is not done anyhow. According to IE rules and IEE (Institute of Electrical Engineers)
regulations,
• Earth pin of 3-pin lighting plug sockets and 4-pin power plug should be efficiently and
permanently earthed.
• All metal casing or metallic coverings containing or protecting any electric supply line or
apparatus such as GI pipes and conduits enclosing VIR or PVC cables, iron clad switches, iron clad
distribution fuse boards etc should be earthed (connected to earth).
• The frame of every generator, stationary motors and metallic parts of all transformers used for
controlling energy should be earthed by two separate and yet distinct connections with the earth.
• In a dc 3-wire system, the middle conductors should be earthed at the generating station.
• Stay wires that are for overhead lines should be connected to earth by connecting at least one
strand to the earth wires.

13. Components of Earthing System
A complete electrical earthing system consists on the following basic components.
• Earth Continuity Conductor
• Earthing Lead
• Earth Electrode

14. Earth Continuity Conductor or Earth Wire
• That part of the earthing system which interconnects the overall metallic parts of electrical
installation e.g. conduit, ducts, boxes, metallic shells of the switches, distribution boards, fuses,
Regulating and controlling devices, metallic parts of electrical machines such as, motors,
generators, transformers and the metallic framework where electrical devices and components
are installed is known as earth wire or earth continuity conductor
• The resistance of the earth continuity conductor is very low. resistance of earth wire should be
less than 1Ω.
• Size of the Earth Continuity Conductor or Earth Wire depends on the cable size used in the wiring
circuit
• The cross sectional area of the Earth Continuity Conductor should not be less than the half of the
cross sectional area of the thickest wire used in the electrical wiring installation.
• Generally, the size of the bare copper wire used as earth continuity conductor is 6mm. But keep in
mind that, don’t use less than 2mm as earth wire.

15. Earthing Lead or Earthing Joint
• The conductor wire connected between earth wire and earth electrode is called “Earthing lead”.
& The point where earth continuity conductor and earth electrode meet is known as “connecting
point”.
• Earthing lead is the final part of the earthing system which is connected to the earth electrode
(which is underground) through earth connecting point.
• Copper wire can be used as earthing lead ,Copper strip is also used for high installation and it can
handle the high fault current because of wider area than the copper wire.

16. Size of the Earthing Lead
• The size or area of earthing lead
should not be less than the half of
the thickest wire used in the
installation.
• The largest size for earthing lead is
6mm and the minimum size should
not be less than 4mm. If the load
current is 200A from the supply
voltage, then it is recommended to
use copper strip instead of double
earthing lead. The earth lead
connection methods is shown in fig.

17. Earthing Electrode or Earth Plate
• A metallic electrode or plate which is buried in the
earth (underground) and it is the last part of the
electrical earthing system is called earth plate or
earth electrode.
• A metallic plate, pipe or rode can be used as an
earth electrode which has very low resistance and
carry the fault current safely towards ground
(earth).

18. Size of Earthing Electrode
• Both copper and iron can be used as earthing electrode.
• The size of earth electrode (In case of copper)
• 2×2 (two foot wide as well as in length) and 1/8 inch thickness.. i.e. 2’ x 2’ x 1/8”.
(600x600x300 mm)
• In case of Iron : 2’ x2’ x ¼” = 600x600x6 mm
• It is recommended to bury the earth electrode in the moisture earth. If it is not possible,
then put water in the GI (Galvanized Iron) pipe to make possible the moisture condition.
• In the earthing system, put the earth electrode in vertical position (underground) as
shown in the above fig. Also, put a 1 foot (about 30cm) layer of powdered charcoal and
lime mixture around the earth plate (earth electrode and earth plate as both are the
same thing).
• This action makes the possible increase in the size of the earth electrode which leads a
better continuity in the earth (earthing system) and also helps to maintain the moisture
condition around earth plate.

19. Earth Plate or Earth Electrode Size for Small installation
• In small installation, use metallic rod (diameter = 25mm (1inch) and length = 2m (6ft) instead of
earth plate for earthing system. The metallic pipe should be 2 meter below from the surface of
ground. To maintain the moister condition, put 25mm (1inch) coal and lime mixture around the
earth plate.
• For effectiveness and convenience, you may use the copper rods 12.5mm (0.5 inch) to 25mm (1
inch) diameter and 4m (12ft) length. We will discuss the installation method of rod earthing latter.

20. Methods of Earthing | Types of Earthing
Plate Earthing:
• In plate earthing system, a plate made up of either copper with dimensions 60cm x 60cm x
3.18mm or galvanized iron (GI) of dimensions 60cm x 60cm x 6.35 mm (2ft x 2ft x ¼ in) is buried
vertical in the earth (earth pit) which should not be less than 3m (10ft) from the ground level.
Pipe Earthing:
• A galvanized steel and a perforated pipe of approved length and diameter is placed vertically in a
wet soil in this kind of system of earthing. It is the most common system of earthing.

21. Rod Earthing
• It is the same method as pipe earthing. A copper rod of 12.5mm (1/2 inch) diameter or 16mm
(0.6in) diameter of galvanized steel or hollow section 25mm (1inch) of GI pipe of length above
2.5m (8.2 ft) are buried in earth
Earthing through the Waterman
• In this method of earthing, the waterman (Galvanized GI) pipes are used for earthing purpose.
• If stranded conductor is used as earth wire, then clean the end of the strands of the wire and
make sure it is in the straight and parallel position which is possible then to connect tightly to the
waterman pipe.
Strip or Wire Earthing:
• In this method of earthing, strip electrodes of cross-section not less than 25mm x 1.6mm
(1in x 0.06in) is buried in a horizontal trenches of a minimum depth of 0.5m.

22. General method of Earthing / Proper Grounding Installation (Step by Step)
• The usual method of earthing of electric equipments, devices and appliances are as follow:
• First of all, dig a 5x5ft (1.5×1.5m) pit about 20-30ft (6-9 meters) in the ground. (Note that, depth and
width depends on the nature and structure of the ground)
• Bury an appropriate (usually 2’ x 2’ x 1/8” (600x600x300 mm) copper plate in that pit in vertical
position.
• Tight earth lead through nut bolts from two different places on earth plate.
• Use two earth leads with each earth plate (in case of two earth plates) and tight them.
• To protect the joints from corrosion, put grease around it.
• Collect all the wires in a metallic pipe from the earth electrode(s). Make sure the pipe is 1ft (30cm)
above the surface of the ground.
• To maintain the moisture condition around the earth plate, put a 1ft (30cm) layer of powdered
charcoal (powdered wood coal) and lime mixture around the earth plate of around the earth plate.
• Use thimble and nut bolts to connect tightly wires to the bed plates of machines. Each machine should
be earthed from two different places. The minimum distance between two earth electrodes should be
10 ft (3m).
• Earth continuity conductor which is connected to the body and metallic parts of all installation should
be tightly connected to earth lead.
• At last (but not least), test the overall earthing system through earth tester. If everything is going about
the planning, then fill the pit with soil. The maximum allowable resistance for earthing is 1Ω. If it is
more than 1 ohm, then increase the size (not length) of earth lead and earth continuity conductors.
Keep the external ends of the pipes open and put the water time to time to maintain the moisture
condition around the earth electrode which is important for the better earthing system.

23. ADVANTAGES OF EARTHING
The following are the few advantages:
• Reduced operation & Maintenance cost
• Improved lightning protection.
• Simplification of ground fault location.
• Improved system and equipment fault protection.
• Improved service reliability
• Greater safety for personnel & equipment
• Prompt and consistent operation of protective devices during earth
fault.

24. The disadvantages of earthing
The two important disadvantages are:
• Cost: the provision of a complete system of protective conductors, earth electrodes, etc. is very
expensive.
• Possible safety hazard: It has been argued that complete isolation from earth will prevent shock
due to indirect contact because there is no path for the shock current to return to the circuit if
the supply earth connection is not made
Fig 5.3Danger in an unearthed system
a) apparent safety: no obvious path for shock current
b) actual danger: shock current via stray resistance and
capacitance

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