This document discusses earthing and electrical safety. It describes earthing as connecting electrical equipment to the earth to protect humans from electric shock. It then discusses different earthing methods like strip, plate, pipe and rod earthing. It explains the purpose of earthing is to protect lives and equipment from lightning and overvoltage. It also covers causes of electrical shock and types of protective devices like fuses, ELCBs and MCBs. In summary, the document outlines earthing techniques, its importance for safety, causes of shocks and protective equipment.

1. SAFFRONY INSTITUTE OF TECHNOLOGY
S.P.B PATEL ENGINEERING COLLEGE
MECHANICAL DEPARTMENT CLASS-ME2
PATEL SUJAY(130390119086)
PATEL TRUPAL (130390119087)
PATEL UMANG(1303901190)
Guided by :-
Mr.Malay Bhatt

2.  Earthing
• All the people living or working in residential, commercial and industrial
installations, particularly the operators and personnel who are in close
operation and contact with electrical systems and machineries, should
essentially be protected against possible electrification.

3. What Is Earthing
• The process of connecting metallic bodies of all the electrical
apparatus and equipment to huge mass of earth by a wire having negligible
resistance is called Earthing.

4. Purpose of earthing
• To save human life from danger or shock or death by blowing fuse
of any apparatus which becomes leaky
• To protect all machines fed from over head lines from lighting
• To protect large building from atmospheric lightning
• To maintain the line voltage constant

5. Various method of earthing
1.Strip earthing: this system of earthing employs the use of 5 SWG
copper wire or srip of cross –section not less than 25mm*1.6mm. The
strips or wires are barried in horizontal trenches . The type of earthing
is used where the earth bed has rocky soil
2.earthing through water mains: in this type of earthing , a stranded
copper lead is used is rounded on the pipe with the help of steel
binding wire and properly designed earthing clip . The copper lead is
soldared to make it solid . Before making connection to the water main
,it should be ensured that G.I. pipe is used throughout

6. 3.Rod earthing: it is the chepest method of earthing and is
employed in sandy areas . In this method , a copper rod is
hammered directly into earth and no excavation work is
required . The earthing lead is joined to this rod with the help
of nuts and bolts

7. 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.

9. 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.

11. 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

12. CAUSES OF ELECTRICAL SHOCK WHILE
WORKING ON LINE
• If a person comes in contact with a bare conductor through which
current is flowing he will get electical shock
• If thare be leakage of current through insulation of an electrical
circuit at a particular point and person comes and contact with
circuit person get high voltage shock greter than the leakage
current
• If earthing is not effective and continuity of earth wire is not
maintaned metal pipe of wiring system such wiring system any
person coming in contact with he will get electrical shock

13. • If a single pole switch placed in the neutral line the
live line will be passing lamp holder to fan and this case
the any person comes to contact wit bulb ya fan
terminal he get shock
• If a fuse wire is inserted in the neutral line and due to
some reason the fuse wire melts while connection of
live line the person comes to contact with fuse he get
electricalshock

14. TYPES OF ELECTRICAL PROTECTIVE DEVICES

15. Type of fuse

16. ELCB (Earth Leakage Circuit Breaker)

17. MCB

18. Characteristics
Phase (line), Neutral and Earth wire connected
through ELCB.
ELCB is working based on Earth leakage current.
Operating Time of ELCB:
The safest limit of Current which Human Body can withstand is 30ma
sec.
Suppose Human Body Resistance is 500Ω and Voltage to ground is 230
Volt.
The Body current will be 500/230=460mA.
Hence ELCB must be operated in 30maSec/460mA = 0.65msec

19. THANK YOU