Workshop Practice for Electrical and Industrial Engineers.

1. Workshop Practice
Lab # 01
Demonstration of Electrical safety, hazards and Precautions

2. About Me
• Academics
• BE Electrical Engineering, Hamdard University IslamabadCampus
• Enrolled in MS Electrical Engineering, NUSTCollage of E&ME
• Area of Interest
• Power Engineering Systems
• Power Electronics
• Automation

3. About Me
• Experience
• Electrical Engineer, Massive Energy Dynamics Faisalabad.
• Project Engineer, Falcon Dynamic Engineering Faisalabad.
• Contact me
Email: tr.persota@gmail.com
Cell # +92-322-676-0480

4. Class Introduction

5. Aims and objectives
In this lab students will learn about:
How electric current effects the body
Hazards and risks involved from electricity?
Legal duties and obligations around electricity
Basic electrical safety and precautions

6. How electric current affects the body
• Electric current affects the body when
it flows through.
• The basic unit of current is amp.
• This is the current which flows
through a resistance of 1 ohm when a
voltage of 1 volt is applied across it.
• However current as low as
thousandths of amps can have an
adverse effect on the body.
• The table gives the illustration of the
types of effects various levels of
current can have on the body.

7. Shock physiological effects

8. Who is most at risk from
electricity?
• Harm can be caused to any person when they are
exposed to ‘live parts’ that are either touched directly or
indirectly by means of some conducting object or
material.
• Voltages over 50 volts AC or 120 volts DC are considered
hazardous.
• Shocks from faulty equipment can cause severe and
permanent injury and can also lead to indirect injuries,
due to falls from ladders, scaffolds, or other work
platforms.

9. Who is most at risk from
electricity?
• Faulty electrical appliances can also lead to fires. As well
as causing injuries and loss of life, fires cause damage to
plant, equipment and property.
• Those most at risk include maintenance staff, those
working with electrical parts, equipment and machinery
and people working in harsh environment such as
construction sites.

10. Legal duties and obligations
around electricity
The moral duties on employers are to protect employees
and members of the public.
Have the electrical systems constructed in a way that
prevents danger.
Maintain their electrical systems as necessary to prevent
danger.
Have work on, use of, or closure of, electrical systems
carried out in a way that prevents danger.

11. Legal duties and obligations
around electricity
• Electrical equipment used in hazardous environments
(e.g., extremes of weather, temperature, corrosive
conditions) must be constructed or protected to prevent
it becoming dangerous
• Only those with adequate knowledge or experience, or
who are under adequate supervision should work with, or
on, electrical equipment that could cause danger or
injury.

12. Basic electrical safety
Below are some minimum steps you should take to ensure electrical safety.
Mains supplies
 Maintain all electrical installations in good working order
 Provide enough socket-outlets for equipment in use
 Avoid overloading socket-outlets – using adaptors can cause fires
 Provide an accessible and clearly identified switch ('Emergency Off' or
'EMO' button) near fixed machinery to cut off power in an emergency
 For portable equipment, connect to nearby socket-outlets so that it can
be easily disconnected in an emergency.

13. Use the right equipment
Choose electrical equipment that is suitable for its working
environment
Ensure that equipment is safe when supplied and maintain it in
a safe condition
Electrical equipment used in flammable/explosive
atmospheres should be designed not to produce sparks. Seek
specialist advice when choosing this type of equipment.
Protect light bulbs and other easily damaged equipment –
there is a risk of electric shock if they are broken.

14. Maintenance and repairs
Ensure equipment is fitted with the correctly rated fuse.
Ensure cable ends always have their outer sheaths firmly clamped to
stop wires working loose from plugs or inside equipment
Replace damaged sections of cable completely – never repair cuts with
insulating tape.
Use proper connectors to join lengths of cable – don't use connector
blocks covered in
insulating tape or 'splice' wires by twisting them together
Some equipment is double insulated.These are often marked with a
‘double-square’ symbol.
The supply leads have only two wires – live (brown) and neutral (blue).
Make sure all wires are connected securely if the 13A plug is not a
molded-on type.

15. Maintain your electrical
equipment and installations
Factors to consider during installation include:
 Type of equipment
 Where equipment is used
 Is equipment portable or transportable?
 Is it used in a harsh environment?

16. Work safety
Make sure that people working with electricity are
competent to do the job. Even simple tasks
such as wiring a plug can lead to danger ensure that people
know what they are doing before they start.

17. Work safety
Make sure that:
 Suspect or faulty equipment is taken out of use immediately
 Suspect or faulty equipment is labelled ‘DO NOT USE’
 Suspect or faulty equipment is kept secure until examined by a competent person
 Where possible, tools and power socket-outlets are switched off before plugging
in or unplugging
 Equipment is switched off and/or unplugged before cleaning or making
adjustments
 Where possible, all electrical appliances are switched off at the mains at the end
of the working day.

18. Electric Shock
o When human body accidently comes in contact with an electric
conductor connected to the supply, the electric current passes
through the body.
o This may cause the heart to stop beat, burns due to current arcing or
partial blockage of blood flow through vessels.
o Electricity should be treated with respect-it cannot be seen or heard,
but it can kill.
o A great deal of damage to property and caused, usually through fire
or explosions as a result of faulty wiring or faulty equipment.

19. Major Hazards
Electric shock
 The body responds in a number of ways to electric current flowing
through it.
 The chance of electric shock is increased in wet or damp conditions.
 Hot environment where sweat or humidity reduce the insulation
protection.
Electric burn
 This is due to heating effect caused by electric current passing
through body tissue.

20. Major Hazards
Fire
 Overheating of cables and electrical equipment due to overloading
 Leakage currents due to poor and inadequate insulation
 Overheating of flammable materials places too close to electrical equipment
 Ignition of flammable materials by sparking of electrical equipment
Arcing
 Generate ultra-violate radiation causing a particular type of burn.
 Molten metal resulting from arcing can penetrate.
 Arc eye in metal arc welding
Explosion
 These include the explosion of electrical equipment e.g., switchgear or motors or
where electricity causes the ignition of flammable vapors, gases or liquids.

21. Safety colors Signs and
Applications

22. Safety colors Signs and
Applications

23. General Precautions
Always use correct color codes when wiring
All electrical connections must be secure
Let fuses of correct rating be fitted always
Any external metallic part must be correctly earthed
Never run power tools from lamp sockets
Equipment should always be disconnected from the mains
before making adjustments
Connection between the plug and equipment should always
be made keeping in view the current rating of the equipment