ELECTRIC SAFETY Practice and Standards By Mohamed El-Sharkawi

ELECTRIC SAFETY Practice and Standards By Mohamed El-Sharkawi

Contents:

 1. Fundamentals of Electricity

 2. Basic Components of an Electric Grid

 3. Physiological Effects of Electricity

 4. Ground Resistance

 5.General Hazards of Electricity

 6. Induced Voltage due to Electric Field

 7.Induced Voltage due to Magnetic Field

 8. De-Energized Line Work

 9. Live-Line Work

10. Arc Flash

11. Atmospheric Discharge

12. Stray and Contact Voltages

13. Electric Safety under Power Lines

14. Coupling between Power Lines and Pipelines, Railroads,

and Telecommunication Cables.

Preface:

Electricity.is.one.of.the.best.forms.of.energy.known.to.man;.it.is.clean,.readily.available,.quiet,.and.highly.reliable..Equipment.powered.by.electricity.is.pollution.free.and.is.more.compact.than.those.powered.by.other.forms.of.energy.such.as.gas.or.oil..Because.of.the.overwhelming.advantages.of.electricity,.it.has.now.become.widely.available.by.just.the.flip.of.a.switch.Since.the.early.days.of.the.electrical.revolution,.electricity.was.recognized.as.hazardous.to.humans.and.animals..Today,.in.spite.of.the.safety.products.available.in.the.market,.more.than.1000.people.are.killed.every.year.in.the.

United.States.alone.due.to.electric.shocks.and.several.thousands.more.are.disabled.or.injured.

Performing. maintenance. work. on. an. electric. grid. is. a. daring. job. that.demands. a. high. degree. of. skill. and. attention.. It. is. therefore. handled. by.highly.trained.linemen.who.deserve.great.appreciation.for.their.dedication.to.maintain.our.light.evn.under.harsh.and.hazardous.conditions.To.protect.the.public.and.workers.from.the.hazards.of.electricity,.several.regulations. and. standards. have. been. developed. to. address. every. electric.

safety.issue.known.to.man.so.far..On.December.29,.1970,.President.Nixon.signed.into.law.the.Occuponal.Safety.and.Health.Act..The.purpose.of.the.legislation.was.to.“assure.so.far.as.possible.every.working.man.and.woman.

in.the.Nation.safe.and.healthful.working.conditions.”.Before.this.legislation.was.implemented,.about.15,000.job-related.fatalities.(not.all.related.to.electricity).were.reported.every.year.in.addition.to.2.5.million.disabilities.and.300,000.cases.of.illnesses.To.administer.the.act,.the.secretary.of.labor.created.a.new.division.in.the.Labor.Department.called.the.Occupational.Safety.and.Health.Administration.(OSHA)..Its.mission.was.to.assure.the.safety.and.health.of.America’s.workers.by.developing.and.enfrcing.standards,.providing.safety.training,.and.improving. safety. and. health. in. the. workplace.. On.May. 29,. 1971,. the.first.group.of.standards.was.adopted.to.provide.baseline.for.safety.and.health.protection.in.American.workplaces.Today,.OSHA.and.its.state.partners.have.over.2000.inspectors.and.more.than.200.offices.throughout.the.United.States..In.addition,.it.uses.the.service.of.engineers,.scientists,.standards.writers,.attorneys,.and.other.technical.and. support.personnel. OSHA’s.Code.of.Federal.Regulation.(CFR).is.a.set.of.standards.that.deals. with. several. job-related. issues. such. as. electric,. mechanical,. and. chemical. safety..The.electric.safety.code.can.be.found.in.OSHA’s.standard.29.CFR.1910. in.sections.such.as.1910-137,.1910-269,.and.1910-302.

The. Institute. of. Electrical. and. Electronic. Engineers. (IEEE). has. sev

eral. working. groups. and. standard. committees. devoted. to. electric. safety..

This organization.has.an.international.outlook,.and.its.work.is.the.collective.

judgment.of.its.members..It.is.therefore.considered.the.source.of.all.stan

dards.worldwide..As.a.matter.of.fact,.OSHA.rules,.in.most.cases,.are.direct.

extractions.from.IEEE.standards.Based.on.my.experience.as.a.safety.consultant.and.expert.witness,.I.find.that.electric.safety.at.worksites.is.often.left.to.field.workers.whose.experience.is.transferred.from.one.generation.to.the.next..Furthermore,.the.safety.procedures. are. often. based. on. having. workers. memorize. a. set. of. rules..Logical. explanation. of. these. rules. may. not. be. provided. to. field. workers.or. be. fully. understood. by. them.. When. a. rule. is. forgotten. or. incorrectly.extrapolated,.hazardous.conditions.occur.at.the.worksite..To.address.this.problem,.electrial.engineers.must.acquire.more.knowledge.in.the.area.of.electric.safety.and.must.be.able.to.enhance.th.training.modality.of.field.workers.and.to.communicate.instructions.clearly.to.them..This.cognitive.

learning. will. certainly. improve. the. safety. at. worksites.. However,. unfor

tunately,. most. power. engineers. are. not. familiar. with. the. electric. safety.

practices.governing.site.works.