Electrical safety PPT

1. ELECTRICAL SAFETY PPT
Sudarshan Chemical Industries Limited- Roha
DEEPAKSINGH

2. WHAT IS ELECTRICITY
Electricity is an invisible phenomenon created by
the movement of electrons in a conductor.
Basic Electrical Theory
• Voltage [driving force] causes current [e - ] to flow
AC / DC - from safety perspective - negligible
difference .
Single Phase / Three Phase. 3f get a professional
• Circuit / loop is necessary for current to flow
a start point - a route - an end point

3. ELECTRICAL HAZARDOUS
What are the hazards of electricity and electrical
equipment?
•Shock
•Electrical arcs and blasts
•Rescues
•Ground faults
•Extension cords
•Broken or faulty equipment

4. ELECTRICAL MATERIAL
Conductor :- A material that contains many free electrons and is capable
of carrying an electric current is called a conductor.Metals and (generally)
water are conductors. Gold, silver, aluminum and copper are all good
conductors.
Insulator :- Materials that contain relatively few free
electrons are called insulators. Non-metallic materials
such as wood, rubber, glass and mica are insulators.
Fair conductorsinclude the human body, earth,
and concrete.

5. TYPES OF ELECTRICITY
There are two forms of electricity…
● Static electricity
Electricity that gathers in one place
● Current electricity
Electricity that moves from one place to another

6. HOW DOES ELECTRICITY WORK
How does electricity work?
Electricity is the flow of electrons around a circuit
● Electrons carry electrical energy from one place to another, creating
current electricity, or an electric current
● For an electric current to happen, there must be a circuit
● A closed path, or loop around which an electric current flows

7. RULES OF ELECTRICITY
Electricity
Rules
● Electricity travels in a
completed circuit path .
● Electricity always travels in the
path of low resistance.
● Electricity tries to travel in
shortest path .
● Electricity always tries to travel
to ground .

8. ELECTRICITY AND HUMAN
A person usually offers a lesser resistance path for
the electricity .
The personforms a completedcircuit when
touching the Ground and Electricity.
The personforms a shortestpath when touching
the Electricity .

9. WHERE TO START ?
Safety
Starts
Here………………
Think Safe ……
Work Safe ……
Be Safe

10. WHY ELECTRICAL SAFETY IS IMPORTANT
Electrical hazards can cause burns, shocksand electrocution .
Electrocution: Among most frequent causes of occupational
injury or death at Workplaces.
Electricity travels in closed circuits, normally through a
conductor.
Your body can be a conductorwhich may means an electrical shock .

11. WHY SAFETY IS REQUIRED
UNSAFE ACT SAFE ACT

12. EFFECTS OF ELECTRICITY ON HUMAN BODY

13. EFFECTS OF ELECTRICITY ON THE
HUMAN BODY
ELECTRICAL SHOCK
● Current passes through the body.
● Varied type of effects are faced by body from
tingling sensation to electrocution.
● Severity of the shock depends on:
– Path of current through the body
– Amount of current flowing through the body .
– Length of time the body is in the circuit
● Low voltage does not mean low hazard .

14. EFFECTS OF ELECTRICITY ON THE
HUMAN BODY
● 5 mA – 10 mA Throw off, painful sensation.
● 10 mA – 15 mA Muscular contraction, can’t let go
● 20 mA – 30 mA Impaired breathing
50 mA and above Ventricular fibrillation and death
Electrical Shock Levels

15. TYPES OF INJURIES CAUSED BY
ELECTRIC SHOCK
• Following are major types of electrical injuries :-
– Direct injuries
• Electrocution
• Electrical Shock
• Burns
• Arc Blasts
– Indirect injuries
• Falls

16. ELECTRICAL SHOCK

17. ELECTRICHAZARD CAUSES
ELECTRICAL HAZARDS - CAUSES
1. Improper Grounding
2. Exposed Electrical Parts
3. Inadequate Wiring
4. Damaged Insulation
5. Overloaded Circuits
6. Damaged Tools &
Equipment
7. Wet Conditions
8. Overhead Power Lines

18. The complete Electrical circuit
A complete Circuit or loop is necessary for current to flow

19. DIFFRENCEBETWEEN ELECTRICAL
EARTHINGSYSTEMANDWITHOUTEARTHINGSYSTEM
EQUIPMENT WITHOUT EARTHING EQUIPMENT WITH EARTHING

21. Electrical Accidents Nature and Protect
Nature of Electrical Accidents:-
Electrical incidents are caused by many different events; however we
can identify three common root causes for just about any electrical incident:
• Working on unsafe equipmentand installations;
• Unsafe Environment(i.e. wet environment/ presence of flammable
vapors); and
• Unsafe work performance
Ways to Protect the Workers :-
There exists a number of waysto protect workers from the threat of electrical hazards.
Here are a few of the protective methods:
• De-energize the circuit
• Work Practices
• Insulation
• Guarding
• Barricades
• Ground Fault Circuit Interrupters (GFCI)
• Grounding (secondary protection)

22. Electrical Overload Hazards
• If too many devices are plugged into a circuit, the current will heat the wires
to a very high temperature, which may cause a fire .
• If the wire insulation melts, arcing may occur and cause a fire in the area where
the overload exists, even inside a wall .

23. Electrical Arc Flash & Arc Blast
Arc Flash – Electrical short circuit that occurs when air flashes from an exposed
live conductor, to either another conductoror to ground.
Arc Blast – Pressure wave caused by the arc flash
• Concentrated energy explodes outward
• High intensity flash
• Temperatures can reach 35,000 (skin ignites 480)
• Pressure wave can reach 200lbs/sq. inch
• Vaporizes conductorsand copper with exploding particles.
Causes Of Electrical Arc Flash:-
•Improper training
•Improper work procedures
•Dropped tools
•Accidentalcontact with electrical systems
•Installation failure
•Improper Design/Repair
•Voltage testing with inappropriate equipment

24. EMPLOYEE RESPONSBILITY
• Follow safe work practices.
• Make sure lines are de-energized before your work on them.
• Wear required PPE.
• Alert your co-workers to any unsafe work practices.
• Report all problems to your supervisor.
• Know what to do in the event of an emergency .
• Use electrical tools and equipment that are protected by a GFI.
• Review your assignmentswith your supervisors.
• Utilize correct PPE.
• Report all problems to your supervisors.
• If at all in doubt, ask questions .

25. ELECTRICALQUALIFIEDVSUNQUALIFIEDPERSONS
QUALIFIED PERSONS UNQUALIFIED PERSONS
• The standard defines a qualifiedperson as one
familiarwith the construction and
operationof the equipment and the hazards
involvedthose who are permitted to
work on or near exposed energized parts .
• Whether an employeeis considered to be a "qualified
person" will depend on variouscircumstances in the
workplace. It is possible and, in fact, likely for an
individual tobe considered "qualified"with regard to
certain equipmentin the workplace, but
"unqualified" asto other equipment..
• The training requirementscontainedin this
section apply to employees who face a risk of
electric shock that is not reduced to a safe level by
the electrical installation requirements.
• Employees shall be trainedin and familiarwith
the safety-related work practices required to their
respective job assignments.

26. PPE FOR SAFETY
Employees working in areas where
there are potential electrical hazards
shall be provided with, and shall use,
electrical protective equipment that is
appropriate for the specific parts of the
body to be protected and for the work
to be performed .

27. HOW TO PROTECT FROM ELECTRICITY
Protect yourself from electricity
• Follow specialized procedures in wet work areas
• Use lockout/tag out
• Conduct inspections
• Follow assured grounding programs
• Use GFCIs
• Guard energized parts

28. WET AREA
Wet Areas
•If you touch a live wire or other electrical component while standing in
even a small puddle of water, you will get shocked
•Avoid working in wet conditions whenever possible
•Use approved electrical equipment for wet conditions and
do not stand in wet areas when operating electrical equipment

29. HOW DOES ELECTRICITY WORK
Voltage :-
•A kind of electrical force that makes electricity move through a wire
•Measured in volts
•The bigger the voltage,the more the current will tend to flow
Current :-
•A steady flow of electrons, measured in amperes (or amps) .

30. LOCKOUT / TAGOUT
Lockout/ Tagout :-
• Proper lockout/tag out procedures protect
workers from the unexpected start-up of electrical
equipment.
• These procedures make sure that electrical
equipment is de-energized before it is repaired and
protect workers against electric shock.

31. ELECTRICAL INSPECTION
• Visually inspect
• All electrical equipment before use .
• Remove any equipment with frayed cords,
missing ground prongs, cracked tool casings, etc.
, from service .
• Check Visual Inspection before Charging any feeder
& equipment ( Like overheating and damage inside) .

32. ASSURED GROUNDING PROGRAM
• Assured Grounding Program
• This includes a written program, daily visual inspections,
and a method to detect a faulty grounding wire in an extension
cord or hand tool.
• Grounding gives a stray current somewhere to go and keeps workers
from becoming part of the circuit.

33. ELECTRICAL GROUNDING
•Locating or enclosing electric equipment to make sure
workers do not accidentally come into contact with
its live parts .
•Requires equipment with exposed parts operating at 50
volts or more to be placed where it is accessible only to
authorized workers qualified to work with it .

34. SAFETY TO BE FOLLOW AT SITE
Safety
First
• Sign boards/ Warning Indications should be placed wherever
necessary.
• Should use Proper PPE while attending any installation/
maintenance/troubleshooting .
Safety
First
Safety
First
• PPE (Personal Protection Equipment) includes fall protection, arc flash protection,
fire rated clothing, gloves, boots, and protective eyewear, among other items .
• All personnel working on or near PV systems should be trained to recognize
hazards and choose the appropriate PPE to eliminate or reduce those hazards.
• Always keep the record of assigned tasks, incidents outcome and the person
in charge of the site and people who are working at site.
• Always have Layout/Route map of the Chemical Plant .

35. Extinguisher Classification
Letter classification given an extinguisher to designate the class or
classes of fire on which it will be effective.
• Class A – ordinary combustibles (wood, cloth, paper)
• Class B – flammable liquids, gases, greases .
• Class C – energized electrical equipment
• Class D – combustible metals.
• Class K – Kitchen Oil and Fats .

36. Electrical Safety Helmets
Head protective helmets into two different types and three different classes.
Type 1 :- Helmets incorporatea full brim (brim fully encircles the dome of the hat) .
Type 2 :- Helmets have no encircling brim, but may include a short bill on the front .
Class A :-
Helmets reduce the force of impact of fallingobjects and also reduce
the danger of contact with exposed low-voltageelectrical conductors. Helmet
shells are proof-tested at 2,200 voltsof electrical charge.
Class B :-
Helmets reduce the force of impact of fallingobjects and also reduce
the danger of contact with exposed high-voltageelectrical conductors. Helmet
shells are proof-tested at 20,000 volts.
Class C :-
Helmets reduce the force of impact of fallingobjects, but offer no
electrical protection.

37. Electrical Hand Gloves
Insulatinggloves provide an excellent means of protecting the workers from accidentalelectricalcontact. To be effective
the insulatinggloves must have high insulativequalities,while also being comfortable, durable and flexible.

38. EXPLOSION
• An explosion is defined as a sudden reaction involving
rapid physical or chemical decay accompanied by an
increase in temperature or pressure or both.
• The most common types of reaction are between
flammable gases, vapors, or dust with oxygen contained in
the surrounding air.
• 3 basic requirements must be met for an explosion to take
place in atmospheric air.
FLAMMABLE SUBSTANCES:
• Flammable substances can be divided into three subgroups:
• Flammable gas. Example: Hydrogen, etc.
• Flammable liquids/vapors. Example: Hydrocarbons such as ether,
acetone, lighter fluids, etc.
• Flammable solids: Dust, fibers, and flyings
IGNITION SOURCES (Industrial electrical equipment):
• Hot surfaces
• Electrical sparks
• Friction and impact sparks
OXIDISER:
The oxidizer referred to in all common hazardous location standards
and explosion-proof equipment is air at normal atmospheric
conditions.
EXPLOSION
IGNITION SOURCE
OXIDIZER
FLAMMABLE
SUBSTANCE

39. HOW IS EXPLOSION CONTROLLED?
• If one of the three elements of the ignition triangle is missing, ignition will not occur.
• Since flammable substance and oxidizers cannot be frequently eliminated with certainty, inhibiting ignition of a potentially
explosive atmosphere can eliminate danger at the source.
• The objective of selecting an electrical apparatus and the means of installation is to reduce the hazard of the electrical apparatus
to an acceptable level. An acceptable level might be defined as selecting protective measures and installation means to ensure
that the probability of an explosion is not significantly greater due to the presence of electrical apparatus than it would have
been had there been no electrical apparatuspresent.
• The most certain method of preventing an explosion is to locate electrical equipment outside of hazardous (classified) areas
whenever possible. In situations where this is not practical, installation techniques and enclosures are available which meet the
requirements for locating electrical equipment in such areas.
• Regulation on hazardous location by means of the Class/Division system have now been formulated by the NEC, CEC, OSHA, and
the National Fire Protection Association (NFPA). Adherence to these regulations is required by manufacturers and operators of
equipment.

40. EXPLOSIVE GAS AREA CLASSIFICATIONS
• Typical gas hazards are from hydrocarbon compounds, but hydrogen and ammonia are common industrial gases that are flammable.
Classification Description
Class I, Division 1
classified locations
An area where ignitable concentrations of flammable gases, vapors or liquids can exist all of the time or some of the
time under normal operating conditions. A Class I, Division 1 area encompasses the combination of Zone 0 and Zone 1
areas.
Zone 0 classified location: An area where ignitable concentrations of flammable gases, vapors or liquids are present
continuously or for long periods of time under normal operating conditions. An example of this would be the vapor
space above the liquid in the top of a tank or drum (As a guide for Zone 0, this can be defined as over 1000 hours/year
or >10% of the time)
Zone 1 classified location: An area where ignitable concentrations of flammable gases, vapors or liquids are likely to
exist under normal operating conditions (As a guide for Zone 1, this can be defined as 10–1000 hours/year or 0.1–10%
of the time)
Class I, Division 2
or Zone 2
classified locations
An area where ignitable concentrations of flammable gases, vapors or liquids are not likely to exist under normal
operating conditions. In this area the gas, vapor or liquids would only be present under abnormal conditions (As a
general guide for Zone 2, unwanted substances should only be present under 10 hours/year or 0–0.1% of the time)
Unclassified
locations
Also known as non-hazardous or ordinary locations, these locations are determined to be neither Class I, Division 1 or
Division 2; Zone 0, Zone 1 or Zone 2; or any combination thereof.

41. EXPLOSIVE DUST AREA CLASSIFICATIONS
• Flammable dust when suspended in air can explode.
• According to NEC:
Classification Description
Class II, Division 1
classified locations
An area where ignitable concentrations of combustible dust can exist all of the time or some of the time under
normal operating conditions
Class II, Division 2
classified locations
An area where ignitable concentrations of combustible dust are not likely to exist under normal operating
conditions
Class III, Division 1
classified locations
An area where easily ignitable fibers or materials producing combustible flying's are handled, manufactured or
used.
Class III, Division 2
classified locations
An area where easily ignitable fibers are stored or handled.

42. EXPLOSIVE DUST AREA CLASSIFICATIONS
Classification Description
Zone 20 classified
locations
An area where ignitable concentrations of combustible dust or ignitable fibers/ flyings are present continuously or for
long periods of time under normal operating conditions.
Zone 21 classified
location
An area where ignitable concentrations of combustible dust or ignitable fibers/ flyings are likely to exist under normal
operating conditions.
Zone 22 classified
locations
An area where ignitable concentrations of combustible dust or ignitable fibers/ flyings are not likely to exist under
normal operating conditions.
Unclassified locations Also known as non-hazardous or ordinary locations, these locations are determined to be neither Class II, Division 1
or Division 2; Class III, Division 1 or Division 2; Zone 20, Zone 21 or Zone 22; or any combination thereof.

43. GAS AND DUST GROUPS
NEC Division System Gas & Dust Groups
Area Group Representative Materials
Class I, Division 1 & 2
A Acetylene
B Hydrogen
C Ethylene
D Propane
Class II, Division 1 & 2
E (Division 1 only)
Metal dusts, such as magnesium (Division 1
only)
F
Carbonaceous dusts, such as carbon &
charcoal
G
Non-conductive dusts, such as flour, grain,
wood & plastic
Class III, Division 1 & 2 None
Ignitable fibers/ flyings, such as cotton lint,
flax & rayon

44. GAS AND DUST GROUPS
NEC & IEC Zone System Gas & DustGroups
Area Group Representative Materials
Zone 0, 1 & 2
IIC Acetylene & Hydrogen(equivalent to NEC Class I, Groups A and B)
IIB+H2 Hydrogen(equivalent to NEC Class I, Group B)
IIB Ethylene(equivalent to NEC Class I, Group C)
IIA Propane(equivalent to NEC Class I, Group D)
Zone 20, 21 & 22
IIIC Conductive dusts, such as magnesium(equivalent to NEC Class II, Group E)
IIIB
Non-conductive dusts, such as flour, grain, wood & plastic(equivalent to NEC Class
II, Groups F and G)
IIIA Ignitable fibers/ flyings, such as cotton lint, flax & rayon(equivalent to NEC Class III
Mines susceptible to
firedamp
I (IEC only) Methane
Group IIC is the most severe Zone system gas group. Hazards in this group gas can be ignited very easily indeed. Equipment marked
as suitable for Group IIC is also suitable for IIB and IIA. Equipment marked as suitable for IIB is also suitable for IIA but NOT for IIC. If
equipment is marked, for example, Ex e II T4 then it is suitable for all subgroups IIA, IIB and IIC .

45. TEMPERATURE CLASS
• The temperature class of a gas/ vapour is given in the following table. To avoid the danger of explosion, equipment required
for use in the particular gas or vapour atmosphere should be in accordancewith the temperatureclass of the gas or vapour.
• In electrical design, a hazardouslocation (sometimes abbreviated to HAZLOC) is defined as a place where concentrationsof
flammable gases, vapors,or dusts occur. Electrical equipment that must be installed in such locations is especially designed
and tested to ensure it does not initiate an explosion, due to arcing contactsor high surface temperature of equipment.
Temperature class Range of auto-ignition temperature (AIT) (°C)
T1 ≥450
T2 300 < AIT ≤ 450
T3 200 < AIT ≤ 300
T4 135 < AIT ≤ 200
T5 100 < AIT ≤ 135
T6 85 < AIT ≤ 100

46. SELECTION OF ELECTRICAL EQUIPMENT PER ZONE
• Indian statutory and regulatory organizations like PESO and BIS as well as consultants follow the Indian Standard IS 5571-2009 “Guide for
Selection and Installation of Electrical Equipment in Hazardous Areas (other than Mines)” for selecting and installing equipment in
hazardous locations.
• The following table lists the equipment type of protection and its suitability for the appropriate hazardous location.
Type of Protection Relevant Standard Suitable for Zone
Intrinsically Safe Ex ia IS/IEC 60079-11- 2006 Zone 0, 1 and 2
Intrinsically Safe Ex ib IS/IEC 60079-11- 2006 Zone 1 and 2
Flameproof Enclosures Ex d IS/IEC 60079-1-2007 Zone 1 and 2
Pressurized or Purged Ex p IS/IEC 60079-2 - 2007 Zone 1 and 2
Encapsulation Ex m IS/IEC 60079-18-2004 Zone 1 and 2
Powder Filled Ex q IS/IEC 60079-5 - 2007 Zone 1 and 2
Oil Immersed Ex o IS 7693 IEC 60079-6-1995 Zone 1 and 2
Increased Safety Ex e IS/IEC 60079-7-2006 Zone 2
Non-sparking Ex n IS/IEC 60079-15-2005 Zone 2

47. EXAMPLE:
• INDUCTION MOTORS FOR HAZARDOUS AREA :
TYPE OF CONSTRUCTION FLAMEPROOF TYPE Ex-'d' – Energy
Efficient (IE2)- Suitable for continuous
operation
CLASS OF INSULATION F WITH TEMP. RISE CLASS-B
MAXIMUM SURFACE TEMPERATURE CLASSIFICATION (IS:8239) T3
LOCATION Indoor/Outdoor (*)
A ) HAZARDOUS AREA DIVISION ZONE 2
B) GROUP CLASSIFACTION AS PER IS:2148 (FOR FLAMEPROOF
ENCLOSURES HAVING HAZARDOUS GAS)
IIA/IIB
C ) WHETHER SUITABILITY FOR HAZARDOUS DUST REQUIRED IF
YES, TYPE OF DUST
NO
ATMOSPHERE Chemical
DESIGNATION FOR DEGREE OF PROTECTION (IS:4691):
IP41/IP43/IP54/IP55
IP-55

48. Thank you !
48
DEEPAK SINGH
9634844138