Electrical Safety 29 CFR 1910.332

Safety Training Presentations

Institute of Occupational Safety and Health

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/powerlines.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 NumbersTo 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/powerlines.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!