Basic Electrical Safety
By Greg Bock
PLU Electrician
Why Bother?
 In 1997, over 12,000 people went to hospital
emergency rooms to be treated for
electrical shocks and burns.
 Hundreds of workers die every year from
electrical shock.
 The amount of current to power a 5-watt
lightbulb is enough to kill three people.
 One of your co-workers was injured last
year by electricity.
Voltage, Current, Resistance
 Voltage is the pressure or force that
carries the current.
 Current (amperage) is the amount of
electricity that flows.
 Resistance slows down the flow of
electricity.
Current Vs. Resistance
 Metals are good conductors of current
having very low resistance
 Rubber, ceramics, and wood are poor
conductors of current with very high
resistance.
 Materials with high resistance are often
called insulators.
 The human body can be a very good
conductor or a very poor conductor.
Factors Affecting the
Conductivity of the Human Body
 Condition of the skin: Is it wet, dry, greasy?
 Health of Individual
 Duration of Contact with Electricity
 Part of the Body contacted
See Do’s & Don’ts Handout
More Do’s & Don’ts
 Keep electrical equipment away from water
sources
 Use a C-rated fire extinguisher on
electrical fires and shut off power source
 Remove frayed or damaged equipment and
cords from service
 Remove plugs by pulling the plug; not the
cord.
See Extension Cord Handout
Grounding Electrical Equipment
 Grounding functions to conduct current
leaks to the earth or ground.
 A grounded cord is a 3-wire plug and
requires a 3-way receptacle.
 Double-insulated equipment does not
require grounding.
Electrical Shock Injury
Amps Milliamps
1
1000
Injury
Severe burns
0.1
Irregular heart beat
100
(requires medical defibrillation)
0.01
10
0.001 1
Cannot release grip
Threshold of sensation
See Electrical Shock Handout
Summary
 Even low
voltage electricity can cause
injury.
 Your body can be a good conductor of
electricity, especially when wet.
 Follow the Ground Rules of electricity.
 Do not use defective equipment.
Electrical Safety
Quiz