International Islamic University,
Islamabad
Power Distribution and Utilization
EXPERIMENT # 1:
Safety and Precaution in Power System Laboratory
Name of Student: …………………………………..
Roll No.: ……………………………………………
Date of Experiment: ………………………………..
EXPERIMENT # 1:
Safety and Precaution in Power System Laboratory
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Lab Rules & Regulations
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All students of F17 are directed to follow the rules given below. If a student or group of students is
found violating these rules, he (or they) may be punished according to the department rules.
Arriving at time in lab.
Leaving at time.
Handle all equipment with care.
All students are liable for any damage to equipment due to their negligence.
All equipment, apparatus & tools must be returned to their original place after use.
Experiment must be completed within the given time.
Do not throw connecting wires on the floor; return them to the lab staff.
Before leaving the lab, turn off the power to all instruments and the main power switch of the lab
bench.
Students are strictly prohibited from taking out any items from the lab without the permission from
the laboratory staff.
Food, Drinks & Smoking is not allowed in the labs.
Students are not allowed to sit idle in the lab & group discussion is strictly prohibited.
Misuse and playing games on the lab computers or laptops are strictly prohibited.
Note: Excuse will not be entertained if anyone has clashes please removed your clashes of classes.
Viva of lab can be conducted at any time during lab.
Attendances of late comer will not be counted, and students of bellow 90% attendant will be
prevented.
Students keeping keen interest in lab and work hard will be awarded with bonus marks.
This lab is foundation for the upcoming batches.
This Laboratory courses related material will be handed over time to time as per need.
Rubrics sheet will be attached with manual of each lab. Marks of individual labs will be given as
per rubrics sheet.
Distribution of marks is as given bellow:
Marks of 14 labs = 50
Marks of Assignment/Report/Project =20
Marks of Final Term Examination = 30
2
Safety and Precautions
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Don't work alone - in the event of an emergency another person's presence may be essential.
Finally, never assume anything without checking it out for yourself! Don't take shortcuts!
Understand the procedure completely before starting the work.
Know the location and how to operate shut-off switches and/or circuit breaker panels. Use these
devices to shut off equipment in the event of a fire or electrocution.
5. Never energize any circuit unless you are sure that no one is working on the circuit. Give electric
supply to the wiring system only after thorough verification
6. Always keep one hand in your pocket or stick it with your body firmly is you are working with a
single hand when anywhere around a powered line-connected or high voltage system. Do not keep
your hand on somewhere on trainer.
7. Have a fire extinguisher rated for electrical fires readily accessible in a location that won't get
blocked should something burst into flames.
8. Strictly avoid contact with energized no insulated electrical circuits.
9. Treat all electrical devices as if they are alive or energized.
10. Take utmost care while handling lamps, lamp holders, switches etc, because these materials are
brittle.
11. Disconnect the power sources before servicing or repairing electrical equipment.
12. Use electrical tools and equipment with non-conducting handles when playing with electrical
circuits.
13. Strictly avoid help of material like pencil and rulers etc. while pointing any part of electrical
circuits. Use non-conductive tools whenever possible.
14. Working with wet hands is strictly prohibited
15. Any kind of drinking and eating is prohibited
16. If an individual comes in contact with a live electrical conductor, do not touch the equipment, cord
or person. Disconnect the power source from the circuit breaker
17. Drain the capacitors before working near them and keep it with short circuited terminals to prevent
electrical shock
18. Never touch any person’s equipment or electrical control devices unless needed
19. Avoid using broken socked and other faulty equipment.
20. If any fault observed inform the concern staff without any delay
21. Once the task is completed, before leaving make sure that the equipment is properly turned off
22. Avoid wearing loose clothing or ties near electrical equipment.
23. Stand on rubber pad when performing experiments.
24. Use good quality footwear/shoes in order to provide maximum resistance.
25. Keep safe yourself and your friends too.
3
Safety Devices
Importance of safety devices:
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The safety features are inbuilt with electric power distribution. The current is to flow
through the path it is expected to pass and should not take another path through which it is
not expected to pass. Conductors made of copper or aluminum are provided across the path
for carrying the current and insulators like PVC, paper or rubber are provided across the
path through which the current is not expected to flow.
Under abnormal condition there can be failure of insulations and current will flow through
the undesired path which can cause damage to equipment and more important the safety
of the user. Sometimes the user may inadvertently touch a live conductor and cause
electric shock. The circuit may also carry under short circuit condition much more than
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normal value of the current. The inbuilt safety features will isolate the faulty circuit from
the rest of the supply.
The very high currents caused by short circuit situation can cause lots of damage to
electrical installation. Protective devices are needed to break short-circuit and overload
currents.
Circuit breakers and fuses are protective devices that control the power going to a
particular route of wiring. In case of an overload or a short on that circuit, the breaker or
fuse trips and automatically shuts off power to that circuit. Fuses are the commonly
used protection devices to protect components like wires, transformers electronics
circuit modules against overload. The general idea of the fuse is that it "burns fuse
link" when current gets higher than its rating and thus stops the current flowing.
Types of Safety Devices
Basically, two types of protections are provided in the power supply system of
domestic consumers.
a. Protection from over current.
b. Protection from leakage current due to failure of insulation or inadvertent contact with
live conductors by the use.
On the bases of construction and functionality, the protection devices are distributed in
groups. The most popular types and families of these protection devices are given bellow:
1. Fuses
1.1 Rewireable Fuse
1.2 Cartridge Fuse
1.3 HRC Fuse
2. Circuit Breakers
2.1 Miniature Circuit Breaker (MCB)
2.2 Earth Leakage Circuit Breaker (ELCB)
3. Earthing
3.1 System Earthing
3.2 Equipment Earthing
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Exercise
Write down a comprehensive report on the each the given and discussed safety devices. (Clear picture and
one paragraph detail of each device)