Electrical Safety

Institute of Occupational Safety and Health

Safety Training Presentations

Electrical Safety
29 CFR 1910.332

FY-11 OSHA Susan Harwood
Grant Program
This material was produced under grant
number SH22297-SH1 from OSHA. It does
not necessarily reflect the views or policies of
the U.S. Department of Labor, nor does
mention of trade names, commercial products,
or organizations imply endorsement by the
U.S. Government.

Objectives: Participants will:
Interpret OSHA’s role and standards regarding
electrical safety / hazards
 Define the basic fundamentals of electricity
 Identify and recognize safety hazards
 Describe protection methods against electrical
hazards
 Analyze and discuss case studies


Introduction
An average of one worker is electrocuted
on the job every day
 There are four main types of electrical
injuries:


• Electrocution (death due to electrical shock)
• Electrical shock
• Burns
• Falls

OSHA Standards
Electrical safety-related work practice requirements
for general industry are detailed in Subpart S of 29
CFR
 Part 1910, in Sections 1910.331–1910.335. For
construction applications, electrical safety-related
work practice requirements are detailed in
Subpart K of 29 CFR Part 1926.416 to 1926.417.


Electric Basics
Electrical Flow:
Conductors – substances, such as metals- little resistance
to electricity
Insulators – substances, such as wood, rubber, glass, and
bakelite-high resistance to electricity
Current – the movement of electrical charge
Resistance – opposition to current flow
Voltage – a measure of electrical force
Grounding – a conductive connection to the earth which
acts as a protective measure

Electricity Basics


Water and electricity
• Pure water is a poor conductor
• Impurities can make water an insulator
• Salts
• Acid
• Solvents
• Working in a damp environment requires
preventive measures against electrical hazards

Electric Basics
What causes shocks?
Electricity travels in closed circuits,
usually through a conductor
Your body can be a conductor which may
mean an electrical shock!

Electrical Shock





Current passes through the body
Severity of the shock depends on:
• Path of current through the
body
• Amount of current flowing
through the body
• Length of time the body is in
the circuit
Low voltage does not mean low
hazard

Types of Electrical Shock
Injuries
Electrical burns
 Thermal contact burns
 Related hazards:
• Fire
• Equipment damage
• Fragmented metal
• Flammable gases, vapors or combustible dusts
• Arc or flash burns


ARC Flash: Live to Tell Video

“Freeze”
 Electrical

shock may cause the muscles
to contract
 This “freezing: effect” is dangerous

• Increases the length of exposure
 If

you witness a “freeze”

• Shut off the power
• Use a non-conductive object to knock the
person free of the contact

Severe Shock
A

severe shock requires medical help
immediately
 Unseen medical issues may be present, such
as:

• Internal Hemorrhages
• Destruction of tissues, nerves
or muscles

Static Electricity
 Created

when materials rub together
 Can cause shocks or even minor skin
burns
 Reduced or prevented by:

• Proper grounding
• Rubber matting
• Grounding wires, gloves, or shoes

Protection Against Electrical
Hazards
 Insulation

 Guarding

Grounding
 Most

electrical equipment is designed
with a grounding system
 Do not use equipment with damaged
grounding connectors
 Do not use adapters that interrupt the
grounding connection

Grounding Fault Circuit
Interrupters








GFCIs reduce the
likelihood of fatal shocks
Detect small amount of
earth current and
automatically switch off
the power
Used with extension cords
and portable tools
Fuses and circuit breakers
protect equipment, not
people

Circuit Protection
 Energize

or de-energize with appropriate
switches, breakers, etc.
 Do not energize or de-energize with
fuses, terminal lugs, or cable splice
connections
 If circuit protection device is tripped—
inspect

Protection from Power Lines









Maintain a safe distance to the lines High-voltage lines
Ground any equipment such as cranes that can become
energized
Lines must be de-energized and grounded by the owner or
operator of the lines
Guarding or insulating the lines help prevent accidental
contact
OSHA E-Tool:

•

http://www.osha.gov/SLTC/etools/construction/electrical_incidents/po
werlines.html

Protection for Machine Operators


Never tamper with electrical interlocks



Do not repair electrical components of your machine



Properly shut off machinery before working in the
point of operation



Obey warning signs and follow safe procedures

Protection Against Energized
Metal Parts


A break in an electric tool’s or machine’s
insulation can cause its metal parts to
become “hot”

•
•

Use “double insulated” tools
Equipment grounding conductor such as a three
prong plug

Unexpected Equipment Startup
 Proper

lockout/tagout procedures protect
from dangers of accidental startup of
electrical equipment

• 29 CFR1926.417, Lockout and Tagging of
Circuits

Lock Out Tag out: Lightning in a
Bottle Video

Portable Power Tools Safety
 Inspect

portable power tools
 Never use damaged equipment

• Tag it out of service
• Have it repaired or replaced
 Never

use portable power equipment in
wet or damp areas
 Stop using power tools if they become hot
or start sparking

Extension Cords





Inspect and check
for capacity
For temporary work only
Do not use as a rope
to pull or lift objects
Should not be fastened
with
staples or hung over
hooks

Electrical Cord Inspection





Deformed or mission pins
Damaged outer jacket or
insulation
Evidence of internal damage
If damaged, take out of
service until repaired

Other Electrical Hazards and
Protective Measures
Damaged insulation on wires
 Digging or trenching near buried lines
 Overloaded/exposed circuits
 Overheated appliances or tools
 Flammable materials


Safe Work Practices
 De-energize

electric equipment before
inspection or repair (Lock out Tag out)
 keeping electric tools properly maintained,
 Exercise caution when working near
energized lines
 Use the correct protective equipment

Guarding of Live Parts




Must guard live parts of electric equipment operating at
50 volts or more against accidental contact by:
• Approved cabinets/enclosures, or
• Location or permanent partitions making them
accessible only to qualified persons, or
• Elevation of 8 ft. or more above the floor or working
surface
Mark entrances to guarded locations with conspicuous
warning signs

Training
 Qualified

workers

• How to identify exposed energized parts
• How to safeguard or work on energized parts
 Unqualified

workers

• How electricity works
• Risks of working with energized equipment
• Tasks to be performed only by qualified
workers

OSHA Resources


OSHA has many helpful programs, including
assistance about safety and health programs, state
plans, workplace consultations, voluntary
protection programs, strategic partnerships,
training and education, and more

Summary
Electricity will try to reach ground even if it
means going through a person
 Even the “small” voltage from your home can
cause serious injury
 Always inspect power tools and cords and do
not use them if damaged
 Do not attempt to repair electrical equipment
unless trained and qualified


OSHA Contact Numbers
To report Unsafe Working Conditions, Safety
and Health Violations Contact OSHA @:
1-800-321-OSHA (6742) / TTY1-877-889-5627
To File a Complaint Form:
To file an OSHA-7 report online, see how to file
a complaint with OSHA (www.osha.gov)
For more information regarding your rights, see
Worker Rights

References










OSHA Publication 3075: Controlling Electrical Hazards
29 CFR1926.417, Lockout and Tagging of Circuits
OSHA E-Tool:
• http://www.osha.gov/SLTC/etools/construction/electrical_incidents/powe
rlines.html
LOTO Plus Expert Advisor
• http://www.osha-slc.gov/dts/osta/oshasoft/lotoplus.html
Self-Inspection Checklists
• http://www.osha-slc.gov/SLTC/smallbusiness/chklist.html#Electrical
Self-Inspection Checklists – Lockout/Tagout Procedures
• http://www.osha-slc.gov/SLTC/smallbusiness/chklist.html#Lockout

Institute of Occupational Safety and Health

Thank You

Let’s not meet again . . . by accident!