ee safety report.ppt

8/19/2019 EE Safety Report.ppt

http://slidepdf.com/reader/full/ee-safety-reportppt 1/31

Safety



OSHAOSHA(Occupational Safety and Health(Occupational Safety and Health

Administration)Administration)



2 Main OSHA Rules2 Main OSHA Rulesthat pertain tothat pertain to

electrical safetyelectrical safety



NFPANFPA(National Fire Protection Association)(National Fire Protection Association)



NFPA

7!



"olta#e $et%een the feet of a personstandin# near an

!ner#i&ed #rounded o$'ects

S!PS!P

PO!N*A+PO!N*A+



is the ,olta#e di-erence $et%een the handsand feet of a person contactin# a structure.such as a pipeline

TOUCH TOUCH

POTENTIALPOTENTIAL



!lectricity is an apparent force in nature that!lectricity is an apparent force in nature that

e/ists %hene,er there is a net electricale/ists %hene,er there is a net electrical

char#e $et%een any t%o o$'ectschar#e $et%een any t%o o$'ects

0hen there are e1ual num$ers of positi,e0hen there are e1ual num$ers of positi,eand ne#ati,e char#es there is no electricaland ne#ati,e char#es there is no electrical

force as there is no net char#e his is theforce as there is no net char#e his is the

case for a neutral atomcase for a neutral atom

!lectrical force is created %hen electrons are!lectrical force is created %hen electrons are

transferred from one material to another (e#transferred from one material to another (e#

Fundamentals ofFundamentals of

electricityelectricity



onductoronductoris an o$'ect or type of materialthat allo%s the 3o% of electricalcurrent in one or more directions

A %ire is an electrical conductorthat can carry electricity alon#its len#th

Such as opper. or aluminum



*nsulator*nsulator*s a material %hose internalelectric char#es do not 3o%freely. and therefore ma4e itnearly impossi$le to conductan electric current under thein3uence of an electric 5eld



"olta#e"olta#e

electromoti,e force. is a1uantitati,e e/pression of

the potential di-erence inchar#e $et%een t%o points in an electrical 5eld



!lectric urrent!lectric urrent

is a 3o% of electric char#e*n electric circuits this char#e*s often carried $y mo,in#electrons in a %ire



!lectrical Resistance!lectrical Resistance

is a measure of the di6culty

to pass an electric currentthrou#h that conductor



!+!R*SHO

!+!R*A+89RNS

: MA*N ;P!S OF: MA*N ;P!S OF!+!R*A+!+!R*A+

A*<!NSA*<!NS



!+!R* SHO !+!R* SHO



!+!R*A+ 89RN!+!R*A+ 89RN



!+!R*A+ F*R!S!+!R*A+ F*R!S



H!R!=S A N9M8!R OF FAOR HA A9S!S !+!R*A+A*<!NS. * *N+9<!S>

O+< 0*R*N?S

POOR 0*R*N?S

+A OF PR!"!N*"! <!"*!S

F+AMMA8+! MA!R*A+S +!F N!AR !@POS!<!+!R*A+ 0*R*N?

!+!R*A+ A*<!N!+!R*A+ A*<!N

A9S!SA9S!S



PR!"!N*N?PR!"!N*N?!+!R*A+!+!R*A+

A*<!NSA*<!NS!+!R*A+ A*<!NS AN 8! PR!"!N!<

8;>

R!P+A*N? O+< AN< <AMA?!< 0*R*N?

H*R*N? A 9A+*F*!< !+!R**AN

NO O"!R+OA<*N? O9+!S*NSA++*N? ?RO9N< FA9+ *R9**N!RR9P!RS



Reco#ni&e Ha&ards!,aluate Ris4

ontrol Ha&ards

!lectrical Safety Model!lectrical Safety Model



hree Factors to determined the se,erity ofelectric shoc4>

he amount of currenthe path of current

he amount of time the current 3o%s

Se,erity of !lectricalSe,erity of !lectricalshoc4 shoc4



he Amount of urrenthe Amount of urrent

he amount of current that 3o%s throu#h the $ody is determined

$y the ,olta#e of the po%er source. the resistance of the $ody andthe amount of a,aila$le current



"olta#e is one of the factors %hichdetermined ho% much current %ill 3o% 8y

the Ohm=s +a%> "olta#e and current ha,e adirect proportional

Resistance of the human $ody can ,ary#reatlyB it depends on the part of $ody.the amount of $ody fat *nside the human$ody has a lo% resistance S4in is a

person=s last line of defense

he amount of a,aila$le current



urrent Pathurrent Path

here is a #reater chance of lethal in'ury%hen the current passes throu#h ,ital or#ansurrent that 3o%s near the heart may causethe heart to 5$rillate he current paths thatare most li4ely to cross the heart hand to

hand and hand to foot contact



+en#th of time+en#th of time

he lon#er a person has current 3o%in#throu#h their $ody the more dama#e %ill occur



ApplicationApplication

Fi,e technicians %ere performin# pre,enti,e

maintenance on the electrical system of arailroad maintenance facility One of thetechnicians %as assi#ned to clean the lo%ercompartment of an electrical ca$inet usin#

cleanin# 3uid in an aerosol can 8ut. he $e#an toclean the upper compartment as %ell he uppercompartment %as 5lled %ith li,e circuitry 0henthe cleanin# spray contacted the li,e circuitry. aconducti,e path for the current %as created



he current passed throu#h the streamof 3uid. into the technician=s arm. and

across his chest he current caused a loude/plosion oC%or4ers found the ,ictim %ithhis clothes on 5re One %or4er put out the5re %ith an e/tin#uisher. and another pulled

the ,ictim a%ay from the compartment %itha plastic ,acuum cleaner hose heparamedics responded in D minutesAlthou#h the ,ictim sur,i,ed the shoc4. he

died 2E hours later of $urns his deathcould ha,e $een pre,ented if the follo%in#precautions had $een ta4en>

ee safety report.ppt

Documents