7/30/2019 safety electricity

1/20

7/30/2019 safety electricity

2/20

2

Electricity

The Dangers

About 5 workers areelectrocuted every week

Causes 12% of young

worker workplace deaths Takes very little

electricity to cause harm

Significant risk of causingfires

7/30/2019 safety electricity

3/20

3

Electricity How it Works

Electricity is the flow ofenergy from one place toanother

Requires a source of power:usually a generating station

A flow of electrons (current)travels through a conductor

Travels in a closed circuit

7/30/2019 safety electricity

4/20

Electrical Injuries

There are two main types of electrical injuries: Direct:

Electrocution or death due to electrical shock

Burns / Flash: When heat from a nearby electrical arc causes

thermal burns The temperature of an electrical arc can reach 2500-

5000o C

Electrical arcs

Indirect - Falls

7/30/2019 safety electricity

5/20

5

Electrical Shock

An electrical shock is received when electrical

current passes through the body.

You will get an electrical shock if a part of yourbody completes an electrical circuit by

Touching a live wire and an electrical ground, or

Touching a live wire and another wire at a

different voltage.

7/30/2019 safety electricity

6/20

6

Shock Severity

Severity of the shock depends on:

Path of current through thebody

Amount of current flowingthrough the body (amps)

Duration of the shockingcurrent through the body,

LOW VOLTAGE DOES NOTMEAN LOW HAZARD

7/30/2019 safety electricity

7/20

7

Dangers of Electrical Shock

Currents above 10 mA* canparalyze or freeze muscles.

Currents more than 75 mA cancause ineffective heartbeat --

death will occur in a few minutesunless a defibrillator is used

a small power drill uses 30 timesas much

* mA = milliampere = 1/1,000 of an ampere

Defibrillator in use

7/30/2019 safety electricity

8/20

8

Burns

Most common shock-relatedinjury

Occurs when you touchelectrical wiring or equipment

that is improperly used ormaintained

Typically occurs on hands

Very serious injury thatneeds immediate attention

7/30/2019 safety electricity

9/20

9

Falls

Electric shock can alsocause indirect injuries

Workers in elevatedlocations who experiencea shock may fall,resulting in serious injuryor death

7/30/2019 safety electricity

10/20

10

Electrical Hazards and How to

Control Them

Electrical accidents arecaused by a combination

of three factors:Unsafe equipment

and/or installation,

Workplaces made

unsafe by theenvironment, and

Unsafe work practices.

7/30/2019 safety electricity

11/20

11

Hazard Overloaded Circuits

Hazards may result from: Too many devices plugged

into a circuit, causing heatedwires and possibly a fire

Damaged tools overheating Lack of overcurrent

protection

Wire insulation melting, whichmay cause arcing and a fire in

the area where the overloadexists, even inside a wall

7/30/2019 safety electricity

12/20

12

Clues that Electrical Hazards Exist

Tripped circuit breakers orblown fuses

Warm tools, wires, cords,connections, or junctionboxes

Damaged insulation aroundwire or connection

7/30/2019 safety electricity

13/20

13

Safety-Related Work Practices

To protect workers from electrical shock:

Use barriers and guards to preventpassage through areas of exposedenergized equipment

Pre-plan work, post hazard warningsand use protective measures

Keep working spaces and walkwaysclear of cords

7/30/2019 safety electricity

14/20

14

Safety-Related Work Practices

Use special insulated tools

when working on fuses with

energized terminals

Dont use bad cords and

cables

Dont fasten extension cords

with staples, hang from nails,

or suspend by wire.

7/30/2019 safety electricity

15/20

15

Preventing Electrical Hazards -

Planning

Plan your work with others

Plan to avoid falls

Plan to lock-out and tag-out equipment

Remove jewelry

Avoid wet conditions andoverhead power lines

7/30/2019 safety electricity

16/20

16

Avoid Wet Conditions

If you touch a live wire or otherelectrical component while standingin even a small puddle of water youllget a shock.

Damaged insulation, equipment, or

tools can expose you to liveelectrical parts.

Improperly grounded metal switchplates & ceiling lights are especiallyhazardous in wet conditions.

Wet clothing, high humidity, andperspiration increase your chancesof being electrocuted.

7/30/2019 safety electricity

17/20

17

Grounding

Grounding creates a low-

resistance path from a tool

to the earth to disperse

unwanted current.

When a short or lightning

occurs, energy flows to the

ground, protecting you

from electrical shock,

injury and death.

7/30/2019 safety electricity

18/20

18

Preventing Electrical Hazards

Proper foot protection(not tennis shoes)

Rubber insulatinggloves, hoods, sleeves,matting, and blankets

Hard hat (insulated

nonconductive notuniform hat)

7/30/2019 safety electricity

19/20

19

Summary

Electrical equipment must be:

Listed and labeled (good quality)

Free from hazards

Used in right wayIf you use electrical tools you must be:

Protected from electrical shock

Provided necessary safety equipment

7/30/2019 safety electricity

20/20

20