Electrical Hazards and Controls Module
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Questions and Answers

What is the highest temperature an electric arc can reach?

  • 5,000°C
  • 10,000°C
  • 20,000°C (correct)
  • 15,000°C

What is considered the primary cause of electrical fires?

  • Natural disasters
  • Excessive electrical usage
  • Faulty equipment design
  • Poor maintenance of electrical equipment (correct)

How far away can a person suffer burns from an arc flash?

  • 3 metres (correct)
  • 5 metres
  • 10 metres
  • 1 metre

Which of the following is NOT a factor that contributes to arcing intensity?

<p>Humidity in the environment (B)</p> Signup and view all the answers

What happens to metal during an extreme arc blast?

<p>It vaporizes (D)</p> Signup and view all the answers

Which of the following accurately describes a common cause of arcing?

<p>Damaged electrical terminations (B)</p> Signup and view all the answers

What type of setting is electrical fires most commonly associated with?

<p>Homes (D)</p> Signup and view all the answers

Overheating in older buildings is commonly caused by what factor?

<p>Uninspected alterations to wiring (D)</p> Signup and view all the answers

Which of the following human factors contributed to the incident involving the worker and the powerline?

<p>No signaler was used to alert workers of hazards. (A)</p> Signup and view all the answers

What was a significant factor leading to the apprentice's fatal injury?

<p>The panel was left energized while the apprentice worked. (D)</p> Signup and view all the answers

What type of electrical hazard is characterized by electricity entering the body to complete a circuit?

<p>Electrical shock (C)</p> Signup and view all the answers

Which scenario best illustrates 'direct contact' as a cause of electrical shock?

<p>A worker pulling a cable connected to an energized panel. (C)</p> Signup and view all the answers

What is a human factor that could have minimized risks during the first incident?

<p>Using a signaler to communicate hazards. (A)</p> Signup and view all the answers

Which of the following is NOT one of the three main types of electrical hazards?

<p>Static electricity (A)</p> Signup and view all the answers

In the context of electrical hazards, what does 'step or touch potential' refer to?

<p>The potential voltage difference between a person’s feet. (D)</p> Signup and view all the answers

What penalty did the company face for failing to ensure workplace safety regarding the apprentice's incident?

<p>$300,000 (B)</p> Signup and view all the answers

What is the primary reason electrical accidents are costly?

<p>They result in significant property damage, injuries, and fatalities. (A)</p> Signup and view all the answers

What is the injury-to-fatality ratio for electrical incidents compared to other occupational injuries?

<p>755 to 1 (B)</p> Signup and view all the answers

What is the most effective method for controlling electrical hazards?

<p>Elimination (D)</p> Signup and view all the answers

What factor is indicated as the major cause of electrical incidents?

<p>Human error or activity (D)</p> Signup and view all the answers

Which of the following describes over-fusing?

<p>Replacing a fuse with a higher ampacity fuse (D)</p> Signup and view all the answers

What does inherent safety primarily focus on?

<p>Reducing or eliminating hazards through design (A)</p> Signup and view all the answers

Which statement is true regarding the financial impact of electricity-related fires in Canada?

<p>304 deaths and 2,547 injuries were attributed to electrical fires. (A)</p> Signup and view all the answers

What should engineers prioritize according to their responsibilities concerning electrical hazards?

<p>Safety of the users of their products and designs. (C)</p> Signup and view all the answers

Which option exemplifies an administrative control for electrical hazards?

<p>Policies prohibiting the use of extension cords (C)</p> Signup and view all the answers

Which of the following statistics demonstrates the severity of electrical injuries?

<p>Every 15 non-critical injuries results in one fatality. (C)</p> Signup and view all the answers

What is an example of an engineering control related to electrical circuits?

<p>Using the correct fuse for a circuit (D)</p> Signup and view all the answers

What is an example of a situation that illustrates the potential hazards of electricity?

<p>A delivery is made using a boom truck at a construction site. (A)</p> Signup and view all the answers

Which principle is applied when substituting a hazardous power source with a less hazardous one?

<p>Substitution (C)</p> Signup and view all the answers

Which of the following is considered personal protective equipment?

<p>Insulated gloves (A)</p> Signup and view all the answers

What is the primary concern with the misuse of extension cords?

<p>They can cause overheating and potential fires (C)</p> Signup and view all the answers

Flashcards

Electrical Shock

When electricity enters the body, attempting to complete a circuit.

Direct Contact

Touching an energized conductor or surface.

Step or Touch Potential

Voltage difference between your feet when standing near an energized object.

Reverse Polarity

Hot and neutral wire connections at the receptacle are reversed.

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Arcing Incident

High-voltage discharge between two points.

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Electrical Fire

Fire ignited by electrical energy.

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Electrical Hazards

Risks associated with electricity that can cause harm.

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Hazard Assessment

Identifying and evaluating potential risks.

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Arcing

The discharge of electrical current through the air, creating a spark or arc that can cause ignition and burns.

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Hierarchy of Controls

A method for managing risks by implementing a series of controls, starting with the most effective measures and progressing to less effective ones.

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Elimination (Hierarchy of Controls)

The most effective control measure, which removes the hazard completely.

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Substitution (Hierarchy of Controls)

Replacing a hazardous substance or process with a safer alternative.

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Engineering Controls (Hierarchy of Controls)

Modifying equipment, processes, or work environments to reduce the risk of electrical hazards.

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Over-fusing

Replacing a lower ampacity fuse with one of higher ampacity. This is a dangerous practice often done by homeowners and building managers.

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Overheating of extension cords

Misusing extension cords, often in older buildings with limited outlets, can lead to overheating and potential fire hazards.

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Elimination

The most effective way to control hazards. It completely removes the danger, eliminating any risk of harm.

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Inherent Safety

Designing a system to inherently minimize hazards. This can be achieved through minimization, substitution, moderation, or simplification.

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Engineering Controls

Physical systems added to a process to prevent or mitigate hazards, like a safety guard on a machine.

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Administrative Controls

Rules and procedures implemented to guide safe work practices, like safety training or work permits.

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Personal Protective Equipment (PPE)

Equipment worn by workers to protect them from hazards. Examples include insulated gloves, boots, and protective clothing.

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What is arcing?

Arcing is the flow of electrical current through an insulating medium, often accompanied by light, heat, and sound. It occurs when an energized conductor comes into contact with a non-conductive material, creating a spark or arc.

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What is an arc blast?

An arc blast is the explosive expansion of air and metal caused by the extreme heat generated by an electrical arc. This occurs when the rapid heating of air and metal creates a forceful outward pressure.

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What is incident energy?

Incident energy is the amount of electrical current released during an arcing incident. It directly affects the severity of the arc flash and blast.

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What causes electrical fires?

Most electrical fires occur due to improper use, poor maintenance, or damaged electrical equipment. These incidents are caused by things like arcing, overheating, and faulty wiring, rather than faulty equipment design.

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What are some common causes of electrical fires?

Common causes of electrical fires include arcing and overheating. Arcing can happen with damaged wiring or faulty connections. Overheating can occur when too much electricity flows through wires that are too small, or when appliances or tools malfunction.

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How can electrical wiring alterations cause fires?

Altering electrical wiring in older buildings without proper inspection can lead to fires. These alterations may overload the existing wiring, making it more susceptible to overheating and causing fires.

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What are some ways to prevent arcing incidents?

Preventing arcing incidents involves taking steps to ensure electrical equipment is properly maintained, inspected regularly, and used correctly. This includes using appropriate tools, wearing protective gear, and avoiding overloading electrical systems.

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What are some of the dangers of arc flash?

Arc flash can cause severe burns, even at a considerable distance from the source. The extreme heat can ignite clothing and skin, and if inhaled, the hot vaporized metal can severely damage the respiratory system.

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Study Notes

Electrical Hazards and Controls

  • This module covers the dangers of electricity and control measures.
  • Upon completion, learners should be able to identify electrical dangers, describe different electrical hazards (shock, arcing, fires), and explain control hierarchies.

Learning Objectives

  • Remember: Identify dangers associated with electricity.
  • Understand: Describe electrical shock, arcing, and electrical fires.
  • Differentiate: Explain the hierarchy of controls for electrical hazards.

Cost of Electrical Accidents

  • Electrical accidents annually cost millions in property damage, injuries, and loss of life.
  • In one year, Canada experienced 53,589 electrical fires, 304 deaths, 2,547 injuries, and $1.49 billion in property damage.
  • Electricity-related accidents cost Ontario an average of $1.3 million annually.

Electrical Incidents (Examples)

  • Incident 1: A worker on a construction site received a fatal shock from an overhead powerline while working on a boom truck. This incident highlights the importance of safety zones, signalers, and preventing contact with powerlines.
  • Incident 2: An apprentice electrician was fatally injured while working on an energized electrical panel. Negligence in not de-energizing the panel and not ensuring appropriate PPE were worn led to the incident. Contributing factors were a lack of safety policy, insufficient supervision, and no hazard assessment.

Types of Electrical Hazards

  • Electrical Shock: Electricity entering the body, completes a circuit, potentially causing electrocution. Even small currents can be fatal. This can impact muscle strength, memory, and mental health.
  • Arcing Incidents: Electrical current flows through an insulating medium (air) causing a visible and audible spark. This can create intense heat and serious damage.
  • Electrical Fires: Fires often result from misused equipment or poor maintenance, particularly in homes. Arcing & overheating are typical culprits and can contribute to fatalities. These can be sudden or from gradual issues over time.

Electrical Shock (Direct Contact)

  • Direct contact with exposed energized conductors is a common cause of electrical shock.
  • Dangers exist at any voltage level.

Electrical Shock (Step and Touch Potential)

  • Step potential: Voltage difference between a person's feet when near a grounded conductor.
  • Touch potential: Voltage difference between an energized object and a person touching it.

Electrical Shock (Reverse Polarity)

  • Reversed polarity occurs when the wires in a receptacle are connected incorrectly.
  • Even simple household appliances can pose a significant shock hazard if not wired correctly.

Electrical Fires (Causes)

  • Arcing: Improper or damaged wiring terminations & conductors lead to sustained heat resulting in fires.
  • Overheating due to wiring alterations: Changes & additions to electrical systems (especially older ones) can overwhelm the circuit, causing overheating and increasing the risk of fires.
  • Over-fusing: Using higher-capacity fuses than the circuit is rated for allows too much current to flow, overheating conductors.
  • Overheating of Extension Cords: Inappropriate use of extension cords (e.g., daisy-chaining, improper routing) can overload the cords and cause dangerous overheating that can lead to fires.

Hierarchy of Controls

  • Elimination: Remove the hazard altogether.
  • Inherent Safety: Design safeguards into the product reducing risk factors.
  • Engineering Controls: Systems added to the process to prevent or mitigate a loss of containment; (like properly insulated tools).
  • Administrative Controls: Rules and procedures for how workers act around hazards.
  • Personal Protective Equipment (PPE): Equipment worn to protect workers from hazards.

Summary

  • Understanding electrical hazards, their causes, and preventive measures is crucial.
  • The Hierarchy of Controls provides a systematic approach.
  • Employee and public safety is the primary concern, even with low voltage appliances.
  • The principles within this module offer practical insight on working safely with electricity.

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Related Documents

Week 4 Electrical Hazards and Controls PDF

Description

This quiz explores the dangers associated with electricity and the measures to control these risks. Participants will learn to identify different electrical hazards, understand the implications of electrical accidents, and describe the hierarchy of control measures. Gain critical knowledge to promote safety in environments where electrical work is conducted.

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