Basic Electrical Safety
By Greg Bock
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
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
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
Materials with high resistance are often
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
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
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
Electrical Shock Injury
Amps Milliamps Injury
1 1000 Severe burns
0.1 100 Irregular heart beat
(requires medical defibrillation)
0.01 10 Cannot release grip
0.001 1 Threshold of sensation
See Electrical Shock Handout
Even low voltage electricity can cause
Your body can be a good conductor of
electricity, especially when wet.
Follow the Ground Rules of electricity.
Do not use defective equipment.