Earthing

1. Elements of Electrical Engineering
“Topic: Earthing”
Guided By:
Prof. Rahish Silavat
Branch : Mechanical Engineering Div: L-3

2. Group Member
• Harshil Zaveri(130120119251)

3. EARTHING

4. WHAT IS EARTHING?
 The term Earthing means the connection of the
neutral point of the supply system or non current
carrying parts of electrical apparatus, such as
metallic frame work, metallic covering of cables,
earth terminal of socket outlet, stay wire etc. to the
general mass of earth in such a manner that at all
times immediate discharge of electrical energy
takes place without danger.

5. VARIOUS CIRCUIT DIAGRAM OF EXPLAINING EARTHING

6. PURPOSE OF EARTHING
• To save human life from danger of electrical shock or death by
blowing a fuse 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 under fault
conditions ie. To ensure that all exposed conductive parts do not
reach a dangerous potential.
• To provide safe path to dissipate lightning and short circuit
currents.
• To provide stable platform for operation of sensitive electronic
equipments i.e. To maintain the voltage at any part of an
electrical system at a known value so as to prevent over current
or excessive voltage on the appliances or equipment .
• To provide protection against static electricity from friction

7. GOOD EARTHING MEANS
Good Earthing must have low impedance
enough to ensure that sufficient current can
flow through the safety device so that it
disconnects the supply ( <0.4 sec ). Fault
current is much more than the full load
current of the circuit which melts the fuse.
Hence, the appliance is disconnected
automatically from the supply mains.

8. QUALITIES OF GOOD EARTHING
 Must be of low electrical resistance
• Must be of good corrosion resistance
• Must be able to dissipate high fault current repeatedly

9. VARIOUS METHOD OF EARTHNG
1. Strip Earthing
2. Earthing through water mains
3. Rod Earthing
4. Pipe Earthing
5. Plate Earthing

10. (1) STRIP EARTHING
 This system of Earthing employees the use of
copper wire or strip of cross section not less than
25 mm X 1.6 mm.
 The strips or wires are burried in horizontal
trenches.
 This type of Earthing is used where the earth bed
has a rocky soil and excavation work is difficult.

11. (2) EARTHING THROUGH WATER MAINS
 In this type of Earthing, standard copper lead is
used which is rounded on the pipe with the help of
a steel binding wire and properly designed
Earthing clip.
 The copper lead is soldered to make it solid.
 Before making connection to the water main, it
should be ensured that G.I pipe is used through
out.

12. (3)ROD EARTHING
 It is the cheapest method of Earthing and is
employed in sandy areas.
 In this method, a copper rod is hammered directly
into the earth and no excavation work is required.
 The Earthing lead is joined to this rod with the help
of nuts and bolts

13. (4) PIPE EARTHING

14. PIPE EARTHING
 Pipe earthing is best form of earthing and it is cheap also in this system
of earthing a GI pipe of 38 mm dia and 2meters length is embedded
vertically in ground to work as earth electrod but the depth depend upon
the soil conditions, there is no hard and fast rule for this.
 But the wire is embedded upto the wet soil.
 The earth wire are fastened to the top section of the pipe with nut and
bolts.
 The pit area arround the GI pipe filled with salt and coal mixture for
improving the soil conditions and efficiency of the earthing system.
 It can take heavy leakage current for the same electrode size in
comparison to plate earthing.
 The earth wire connection with GI pipes being above the ground level
can be checked for carrying out continuity test as and when desired,
while in plate earthing it is difficult.
 In summmer season to have an effective earthing three or four bucket of
water is put through the funnel for better continuity of earthing.

15. PLATE EARTHING

16. PLATE EARTHING
 In this type of earthing plate either of copper or of
G.I. is buried into the ground at a depth of not less
than 3 meter from the ground level.
 The earth plate is embedded in alternative layer of
coke and salts for a minimum thickness of about
15cm.
 The earth wire(copper wire for copper plate
earthing and G.I. wire for G.I. plate earthing) is
securely bolted to an earth plate with the help of
bolt nut and washer made of copper, in case of
copper plate earthing and of G.I. in case of G.I.
plate earthing.

17. APPLICATIONS
• Telecommunication
• Transmission
• Substations & Power Generations
• Transformer Neutral earthing
• Lightning Arrestor Earthing
• Equipment Body Earthing
• Water Treatment Plants
• Heavy Industries
• College, Hospitals, Banks
• Residential Building

18. Thank You