1. Controlling Electrical Hazards.

8/8/2019 1. Controlling Electrical Hazards.

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Presentation byPresentation byEr. C.P.GeorgeEr. C.P.George

CONTROLLINGCONTROLLING

ELECTRICAL HAZARDS.ELECTRICAL HAZARDS.


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CONTROLLINGCONTROLLING

ELECTRICAL HAZARDS.ELECTRICAL HAZARDS.


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--BODYBODY

How Electricity Acts?How Electricity Acts?Electric Hazards.Electric Hazards.

How Shock Occurs?How Shock Occurs?The Severity of ShockThe Severity of ShockEffect of Electric Current inEffect of Electric Current in

Human Body.Human Body.InjuriesInjuries


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ELECTRIC HAZARDSELECTRIC HAZARDS

InsulationInsulationGuardingGuarding

GroundingGroundingProtective DevicesProtective DevicesSafe Work PracticesSafe Work Practices

TrainingTrainingGood Judgments.Good Judgments.


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HOW TO PRACTICEHOW TO PRACTICE

Assess the RiskAssess the RiskRisk assessment methodsRisk assessment methodsHarsh conditionsHarsh conditionsRisky itemsRisky itemsReducing the Risk:Reducing the Risk:a. In under ground power cablesa. In under ground power cablesb. Over head power linesb. Over head power linesc.Electrified railways and tramways.c.Electrified railways and tramways.


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HOW ELECTRICITYHOW ELECTRICITY

ACTSACTSOperating an electricOperating an electric

switch may beswitch may be

considered analogous toconsidered analogous to

turning on a water faucet.turning on a water faucet.


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ACTS ..ACTS ..

In the case of water, theIn the case of water, thesource is a reservoir or source is a reservoir or

pumping station; thepumping station; thetransportation is throughtransportation is throughpipes; and the force to makepipes; and the force to make

it flow is pressure, providedit flow is pressure, providedby a pump.by a pump.


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For electricity, the source isFor electricity, the source isthe power generatingthe power generating

station; current travelsstation; current travelsthrough electric conductorsthrough electric conductorsin the form of wires; andin the form of wires; and

pressure, measured in volts,pressure, measured in volts,is provided by a generator.is provided by a generator.


ACTSACTS - - -- --


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ACTS.ACTS.Resistance to the flow of electricityResistance to the flow of electricity

is measured in ohms and variesis measured in ohms and varies

widely. It is determined by threewidely. It is determined by threefactors: the nature of the substancefactors: the nature of the substance

itself, the length and crossitself, the length and cross- -sectionalsectional

area (size) of the substance, and thearea (size) of the substance, and the

temperature of the substance.temperature of the substance.


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Some substances, such as metals,Some substances, such as metals,offer very little resistance to the flowoffer very little resistance to the flowof electric current and are calledof electric current and are calledconductors. Other substances, suchconductors. Other substances, suchas bakelite, porcelain, pottery, andas bakelite, porcelain, pottery, anddry wood, offer such a highdry wood, offer such a high

resistance that they can be used toresistance that they can be used toprevent the flow of electric currentprevent the flow of electric currentand are called insulators.and are called insulators.


ACTSACTS


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HOW ELECTRICITYHOW ELECTRICITYACTSACTS

Dry wood has a highDry wood has a highresistance, but whenresistance, but whensaturated with water, itssaturated with water, itsresistance drops to theresistance drops to thepoint where it will readilypoint where it will readilyconduct electricity.conduct electricity.The same thing is true of The same thing is true of human skin.human skin.


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When it is dry, skin has a fairly highWhen it is dry, skin has a fairly highresistance to electric current; butresistance to electric current; butwhen it is moist, there is a radicalwhen it is moist, there is a radicaldrop in resistancedrop in resistance ..Pure water is a poor conductor, butPure water is a poor conductor, butsmall amounts of impurities, such assmall amounts of impurities, such assalt and acid (salt and acid ( both of which areboth of which are

contained in perspiration),contained in perspiration), make it amake it aready conductor.ready conductor.

ACTSACTS


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HOW ELECTRICITY ACTSHOW ELECTRICITY ACTS

When water is present either When water is present either in the environment or on thein the environment or on theskin, anyone working withskin, anyone working withelectricity should exerciseelectricity should exercise

even more caution than theyeven more caution than theynormally would.normally would.


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HAZARDSHAZARDS

ELECTROCUTIONELECTROCUTION

ELECTRIC SHOCKELECTRIC SHOCK

BURNSBURNS

FIRESFIRES

EXPLOSIONEXPLOSION


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HOW SHOCK OCCURS?HOW SHOCK OCCURS?

Electric shock occurs whenElectric shock occurs whenthe body becomes a part of the body becomes a part of the electric circuit. Thethe electric circuit. Thecurrent must enter the bodycurrent must enter the body

at one point and leave atat one point and leave atanother.another.


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Electric shock normally occurs inElectric shock normally occurs inone of three ways. Individualsone of three ways. Individuals whilewhilein contact with the groundin contact with the ground

1. must come in contact with both1. must come in contact with bothwires of the electric circuitwires of the electric circuit

2. one wire of an energized circuit or 2. one wire of an energized circuit or

3. a metallic part that has become3. a metallic part that has becomehot by contact with an energizedhot by contact with an energizedconductor.conductor.

HOW SHOCK OCCURS?HOW SHOCK OCCURS?


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GROUNDING PROTECTIONGROUNDING PROTECTION

In case 3 the worker using theseIn case 3 the worker using these

tools and machines is made lesstools and machines is made less

vulnerable to electric shock whenvulnerable to electric shock when

there is a low resistance path fromthere is a low resistance path from

the metallic case of the tool or the metallic case of the tool or machine to the ground.machine to the ground.


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This is done through the use of anThis is done through the use of anequipment grounding conductor equipment grounding conductor a a

lowlow- -resistance wire that causes theresistance wire that causes theunwanted current to pass directly tounwanted current to pass directly tothe ground, thereby greatly reducingthe ground, thereby greatly reducingthe amount of current passingthe amount of current passingthrough the body of the person inthrough the body of the person incontact with the tool or machine.contact with the tool or machine.



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If the equipmentIf the equipmentgrounding conductor hasgrounding conductor hasbeen properly installed, itbeen properly installed, ithas a low resistance tohas a low resistance to

ground, and the worker isground, and the worker isprotected.protected.



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SHOCKSHOCK

The severity of the shock receivedThe severity of the shock receivedwhen a person becomes a part of anwhen a person becomes a part of an

electric circuit is affected byelectric circuit is affected by1. the amount of current flowing1. the amount of current flowingthrough the body (measured inthrough the body (measured inamperes)amperes)

2. the path of the current through the2. the path of the current through thebodybody3. the length of time the body is in3. the length of time the body is inthe circuitthe circuit


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THE SEVERITY OFTHE SEVERITY OFSHOCK..SHOCK..

Other factors that may affect theOther factors that may affect theseverity of shock are the frequencyseverity of shock are the frequency

of the current, the phase of the heartof the current, the phase of the heartcycle when shock occurs, and thecycle when shock occurs, and thegeneral health of the person.general health of the person.

The effects of electric shock dependThe effects of electric shock dependupon the type of circuit, its voltage,upon the type of circuit, its voltage,resistance, current, pathway throughresistance, current, pathway throughthe body, and duration of thethe body, and duration of thecontact.contact.


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Effects can range from a barelyEffects can range from a barelyperceptible tingle to immediateperceptible tingle to immediate

cardiac arrest.cardiac arrest.There are no absolute limits or There are no absolute limits or even known values that showeven known values that show

the exact injury from anythe exact injury from anygiven currentgiven current


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EFFECT OF CURRENT IN HUMAN BODY.EFFECT OF CURRENT IN HUMAN BODY. [Hand to foot[Hand to footpath and one second duration for 60Hz]path and one second duration for 60Hz]

1 Milliamps1 Milliamps Perception level. Just a faint tingle.Perception level. Just a faint tingle.

5 Milliamps5 MilliampsSlight shock felt: not painful but disturbing. AverageSlight shock felt: not painful but disturbing. Average

individual can let go.individual can let go.

66--25 Milliamps25 Milliamps[women][women]

Painful Shock, muscular control is lost.Painful Shock, muscular control is lost.

99--30 Milliamps30 Milliamps[men][men]

This is called the freezing current or letThis is called the freezing current or let- -go range.go range.

5050--150 Milliamps150 MilliampsExtreme pain, respiratory arrest, severe muscularExtreme pain, respiratory arrest, severe muscular

contractions. Individual cannot let go. Death iscontractions. Individual cannot let go. Death ispossible.possible.

10001000- -43004300MilliampsMilliamps

Ventricular fibrillation. [The rhythmic pumping actionVentricular fibrillation. [The rhythmic pumping actionof the heart ceases.] Muscular contraction andof the heart ceases.] Muscular contraction and

nerve damage occur. Death is most likely.nerve damage occur. Death is most likely.

10000 Milliamps10000 Milliamps Cardiac arrest, severe burns and probable death.Cardiac arrest, severe burns and probable death.


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THE SEVERITY OF SHOCKTHE SEVERITY OF SHOCK[[TABLETABLE- - ANALYSIS]ANALYSIS]

The table also illustrates thatThe table also illustrates that aadifference of less than 100 milliampsdifference of less than 100 milliamps

exists between a current that isexists between a current that isbarely perceptible and one that canbarely perceptible and one that cankillkillMuscular contraction caused byMuscular contraction caused bystimulation may not allow the victimstimulation may not allow the victimto free himself or herself from theto free himself or herself from thecircuit, andcircuit, and the increased duration of the increased duration of exposure increases the dangers toexposure increases the dangers tothe shock victim.the shock victim.


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a current of 100 milliampsa current of 100 milliampsfor 3 seconds is equivalentfor 3 seconds is equivalentto a current of 900 milliampsto a current of 900 milliampsapplied for .03 seconds inapplied for .03 seconds in

causing ventricular causing ventricular fibrillationfibrillation



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THE SEVERITY OF SHOCKTHE SEVERITY OF SHOCK

LOW VOLTAGE DOES NOT IMPLYLOW VOLTAGE DOES NOT IMPLYLOW HAZARD!LOW HAZARD!A severe shock can causeA severe shock can causeconsiderably more damage to theconsiderably more damage to thebody than is visible. For example,body than is visible. For example,

a person may suffer internala person may suffer internalhemorrhages and destruction of hemorrhages and destruction of tissues, nerves, and muscles.tissues, nerves, and muscles.


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Shock is often only theShock is often only thebeginning in a chain of beginning in a chain of events. The final injuryevents. The final injurymay well be from a fall,may well be from a fall,

cuts, burns, or brokencuts, burns, or brokenbones.bones.

SHOCKSHOCK


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BURNS AND OTHER INJURIESBURNS AND OTHER INJURIES

The most common shockThe most common shock- -relatedrelatedinjury is a burn.injury is a burn.

Burns suffered in electricalBurns suffered in electricalaccidents may be of three types:accidents may be of three types:1. electrical burns1. electrical burns

2. arc burns, and2. arc burns, and3.thermal contact burns.3.thermal contact burns.


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ELECTRIC BURNSELECTRIC BURNS

Electrical burns are the result of Electrical burns are the result of the electric current flowingthe electric current flowing

through tissues or bone.through tissues or bone.Tissue damage is caused by theTissue damage is caused by theheat generated by the currentheat generated by the currentflow through the body.flow through the body.Electrical burns are one of theElectrical burns are one of themost serious injuries you canmost serious injuries you canreceive and should be givenreceive and should be given

immediate attention.immediate attention.


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THERMAL CONTACT BURNSTHERMAL CONTACT BURNS

The thermal contact burns are thoseThe thermal contact burns are thosenormally experienced when the skinnormally experienced when the skin

comes in contact with hot surfacescomes in contact with hot surfacesof overheated electric conductors,of overheated electric conductors,conduits, or other energizedconduits, or other energizedequipment.equipment.

Additionally, clothing may be ignitedAdditionally, clothing may be ignitedin an electrical accident and ain an electrical accident and athermal burn will resultthermal burn will result


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ARC OR FLASH BURNSARC OR FLASH BURNS

Arc or flash burns, on the other Arc or flash burns, on the other hand, are the result of highhand, are the result of high

temperatures near the body andtemperatures near the body andare produced by an electric arcare produced by an electric arcor explosion.or explosion.

They should also be attended toThey should also be attended topromptly.promptly.


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SECONDARY INJURIES..SECONDARY INJURIES..

In addition to shock and burnIn addition to shock and burnhazards, electricity poses other hazards, electricity poses other dangers. For example, when adangers. For example, when ashort circuit occurs, hazards areshort circuit occurs, hazards arecreated from the resulting arcs. If created from the resulting arcs. If high current is involved, these arcshigh current is involved, these arcscan cause injury or start a fire.can cause injury or start a fire.


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SECONDARY INJURIESSECONDARY INJURIES

Extremely high energy arcs canExtremely high energy arcs candamage equipment, causingdamage equipment, causingfragmented metal to fly in allfragmented metal to fly in alldirections. Even lowdirections. Even low- -energy arcsenergy arcscan cause violent explosions incan cause violent explosions inatmospheres that containatmospheres that contain

flammable gases, vapors, or flammable gases, vapors, or combustible dusts.combustible dusts.


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PREVENTINGPREVENTINGELECTRICAL HAZARDSELECTRICAL HAZARDS

These include:These include:1. insulation,1. insulation,

2. guarding,2. guarding,3. grounding,3. grounding,4. electrical protective4. electrical protectivedevices, anddevices, and5. safe work practices5. safe work practices


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INSULATIONINSULATION

. Before employees prepare to work. Before employees prepare to workwith electric equipment, it iswith electric equipment, it is

always a good idea for them toalways a good idea for them tocheck the insulation before makingcheck the insulation before makinga connection to a power source toa connection to a power source tobe sure there are no exposed wiresbe sure there are no exposed wiresThe insulation of flexible cords,The insulation of flexible cords,such as extension cords, issuch as extension cords, isparticularly vulnerable to damage.particularly vulnerable to damage.


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INSULATIONINSULATION

Also, the insulation should beAlso, the insulation should besuitable for the voltage andsuitable for the voltage andexisting conditions, such asexisting conditions, such astemperature, moisture, oil,temperature, moisture, oil,gasoline, or corrosive fumes.gasoline, or corrosive fumes.The ungrounded conductors, or The ungrounded conductors, or hot wires, may be any color hot wires, may be any color other than green, white, or gray.other than green, white, or gray.


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GUARDINGGUARDING

Live parts of electricLive parts of electricequipment operating at 50equipment operating at 50volts or more must bevolts or more must beguarded against accidentalguarded against accidentalcontactcontact

location in a room, vault, or location in a room, vault, or similar enclosure accessiblesimilar enclosure accessibleonly to qualified persons;only to qualified persons;


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GUARDING ..GUARDING ..

use of permanent, substantialuse of permanent, substantialpartitions or screens to excludepartitions or screens to excludeunqualified persons;unqualified persons;location on a suitable balcony,location on a suitable balcony,

gallery, or platform elevated andgallery, or platform elevated andarranged to exclude unqualifiedarranged to exclude unqualifiedpersons; or persons; or elevation of 8 feet (2.44 meters)elevation of 8 feet (2.44 meters)or more above the floor.or more above the floor.


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GUARDING ..GUARDING ..

Entrances to rooms and other Entrances to rooms and other

guarded locations containingguarded locations containingexposed live parts must beexposed live parts must be

marked with conspicuousmarked with conspicuous

warning signs forbiddingwarning signs forbidding

unqualified persons to enter.unqualified persons to enter.


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GUARDING GUARDING

Indoor electric wiring more than 600Indoor electric wiring more than 600volts and that is open to unqualifiedvolts and that is open to unqualifiedpersons must be made with metalpersons must be made with metal- -enclosed equipment or enclosed in aenclosed equipment or enclosed in avault or area controlled by a lock.vault or area controlled by a lock.

In addition, equipment must beIn addition, equipment must bemarked with appropriate cautionmarked with appropriate cautionsigns.signs.


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GROUNDINGGROUNDING

It is normally a secondaryIt is normally a secondary

protective measure.protective measure.By grounding a tool or By grounding a tool or

electrical system, a lowelectrical system, a low- -

resistance path to the earth isresistance path to the earth isintentionally created.intentionally created.


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GROUNDING ..GROUNDING ..

The term ground refers to aThe term ground refers to aconductive body, usually theconductive body, usually theearth, and means a conductiveearth, and means a conductiveconnection, whether intentionalconnection, whether intentionalor accidental, by which anor accidental, by which anelectric circuit or equipment iselectric circuit or equipment is

connected to earth or theconnected to earth or theground plane.ground plane.


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GROUNDING GROUNDING

. When properly done, this path. When properly done, this path

offers sufficiently low resistance andoffers sufficiently low resistance andhas sufficient current carryinghas sufficient current carrying

capacity to prevent the buildup of capacity to prevent the buildup of

voltages that may result in avoltages that may result in apersonnel hazardpersonnel hazard


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This does not guarantee that noThis does not guarantee that noone will receive a shock, beone will receive a shock, beinjured, or be killed. It will,injured, or be killed. It will,however, substantially reducehowever, substantially reducethe possibility of suchthe possibility of suchaccidentsaccidents especially whenespecially whenused in combination with proper used in combination with proper safety measures.safety measures.

GROUNDING GROUNDING


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GROUNDINGGROUNDING- - TYPESTYPES

There are two kinds of There are two kinds of

grounds.grounds.

One of these is called theOne of these is called the

service or system ground.service or system ground.


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--System GroundSystem Ground

In this instance, one wireIn this instance, one wire called the neutral conductorcalled the neutral conductoror grounded conductoror grounded conductor is isgrounded.grounded.This type of ground is primarilyThis type of ground is primarilydesigned to protect machines,designed to protect machines,tools, and insulation againsttools, and insulation againstdamagedamage


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GROUNDING FORGROUNDING FOR

ENHANCED PROTECTIONENHANCED PROTECTIONTo offer enhanced protection toTo offer enhanced protection tothe workers themselves, anthe workers themselves, anadditional ground, called theadditional ground, called theequipment ground, must beequipment ground, must befurnished by providing another furnished by providing another

path from the tool or machinepath from the tool or machinethrough which the current canthrough which the current canflow to the ground.flow to the ground.


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GROUNDING & SAFETYGROUNDING & SAFETY

This additional groundThis additional groundsafeguards the electricsafeguards the electric

equipment operator in the eventequipment operator in the eventthat a malfunction causes thethat a malfunction causes themetal frame of the tool tometal frame of the tool tobecome accidentally energized.become accidentally energized.

The resulting heavy surgeThe resulting heavy surgeof current will then activate theof current will then activate thecircuit protection devices andcircuit protection devices andopen the circuitopen the circuit ..


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CIRCUIT PROTECTIONCIRCUIT PROTECTIONDEVICESDEVICES

Circuit protection devices areCircuit protection devices are

designed to automatically limitdesigned to automatically limitor shut off the flow of or shut off the flow of

electricity in the event of aelectricity in the event of agroundground- -fault, overload, or shortfault, overload, or short

circuit in the wiring system.circuit in the wiring system.


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PROTECTIVE DEVICESPROTECTIVE DEVICES

Fuses, circuit breakers, andFuses, circuit breakers, and

groundground- -fault circuitfault circuitinterrupters are three wellinterrupters are three wellknown examples of suchknown examples of suchdevices.devices.


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Fuses and circuitFuses and circuit- -breakers arebreakers areover over- -current devices that arecurrent devices that areplaced in circuits to monitor theplaced in circuits to monitor theamount of current that theamount of current that thecircuit will carry.circuit will carry.

They automatically openThey automatically openor break the circuit when theor break the circuit when theamount of current flow becomesamount of current flow becomesexcessive and therefore unsafe.excessive and therefore unsafe.

PROTECTIVE DEVICESPROTECTIVE DEVICES


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FUSES & CIRCUITFUSES & CIRCUITBRAKERSBRAKERS

Fuses are designed to meltFuses are designed to meltwhen too much current flowswhen too much current flowsthrough them.through them.

Circuit breakers, onCircuit breakers, onthe other hand, are designedthe other hand, are designedto trip open the circuit byto trip open the circuit byelectroelectro- -mechanical means.mechanical means.


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BRAKERSBRAKERS

Fuses and circuit breakers areFuses and circuit breakers areintended primarily for theintended primarily for theprotection of conductors andprotection of conductors andequipment.equipment.They prevent overheating of They prevent overheating of wires and components thatwires and components that

might otherwise create hazardsmight otherwise create hazardsfor operators.for operators.


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GROUND FAULTGROUND FAULT

CIRCUIT INTERRUPTERCIRCUIT INTERRUPTERThe groundThe ground- -fault circuit interrupter, or fault circuit interrupter, or

GFCI, is designed to shutoff electricGFCI, is designed to shutoff electric

power within as little as 1/40 of apower within as little as 1/40 of asecond.second.It works by comparing the amount of It works by comparing the amount of

current going to electric equipmentcurrent going to electric equipmentagainst the amount of current returningagainst the amount of current returningfrom the equipment along the circuitfrom the equipment along the circuitconductors.conductors.


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INTERUPTERINTERUPTER

If the current difference exceeds 6If the current difference exceeds 6

milliamps, the GFCI interrupts themilliamps, the GFCI interrupts the

current quickly enough to preventcurrent quickly enough to preventelectrocution.electrocution.

The GFCI is used in highThe GFCI is used in high- -risk areasrisk areas

such as wet locations andsuch as wet locations andconstruction sites.construction sites.


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SAFE WORK PRACTICESSAFE WORK PRACTICES

DeDe--energizing electric equipmentenergizing electric equipmentbefore inspecting or making repairsbefore inspecting or making repairs

Using electric tools that are in goodUsing electric tools that are in goodrepair repair

Using good judgment when workingUsing good judgment when working

near energized lines, andnear energized lines, andUsing appropriate protectiveUsing appropriate protectiveequipment.equipment.


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SAFE WORK PRACTICESSAFE WORK PRACTICES

Electrical safetyElectrical safety- -relatedrelated

work practice requirementswork practice requirements

are to be strictly adopted asare to be strictly adopted as

per the issued manuals.per the issued manuals.

DEDE ENERGISINGENERGISING


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DEDE--ENERGISINGENERGISINGELECTRICAL EQUIPMENTELECTRICAL EQUIPMENT

The accidental or The accidental or

unexpected suddenunexpected sudden

starting of electricalstarting of electrical

equipment can causeequipment can cause

severe injury or death.severe injury or death.

DEDE ENERGISINGENERGISING


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Before ANY inspections or Before ANY inspections or

repairs are maderepairs are made even on theeven on the

soso- -called lowcalled low- -voltage circuitsvoltage circuits the current must be turned off atthe current must be turned off at

the switch box and the switchthe switch box and the switch

padlocked in the OFF position.padlocked in the OFF position.

DEDE--ENERGISINGENERGISINGELECTRICAL EQUIPMENTELECTRICAL EQUIPMENT


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DEDE--ENERGISINGENERGISING

At the same time, the switch or At the same time, the switch or

controls of the machine or other controls of the machine or other

equipment being locked out of equipment being locked out of service must be securely taggedservice must be securely tagged

to show which equipment or to show which equipment or

circuits are being worked on.circuits are being worked on.


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MAINTENANCE WORKSMAINTENANCE WORKS

Maintenance employees shouldMaintenance employees shouldbe qualified for the work whobe qualified for the work who

have been well instructed inhave been well instructed inlockout procedures.lockout procedures.No two locks should be alike;No two locks should be alike;each key should fit only oneeach key should fit only one

lock, and only one key should belock, and only one key should beissued to each maintenanceissued to each maintenanceemployee.employee.


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MAINTENANCE WORKMAINTENANCE WORK

If more than one employee isIf more than one employee isrepairing a piece of equipment, eachrepairing a piece of equipment, eachshould lock out the switch with his or should lock out the switch with his or

her own lock and never permither own lock and never permitanyone else to remove it.anyone else to remove it.The maintenance worker should atThe maintenance worker should atall times be certain that he or she isall times be certain that he or she isnot exposing other employees tonot exposing other employees todanger.danger.


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OVERHEAD LINESOVERHEAD LINES

If work is to be performed near If work is to be performed near overhead power lines, the lines must beoverhead power lines, the lines must be

dede- -energized and grounded by theenergized and grounded by theowner or operator of the lines, or other owner or operator of the lines, or other protective measures must be providedprotective measures must be providedbefore work is started.before work is started.

Protective measures (such as guardingProtective measures (such as guardingor insulating the lines) must beor insulating the lines) must bedesigned to prevent employees fromdesigned to prevent employees fromcontacting the lines.contacting the lines.


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OVERHEAD LINES ..OVERHEAD LINES ..

Unqualified employees andUnqualified employees andmechanical equipment mustmechanical equipment must

stay at least 10 feet (3.05stay at least 10 feet (3.05meters) away from overheadmeters) away from overheadpower lines. If the voltage ispower lines. If the voltage ismore than 50,000 volts, themore than 50,000 volts, the

clearance must be increased byclearance must be increased by4 inches (10 centimeters) for 4 inches (10 centimeters) for each additional 10,000 volts.each additional 10,000 volts.


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OH LINESOH LINES

When mechanical equipment isWhen mechanical equipment isbeing operated near overheadbeing operated near overheadlines, employees standing on thelines, employees standing on theground may not contact theground may not contact theequipment unless it is locatedequipment unless it is locatedso that the required clearanceso that the required clearance

cannot be violated even at thecannot be violated even at themaximum reach of themaximum reach of theequipment.equipment.


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EQUIPMENTSEQUIPMENTS

Employees whose occupationsEmployees whose occupationsrequire them to work directly withrequire them to work directly withelectricity must use the personalelectricity must use the personal

protective equipment required for theprotective equipment required for the jobs they perform. jobs they perform.This equipment may consist of This equipment may consist of rubber insulating gloves, hoods,rubber insulating gloves, hoods,

sleeves, matting, blankets, line hose,sleeves, matting, blankets, line hose,and industrial protective helmets.and industrial protective helmets.


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TOOLSTOOLS

To maximize his or her ownTo maximize his or her ownsafety, an employee shouldsafety, an employee shouldalways use tools that workalways use tools that workproperly.properly.Tools must be inspectedTools must be inspected

before use, and those foundbefore use, and those foundquestionable, removed fromquestionable, removed fromservice and properly taggedservice and properly tagged ..


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TOOLS ..TOOLS ..

Tools and other equipment shouldTools and other equipment should

be regularly maintained.be regularly maintained.Inadequate maintenance canInadequate maintenance can

cause equipment to deteriorate,cause equipment to deteriorate,

resulting in an unsafe condition.resulting in an unsafe condition.


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Tools that are used byTools that are used by

employees to handle energizedemployees to handle energized

conductors must be designedconductors must be designedand constructed to withstandand constructed to withstand

the voltages and stresses tothe voltages and stresses to

which they are exposed.which they are exposed.

TOOLS ..TOOLS ..


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TRAININGTRAINING

To ensure that they use safeTo ensure that they use safe

work practices, employeeswork practices, employeesmust be aware of the electricalmust be aware of the electrical

hazards to which they will behazards to which they will be

exposed.exposed.


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Employees must be trained inEmployees must be trained in

safetysafety- -related work practices asrelated work practices as

well as any other procedureswell as any other proceduresnecessary for safety fromnecessary for safety from

electrical hazards.electrical hazards.

TRAININGTRAINING


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GOOD JUDGEMENTGOOD JUDGEMENT

Perhaps the single mostPerhaps the single most

successful defense againstsuccessful defense againstelectrical accidents is theelectrical accidents is thecontinuous exercising of continuous exercising of

good judgment or commongood judgment or commonsense.sense.


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GOOD JUDGEMENTGOOD JUDGEMENT

All employees should beAll employees should bethoroughly familiar with thethoroughly familiar with thesafety procedures for their safety procedures for their particular jobs. When a work isparticular jobs. When a work isperformed on an electricalperformed on an electricalequipment, the safety procedureequipment, the safety procedureshould be strictly followed.should be strictly followed.


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1. Have the equipment de1. Have the equipment de- -energized.energized.

2. Ensure that the equipment2. Ensure that the equipmentremains deremains de- -energized by usingenergized by usingsome type of lockout and tagsome type of lockout and tagprocedure.procedure.3. Use insulating protective3. Use insulating protectiveequipment.equipment.4. Keep a safe distance from4. Keep a safe distance from

energized parts.energized parts.

SAFETY PROCEDURESAFETY PROCEDURE


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ASSESSING THE RISKASSESSING THE RISK

HazardHazard means anythingmeans anythingwhich can cause harm.which can cause harm.

RiskRisk is the chance, great or is the chance, great or small, that someone willsmall, that someone willactually be harmed by theactually be harmed by thehazard.hazard.


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The first stage in controlling riskThe first stage in controlling riskis to carry out a risk assessmentis to carry out a risk assessment

in order to identify what needsin order to identify what needsto be done. (This is a legalto be done. (This is a legalrequirement for all risks atrequirement for all risks at

work.)work.)

ASSESSING THE RISKASSESSING THE RISK

RISK ASSESSMENTRISK ASSESSMENT


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RISK ASSESSMENTRISK ASSESSMENT- -METHODMETHOD

identify the hazards;identify the hazards;decide who might be harmed,decide who might be harmed,

and how;and how;evaluate the risks arising fromevaluate the risks arising fromthe hazards and decidethe hazards and decide

whether existing precautionswhether existing precautionsare adequate or more shouldare adequate or more shouldbe taken;be taken;


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RISK ASSESSMENTSRISK ASSESSMENTS

if you have five or moreif you have five or moreemployees, record anyemployees, record anysignificant findings;significant findings;

review your assessment fromreview your assessment fromtime to time and revise it if time to time and revise it if necessary.necessary.The risk of injury from electricityThe risk of injury from electricityis strongly linked to where andis strongly linked to where andhow it is used.how it is used.


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HARSH CONDTIONSHARSH CONDTIONS

The risks are greatest inThe risks are greatest inharsh conditionsharsh conditions- -

for example: in wetfor example: in wetsurroundingssurroundings - - unsuitableunsuitable

equipment can easilyequipment can easilybecome live and can makebecome live and can makeits surroundings liveits surroundings live


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HARSH CONDITIONSHARSH CONDITIONS

out of doorsout of doors - - equipment mayequipment maynot only become wet but may benot only become wet but may be

at greater risk of damage.at greater risk of damage.in cramped spaces with a lot of in cramped spaces with a lot of earthed metalwork, such asearthed metalwork, such asinside a tank or bininside a tank or bin - - if anif anelectrical fault developed itelectrical fault developed itcould be very difficult to avoid acould be very difficult to avoid ashock.shock.

RISKY ITEMSRISKY ITEMS


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Some items of equipment canSome items of equipment canalso involve greater risk thanalso involve greater risk than

others.others.Extension leads areExtension leads areparticularly liable to damageparticularly liable to damage - -

to their plugs and sockets, toto their plugs and sockets, totheir electrical connections,their electrical connections,and to the cable itself.and to the cable itself.


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Other flexible leads, particularlyOther flexible leads, particularly

those connected to equipmentthose connected to equipment

which is moved a great deal,which is moved a great deal,

can suffer from similar can suffer from similar

problems.problems.


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REDUCING THE RISKREDUCING THE RISK

Ensure that the electricalEnsure that the electricalinstallation is safeinstallation is safe

Provide safe and suitableProvide safe and suitableequipmentequipmentProvide a safety deviceProvide a safety deviceCarry out preventativeCarry out preventativemaintenancemaintenanceWork safelyWork safely

Underground powerUnderground power


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Underground power Underground power cablescables

Always assume cables will beAlways assume cables will bepresent when digging in thepresent when digging in the

street, pavement or near street, pavement or near buildings.buildings.Use upUse up- -toto--date service plans,date service plans,

cable avoidance tools andcable avoidance tools andsafe digging practice to avoidsafe digging practice to avoiddanger.danger.


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Overhead power linesOverhead power lines

When working near overheadWhen working near overheadlines, it may be possible tolines, it may be possible to

have them switched off if thehave them switched off if theowners are given enoughowners are given enoughnotice.notice.

If this cannot be done,If this cannot be done,consult the owners about theconsult the owners about thesafe working distance fromsafe working distance fromthe cables.the cables.


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OHOH-- POWER LINEPOWER LINE

Remember that electricity canRemember that electricity canflash over from overhead linesflash over from overhead lineseven though plant andeven though plant andequipment do not touch them.equipment do not touch them.Most of the fatal electricalMost of the fatal electrical

accidents each year are causedaccidents each year are caused

by contact with overhead lines.by contact with overhead lines.

Electrified railways andElectrified railways and


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yytramwaystramways

If working near electrifiedIf working near electrifiedrailways or tramways, consultrailways or tramways, consultthe line or track operatingthe line or track operatingcompany.company.Remember that some railwaysRemember that some railwaysand tramways use electrifiedand tramways use electrified

rails rather than overheadrails rather than overheadcables.cables.


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ConclusionConclusion. .

The control of electrical hazards isThe control of electrical hazards is

an important part of every safetyan important part of every safety

and health program.and health program.

The measures suggested hereThe measures suggested here

should be of help in establishingshould be of help in establishingsuch a program of control.such a program of control.


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The responsibility for this programThe responsibility for this program

should be delegated to individualsshould be delegated to individuals

who have a complete knowledge of who have a complete knowledge of electricity, electrical work practices,electricity, electrical work practices,

and the appropriate standards for and the appropriate standards for

installation and performanceinstallation and performance



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Everyone has the right to workEveryone has the right to workin a safe environment.in a safe environment.

Through cooperative efforts,Through cooperative efforts,employers and employees canemployers and employees canlearn to identify and eliminate or learn to identify and eliminate or

control electrical hazards.control electrical hazards.



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THANK YOUTHANK YOU

1. Controlling Electrical Hazards.

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Transcript of 1. Controlling Electrical Hazards.