Smart Energy Laboratory (SEL)
Computational Intelligence Applications (CIA) Laboratory

Department of Electrical Engineering
University of Washington

Electric Safety

Electric utilities place high priorities on providing their workers a safe environment for power line construction and maintenance. In addition, regulatory agencies such as the Occupational Safety and Health Administrations (OSHA) and the Institute of Electrical and Electronics Engineers (IEEE) provide fundamental rules to create a safe working environment . These rules are published in OSHA standards and the National Electrical Safety Code (NESC).

This course covers the foundations of personnel safety for utility work, including:

Transmission line maintenance and construction, including energized and de-energized works
Ground installations within the right-of-way of transmission lines; such as buildings, parking lots, and roadways
Stray voltage
Atmospheric discharges

Applicable OSHA standards, IEEE standards, and the NESC are discussed in conjunction with each topic. The course provides the engineering justifications (modeling and analysis) of the standards and safety codes.

Several real-world cases are presented, studied, and analyzed in this course. In addition, some of the tools used to analyze the worksite hazards and to test the safety procedures are discussed.

Participants will understand the foundations of electric safety. They will be able to identify hazards at the worksite, and will be able to design effective safety procedures at worksites.

Who should attend?

Utility engineers
Supervisors and workers of power line maintenance
Construction and maintenance personnel
Electric safety equipment manufacturing workers and engineers
Attorneys involved in electric safety issues

Topics Covered

Introduction to Electric Safety


Alternating currents
Three-phase systems
Power line conductors
Power line towers

Main Equipment in Power Systems

Transmission grids
Substations and switch yards
Protection, measurements and control equipment

Electromagnetic Coupling

Electromagnetic field
Induced voltage due to electrical field
Induced voltage due to magnetic field
Computation of induced voltage
Case studies

Human tolerance to Electricity

Biological effects of electricity
Safe limits of currents and voltages
Resistance of the human body

Grounds and grounding systems

Definition of grounds
Ground resistance of objects
Measuring the ground resistance of objects
Ground resistance of people

Hazards of Electricity

Step potential
Touch potential

Worksite Hazards

Identifying hazards
Isolation, insulation and grounding techniques
Concept of equipotential zone
Regulations and standards

De-energized work

De-energizing work site
Hazards of de-energized equipment
Definition of effective grounds
Main equipment used as temporary grounds
System grounding
Local grounding
Traveler ground
Creation of the equipotential zone
Protection of all workers at the worksite (on tower, inside the boom, and on the ground)
Real world case studies
Safety dilemma
Key standards

Live work

Basic safety concepts
Live work tools
Minimum approach distance
Exceptions for bare hand work
Aerial work
Case studies
Key standards and practices

Electric field under Power Lines

Hazards of induced voltage
Electric field strength
Industry rules on electric field strength
Minimum clearance rules
Case studies

Atmospheric Discharges

Characteristics of lightning
Traveling of lightning along power lines
Protection of system against lightning
Protection of personnel and equipment

Stray Voltage

Neutral versus ground
Grounding practice
Sources of stray voltage
Elimination of stray voltage