chiranjeevi ppt

8/7/2019 CHIRANJEEVI PPT

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PRESENTED BY,

CHIRANJEEVI

07L31A0219

III/IV B.TECH, E.E.E

VIGNANS INSTITUTE OF INFORMATION ANDTECHNOLOGY


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Over view;-

Purpose

Introduction

Places where hazardscan occur.

The Dangers

Prevention

Summary Conclusions


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Purpose

The purpose safety and prevention

Raising your awareness of electrical hazards

Instructing you on how to recognize electrical

hazards

Providing ways to eliminate, remove andprevent electrical hazards in the workplace

Emphasizing the extreme importance ofobserving all electrical safety requirements andpractices

Instructing you on what to do during anelectrical accident.


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Hazard: simply means DANGER

Electrical Hazard A dangerous

condition such that contact orequipment failure can result in

electric shock, arc-flash burn,thermal burn, or blast.

INTRODUCTION:-


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Why should you be concerned

aboutelectrical hazards?

Electricity has long been recognizedas a serious workplace hazard,exposing employees to electricshock, electrocution, burns, fires,and explosions.

Many people working in the field ofelectricity have lost their life orbadly injured, next it may be yourturn if you are not cautious.


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Just asecondofcontactoflive wire

canresultasthis


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Cont..

An average of one worker is electrocutedon the job every day

An average of one person is electrocuted

in the home every 36 hours Electrical incidents are far more likely to

be fatal than other types There are four main types of electrical

injuries:

Electrocution (death due to electrical shock) Electrical shock Burns Falls


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Received when current passesthrough the body

Severity of the shock depends

on:

Path of current through thebody

Amount of current flowingthrough the body

Length of time the body is inthe circuit

Electrical Shock


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How isanelectricalshock

received?

When two wires have different potentialdifferences (voltages), current will flow ifthey are connected together

In most household wiring, the black wires areat 230 volts relative to ground The white/red wires are at zero volts because

they are connected to ground

If you come into contact with anenergized (live) black wire, and you are

also in contact with the white groundedwire, current will pass through your bodyand YOU WILL RECEIVE A SHOCK


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How isanelectricalshock

received? (contd)

If you are in contact with an energized wireor any energized electrical component, andalso with any grounded object, YOU WILL

RECEIVE A SHOCK You can even receive a shock when you are

not in contact with a ground

If you contact both wires of a 240-voltcable, YOU WILL RECEIVE A SHOCK and

possibly be electrocuted


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Low Voltage Does Not MeanLow

Hazard

A small amount of electrical current cancause injury, even death

The current from a 7.5-watt, 120-voltlamp, passing across the chest, isenough to cause fatal electrocution

Deaths from 110 volts represent about 12percent of all electrocutions in the world

(rough data)


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Dry Conditions Human Skin is ResistantCurrent = Volts/Ohms = 120/100,000 = 1mA(0.001A)Barely perceptible level of current

Wet Conditions Skins Resistance dropsdramatically

Current = Volts/Ohms = 120/1,000 = 120mA(0.12A)

-Sufficient current to cause ventricular fibrillation

A low voltage electrocution becomes much morehazardous in a wet condition

High voltage electrical energy greatly reduces the body's resistance by quicklyHigh voltage electrical energy greatly reduces the body's resistance by quickly

breaking down human skin. Once the skin is punctured, the lowered resistancebreaking down human skin. Once the skin is punctured, the lowered resistance

results in massive current flow.results in massive current flow.

Human Skin & Resistance


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How Electric Current Affects the Body

Note: some smaller microwave ovens use 10.0 Amps (10,000 milliamps) and common

florescent lights use 1 Amp (1,000 milliamps)

Current

(Amps) Human Reaction

0.001 Perception level. Just a faint tingle.

0.005 Slight shock felt; not painful but disturbing.Average individual can let go.

0.006-0.025(Women) Painful shock, muscular control is lost.

0.009-0.030 (Men) This is called the freezing current or "let-go"range.

0.050-0.150 Extreme pain, respiratory arrest, severe

muscular contractions.

1 - 4.3 Ventricular fibrillation.

10 Cardiac arrest, severe burns and probabledeath.


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Few photosofinjuriesduetoelectrical

shock-


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Places where hazards canoccur.

It can be at your home

Work place

Transmission lines Jumbled wires on a distribution line.

Sub stations

Transformers malfunctioning

and any place where there iselectricity there can b a hazard.


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Jaipur:


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New Delhi


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Vizag


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Hazard - OverheadPowerLines

Usually not insulated

Examples of equipment that cancontact power lines:

CraneLadderScissors liftRaised dump truck bedbore drill truck etc.


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Arc Flash Protection BoundaryArc Flash Protection Boundary

Voltage Boundary

up to 750V 3 feet

750V to 2kV 4 feet

2kV to 15kV 16 feet

15kV to 36kV 19 feet

over 36kV Must be Calculated


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RecognizetheHazards beforethey

happen


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Junction boxes, pull boxes and fittings musthave approved covers in place

Unused openings in cabinets, boxes and

fittings must be closed. Electrical equipment and wiring must not

be exposed to physical damage

Stay away from damaged equipment

Treat the electrical equipment as it isdesigned to be treated

Pull the plug, not the cord

RecognizetheHazard

Cabinets, Boxes,andFittings


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Do not fasten electrical cords to surfaceswith staples, nails, wire, or any othermethod that might damage the cord

Extension cords Place them in appropriate locations

Understand they are for temporary use only

Tool cords Keep track of them, to assure they do not

become damaged

Do not plug or unplug electrical cords withwet hands or while standing in water

SafePractices


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Do not remove/replace receptacle covers,switch plates, or covers of electricalequipment that may contain energized

conductors without electrical qualificationsand authorization

Only qualified electrical workers mayperform activities such as electrical

probing, measuring and testing electricalenergized components (such asperforming an absence of voltage test)

SafePractices

Qualifications


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BurjAlArab megastructure

World class mega

structure has the

world class solutionfor electrical hazard.


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Attempts to rescue an accident victimmay pose as great a hazard for therescuer as it does for the victim

A victim of an electrical accident isoften unable to move or release theelectrical conductor, because of muscleclamping

Caution should be a primaryconsideration during any electricalaccident or emergency

ElectricalEmergencies


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Never rush into an accident situation-Assess your ownsafety

Call for help as soon as possible

Unplug portable electrical equipment to remove power

(1st choice)

Open a disconnecting device or circuit breaker to de-energize fixed electrical equipment

Use a dry wood broom, leather belt, plastic rope, orsomething similar that is non-conductive such as woodor plastic cane with hook on the end to free the personfrom the energy source

ElectricalEmergencies


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Inspect your work areas Existing unsafe conditions

- Bare wires

- Open enclosures containing exposed wires- Loose or missing covers or fasteners

- Use good electrical safe practices- No overloading outlets

- Pull on plug, not cord

- When unsafe electrical conditions are found,correct them if possible, or take steps to warnothers.

What youmustdo Now?


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Summary Hazards & Protections

Hazards

Inadequate wiring

Exposed electrical parts

Wires with bad insulation Ungrounded electrical systems and tools

Overloaded circuits

Damaged power tools and equipment

Using the wrong tools

Overhead power lines All hazards are made worse in wet conditions


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Summary -

Protective Measures

Proper grounding

Use proper tools

Use fuses and circuit breakers

Guard live parts

Lock out

Proper use of flexible cords

Close electric panels

Training/knowledge of hazards


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Electricalsafety equipments


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Electricity is like a double edgeknife, use it carefully to live a better

life, a small carelessness can causeheavy unrepayable damage.

Electrical hazard can only be

prevented, it cannot be cured.


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ANY

QUERIES??


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