Technical Program Abstracts
The ESW 2024 Technical Program will incorporate these papers
A Tale of Two Standards
The plot of Charles Dickens famous novel, A Tale of Two Cities, hinges on the resemblance between the two main characters, Sydney Carton and Charles Darnay. Yet, in other ways the two individuals are very different.
The two North American workplace electrical safety standards, NFPA 70E and CSA Z462, very much resemble each other, yet in other ways they are very different.
This paper will explore the similarities, the differences, and the origins of each. It will discuss why both standards should be consulted by organizations wishing to optimize electrical safety performance.
Analysis of Live Work Accidents in Overhead Power Lines and Substations Between 2010-2022
Eduardo Ramirez-Bettoni, Marcia Eblen, Balint Nemeth
Live working is a favored methodology by transmission and distribution system operators in order to carry out maintenance activities without the de-energization of the equipment working on. The accidents statistics shows that live working is a safer technique, than working on de-energized system elements, because using of live-line working tools, personal protective equipment (PPE) and well-regulated workflow guarantee the safe intervention on the energized system elements. Contrarily, working on de-energized network parts, the accidental switch back poses high risk, as there is no PPE used against the appearing potential. On the other hand, accidents during live working occur every year all over the world, e.g.: due to the usage of damaged live-working tools. The aim of this article is to summarize the accidental statics since 2010, on which based the root cause of the hazards can be explored and categorized. Based on the statistical analysis of the accidents, preventive measures for the safer working are also discussed.
Application of DC AF Incident Energy Reference Boundary Area Plots in TCCs Considering Input Parameter Variability
Albert Marroquin, Raghu Veeraraghavan, Walter Gonzalez, and Marcin Ruta
This work introduces the concept of dc C-areas in time-current characteristic plots (TCCs) for establishing a reference of dc arc-flash (dc AF) incident energy (IE) during the protection and coordination study. The concept of C-areas was introduced to the electrical safety community in  and this work expands on C-area application for dc equipment. dc C-area reference plots allow protection engineers to select overcurrent protective device settings in TCCs while keeping track of the allowable incident energy. This work explains the theory and derivation of the dc C-areas, the impact of the input parameter variability, and provides a detailed explanation of the data collection challenges for performing a dc arc-flash incident energy analysis. Gaps between conductors, enclosure dimensions, dc short-circuit currents are perhaps more variable in dc than in ac equipment.
This work presents examples of the difficulty to determine the input parameters to use in a dc AF study and explains how dc C-areas can aid in the process. The dc C-area methods introduced in this paper are based on industry accepted dc arc-flash calculation equations, yet novel concepts in dc C-areas such as arc elongation and conductor erosion effects are discussed along with their effects. Application examples of C-area use in protection and coordination studies for Battery energy storage (BESS) and photovoltaic (PV) systems are included. The protection and coordination device setting selections made by means of dc C-areas are then compared to actual dc arc-flash incident energy calculations performed in a commercially available power system analysis software to validate the methodology.
Arc Flash Analysis for Antarctica Research Facilities
Elizabeth Hames, Alex Radulescu, and Raymond Gonell
The National Science Foundation (NSF) requested a coordination and arc flash analysis for two of its Antarctica research facility stations. The location of these stations presented unique problems that are not typically addressed in arc flash analyses.
The study required sending engineers to Antarctica to collect data for the analysis. Travel to the stations requires substantial time and costs for medical screening, equipment preparation, and the travel itself. The efficiency and completeness of data collection is vital due to the difficulty in returning and the restricted travel time. A method for data collection was developed to improve efficiency, precision, and quality of data.
The ambient temperatures and elevation in Antarctica are extreme, with temperatures reaching -73C and elevations at 9300 feet above sea level at the South Pole station. This study evaluates the impact of these environmental factors on arc flash energy and fault clearing times. Findings reveal that high altitude and low temperature can significantly increase arc flash incident energy.
This paper discusses the data collection method, adjustments for extreme ambient conditions, and preliminary results for the Antarctica arc flash study. The findings of this study provide valuable insights into the analysis of electrical systems in extreme environments and methods for minimizing risks associated with arc flash incidents under these conditions.
Arc Flash in Single Phase Power Distribution
John F. Wade and Terry W. Becker
NFPA 70E and CSA Z462 require a Qualified Person to document a work task’s arc flash risk assessment. Single phase electrical equipment would currently be identified as not able to sustain an abnormal arcing fault. IEEE 1584 – 2018 documents the standard method for calculating arc flash incident energy and the arc flash boundary, at an assumed working distance, for 208VAC to 15kVAC three-phase electrical equipment. While IEEE 1584 covers three-phase equipment in detail, the 2002 and 2018 editions excluded single-phase systems. Single-phase and split phase AC power are the standard for residential and light commercial distribution around the world, and single-phase electrical equipment is common in industry.
This paper describes single-phase arc flash experimental work conducted in 2020 in support of a doctoral dissertation. The principal investigator’s goal was to improve confidence in equipment labeling practices in support of his role as an industrial plant chief electrical engineer. The experimental hypothesis was: there would be some available system power below which arc flash incident energy would be low (less than 1.0 cal/cm2). This threshold correlated with phase-to-phase voltage near 434VAC in the one configuration tested. Repeated test groups at greater than 434V sustained the conclusion that such configurations can develop higher levels of incident energy and arc blast pressure even when the source is single-phase.
Arc Flash Risk Assessment – View from EU Projects Approach
In this paper, I will summarize typical problems I see in EU based on arc flash study projects like: Legislation across different EU countries, Individual companies’ approach. (US and EU based), Personal view regarding common misconceptions in EU about arc flash. Practical, and IEC, EN and other standard’s correlations with arc flash.
Practicality of a copy-paste approach NFPA70E to EU? Is there a better way? A comparison between IEEE1584 and DGUV 203-077 for arc flash calculation and the applicability of both methods. This EU perspective will be based on a project’s dual arc flash study.
Some issues are similar between the EU and the US, but sometimes, people struggle in the EU with arc flash concepts. This is partly because of education and awareness issues, missing technical knowledge, and ignorance of legislation and standards across different countries.
In the author’s opinion, a lot of things are not aligned together, especially around technical knowledge, electrical safety awareness and law requirements in EU. These discussions will help to link worldwide professionals, centers of excellence in industry, engineering, government, and medicine. It is felt this paper will assist with changing and advancing the electrical safety culture to enable sustainable improvements in the prevention of electrical accidents and injuries from a more global perspective.
Are We Safe from Lightning Inside Buildings? – A Study of Lightning Deaths Inside Residences in Brazil in 2022
Danilo Ferreira de Souza, Milton Shigihara, Helio Eiji Sueia
Death caused by lightning is infrequent compared with other accidents of electrical origin (fires and electrical shock at industrial frequencies 50 or 60 Hz). Deaths by lightning inside buildings are rare. However, a substantial increase in cases of lightning electric shock with victims using electronic equipment, particularly cell phones, has been registered in Brazil. Thus, this paper analyses three cases of lightning strike deaths with victims using cell phones connected to the electrical network during the accident.
Case Studies in Battery Risk Assessment
David Rosewater and Curtis Ashton
Recent advances in battery risk assessment methodology can be difficult to understand and apply. This paper presents a series of example risk assessments on real battery systems of different sizes and chemistries. We walk through work planning and control process for energized work on batteries from the initial work order to project completion. We elaborate on how different engineering controls, such as a ground fault detector and indicator, impact battery risk assessment and what to do when you don’t know if they are functioning correctly. We present case studies in several types of battery systems, including lead acid, lithium ion, and vanadium redox. The paper concludes with an assessment of training, policy, and code shortfalls that may have contributed to past accidents.
Communication – Number One Electrical Safety Issue
Whenever something goes wrong on an electrical project, the first thing that is always blamed is a failure in communication. Someone on the project team just did not get the message as to how the job was to be done. There was a very famous movie line involving a prison Sheriff and a Prisoner who refused to follow instructions and was always trying to escape. The Sherriff makes the comment – “What we have here is a failure to communicate.”
This paper will examine how difficult it can be to communicate on what seems to be a relatively easy task. As part of an electrical safety class, a quiz must be given to see if the student learned the information. The hardest part of the quiz is the student marking the scores on the paper where the office staff can find them and record them in the records.
A controlled experiment was conducted over a two-year period at various companies across the entire United States on how to mark the scores on the quiz. There were three methods tried and the paper will examine the results of each method and what that means for electrical safety when performing a job.
Dismiss Your Fears: A Guide to Writing and Presenting a Paper at the IEEE Electrical Safety Workshop
David B. Durocher
The 2023 IEEE Industry Applications Society (IAS) Electrical Safety Workshop (ESW) held in Reno, Nevada was yet one more remarkable success. Over 450 people focused on advancing the electrical safety culture registered to attend the event, including over 200 first-time attendees. Often heralded as the most diverse gathering of all IAS sponsored conferences, the Workshop included engineers, electricians and safety professionals from a broad range of industries, government and academics during the four-day gathering focused on electrical safety. A genuine passion for keeping people safe is obvious and evident in ESW technical presentations. Sharing updates on industry standards, bettering best practices, and lessons learned from near-miss events, leaves some attendees feeling compelled and inspired to share their personal safety experiences at a future Workshop.
Which of the 450 plus registered electrical safety enthusiasts who attend the annual ESW are qualified to submit a paper/presentation idea for a future Workshop? Any safety enthusiast who is inspired to do so! The purpose of this article is to offer a “how-to guide” for perspective authors to act on their inspiration, offering next steps to rise-up and serve as an ESW author at an upcoming conference.
Does NFPA 70/NEC and NFPA 70E Add Electrical Safety Value to Electric Utilities?
George T. Cole
For decades, two nationally recognized documents related to safe electrical design and installations and safe electrical work practices have essentially been ignored by many electric utilities.
Under the “Not Covered” scope of the National Electrical Code (NEC), also known as National Fire Protection Association (NFPA) 70 and NFPA 70E, Standard for Electrical Safety in the Workplace, we find an interesting exclusion buried in a subsection. In article 90.2(B)(5)(b) of the NEC and article 90.2(B)(4)(c) of 70E, we’re told “This standard does not cover safety-related work practices for the following: Are on property owned or leased by the electric utility for the purpose of communications, metering, generation, control, transformation, transmission or distribution of electric energy.”
While transmission and distribution systems may be distinct enough to warrant this exclusion, but can the same be said of electric power generation plants? Apart from the plant’s switchyard interconnection to the grid, the generator and the generator step up transformers, the remaining electrical equipment is identical to large industrial plants.
This paper will challenge a long-established misunderstanding that 70E and NEC don’t provide much electrical safety value to generation. Consequently, many power plant design engineers and safety professional are either ignorant of them or intentionally choose to ignore their value.
Electric Shock Incident Investigation Utilizing In-depth Electrical Exposure Reconstruction Techniques
Paul W Brazis, Jr., Leslie Peterson, and Hai Jiang
UL is a global testing and certification laboratory which as part of its operations conducts potentially hazardous electrical testing. In addition to obligatory safety compliance and OSHA reporting, UL has implemented additional incident response measures beyond what is required. These include voluntary reporting tools, reporting of near-miss incidents so that lessons can be learned from them, and a comprehensive analysis of each incident. This analysis includes identifying factors contributing to the incident as well as an electropathology analysis to understand the shock exposure to the victim as well as understanding what the potential result could have been if conditions were modified slightly. This analysis is conducted with the message that the goal is to gather lessons learned from the incident rather than seeking to determine blame.
This presentation outlines the process used by our EHS and R&D organizations after an electrical incident and two case studies to demonstrate the process. The ultimate goal of this approach is to identify trends across incidents and to create a feedback loop where lessons learned improve overall laboratory safety, with an aspiration to drive total electrical incidents towards zero over time.
Electric Vehicle Charging Safety – State of Art, Best Practices and Regulatory Aspects
Boosted by the climate action and price development of lithium-ion batteries, the number of electric vehicles is breaking records globally. This raises new safety issues for both automotive and electrification sectors. This paper focuses on safety and accessibility issues for electric vehicle charging infrastructure and best practices in designing charging sites.
The regular AC charging infrastructure is protected with protective earthing and GFCI with DC fault current protection, which currently provides an adequate level of protection. The DC fast chargers have built-in protective devices. Electrical accidents with charging infrastructure are rare, as the maintenance
The fire safety of the charging site is reviewed and approaches for handling electric vehicle fires in different countries are reviewed. Additionally, as an EV charging is exceptionally high, long lasting, and repetitive electrical load in comparison to regular household electrical loads, the safety issues in electric vehicle home charging are discussed, as well as cybersecurity and accessibility issues.
Electrical Equipment Task Based Risk Assessment – Using the HRN Method
This paper describes how a commonly used machine risk assessment methodology has been ‘slightly’ modified for use to evaluate common tasks associated with electrical equipment. This method can be used to provide a hazard rating number (HRN) for a specific electrical task performed on a specific piece of electrical equipment. The author has applied this methodology to an entire site’s electrical distribution system from the incoming utility, on site power distribution, 24kV to 480V or 2400V substations, switchgear, and motor control centers. The method considers the effectiveness of the site’s maintenance program, health and age of the equipment, active / passive controls, engineering controls, use of procedures, and arc flash energies. This paper will present specific examples for the ‘as-found’ condition and then explore how mitigation methods affect the HRN score. The results are used for decision making on how to spend capital to improve safety and prevent electrical injuries.
Electrical Fatal Accident by Electric Shock and Epidemiology In 2018
When a human body touches a charged object of the electrical installation, the electrical shock accident occurs by an electrical current. We have to eliminate electrical fatal accidents by the electrical shock because many fatal accidents by the shock occur in U.S.A and Japan etc.
A construction of skyscraper and an old building demolition are performed and a construction work and an electrical construction work increase. When such construction work and electrical construction work increase, there is a possibility that electrical shock accidents increase.
The case study of the electrical fatal accident by the electric shock is needed because we eliminate the fatal accident by the shock. We continue the case study of the electrical fatal accident and need to propose the preventive measures of the electrical fatal accident.
We performed the case study of the 13 electrical fatal accidents by the electric shock in 2018 of Japan. The electrical fatal accident of 38% occurs by the touch with transmission and distribution lines, etc. The electrical fatal accident of 31% occurs by power equipment. The results will be helpful to eliminate the electrical fatal accident by the electric shock.
Electrical Safety Leading Indicators
Lagging indicators are helpful but leading indicators are more important and what drives results. As an example, if the goal is losing weight, measuring the weight (lagging indicator) everyday will tell you if you are losing weight or not, but it does not contribute to your goal of losing weight. Effective leading indicators are the number of workouts you have done or the quality of the food you eat. These measures and indicators will drive results. The same way for the electrical safety indicator – recording number of incidents by itself does not reduce the number of incidents. Important leading indicators like implementation of electrical safety program or specifically wearing the proper PPE as required are the ones that will drive the reduction of incident. The objective of this paper is to discuss in details leading indicators for electrical safety that will drive down electrical related injury.
Equipotential Zone Grounding and Bonding at 4.16/13.8 Switchgear and Loads – Why’s/Challenges/How’s?
Mike Doherty, David Wallis, and Marcia Eblen
This paper will focus on the potential hazards when providing equipotential zone grounding and bonding systems for workplace scenarios involving medium voltage equipment such as those addressed by the National Electrical Code (NEC), ASTM F855, and the Occupational Safety and Health Administration (OSHA) and other jurisdictions having authority.
Equipotential zone (EPZ) electrical grounding and bonding play an important role in ensuring worker safety in medium voltage switchgear installations, by reducing the risk of electrocution and arc flash injury from hazardous levels of voltage rise. However, improperly applied temporary protective grounds can increase electrical hazards under certain conditions.
Equipotential zone electrical grounding and bonding systems are crucial to ensuring the safety of personnel in medium voltage switchgear installations by ensuring that any electrical fault current is quickly and safely redirected to ground. It requires careful design, installation, testing, and maintenance to ensure that it is functioning properly and providing adequate protection.
Best practices for temporary protective grounds (TPGs) and grounding truck set ups for work on electrical loads remote from the switchgear will be discussed. The importance of overcurrent protective devices (OCPDs) will be emphasized. LO/TO best practices, as rigorous and robust, will be stressed.
Hazards will be identified, the potential severity and damage to health will be estimated and hierarchy of risk controls will be as per NFPA 70E and CSA Z462 and other applicable standards. The paper will cover power generation, industrial and the construction electrical sectors.
Evaluating Substations to the 2023 NFPA 70B Standard
Austin M. Johnson, Scott T. Brady, Paul B. Sullivan, and Sharon G. Mullen
With the 2023 revision of NFPA 70B from a recommended practice to a standard, there is a need for examples and best practices on how to evaluate equipment maintenance programs to the NFPA 70B requirements. Processes for evaluating both new and existing equipment should be done in a pragmatic and unbiased approach.
The authors are partnering to review the electrical maintenance program for both a newer substation and an older substation to the 2023 revision of NFPA 70B. The process will review and compare the existing electrical maintenance plan to the requirements in NFPA 70B along with the original equipment manufacturer’s recommendations and highlighting and addressing gaps discovered. The partnership will also provide a chance to develop and implement a method to evaluate the equipment condition in an unbiased manner. This paper will share the findings from the evaluation in a lessons learned format for the IEEE community.
How Variability in Arc Ratings Is Stifling Innovation in Development of Arc Rated Clothing
Aasim Atiq and James Cliver
Arc-flash testing has given end-users access to increasingly thinner and lighter clothing and while meeting protection needs. However, at the same time, manufacturers have also faced challenges in maintaining the performance characteristics of products. In this case study we walk through the design process to explain how new products are taken from the concept to commercialization and illustrate examples on how variability in arc ratings creates imbalance in the market that impacts commercial feasibility of products. We will also share test results on sample garments to compare arc ratings of fabrics with response characteristics and design integrity of garments.
Is Racking In or Out a Low or High Voltage Power Circuit Breaker Simple?
During field implementation of Electrical Safety Programs and while performing External Electrical Safety Audits it was discovered that Qualified Persons (e.g. Qualified Electrical Workers) were not effectively trained on how to rack out a low voltage power circuit breaker or how to complete emergency racking out of a remotely racked power circuit breaker when the onboard racking system fails. Is racking out a low or high voltage power circuit breaker simple?
Depending on the manufacturer low or high voltage power circuit breakers may have unique interlocks, it may not just be as simple as inserting the racking tool and racking the power circuit out.
In that last decade manufacturer’s have brought innovation to industry with substitution creating an on board racking system for high voltage power circuit breakers rather than having manual racking occurring, elimination of exposure. What happens if this automated system fails, has the Qualified Person been effectively trained to manual rack, is the manual emergency racking simple?
This case history will provide insight confirming that racking out low or high voltage power circuit breakers is not necessarily intuitive and simple.
Likelihood of an Unlikely Incident
H. Landis “Lanny” Floyd
Accurate identification of hazards, assessment of risk and evaluation of risk controls are essential to moving beyond simple compliance with electrical safety regulations and standards. If hazard identification and risk assessment are not done properly, or at all, the proper and most effective risk controls will often not be applied. This is especially true for electrical incidents as the very low frequency of electrical injuries, compared to all occupational injuries, can blind organizations and individuals to the potential for serious or fatal electrical injuries. Risk can be underestimated, and the effectiveness of controls overestimated. Risk determination is a function of incident consequences and the likelihood of ______. “An incident” may not be the right words to fill in the blank. This paper reviews risk analysis and assessment literature to find the keyword to go into the blank, which will lay the foundation for selecting the most effective risk controls to prevent serious injury and fatality.
Making the Business Case for Electrical Safety in the Workplace
How do companies justify the cost of keeping electrical industrial systems safe? As an industry, we have made the delivery of electricity so safe that people tend to forget how dangerous it really is. Those of us who oversee electrical systems understand the hazards and protocols needed to keep both the end users and the personnel responsible for working on and maintaining the systems safe. But safety programs cost money and convincing management that safety programs are worth the cost can be a difficult task. Management may have misconceptions on the national standards requirements to keep electrical systems safe. Some perceived compliance issues are getting arc flash labels on everything is enough or purchasing PPE at 40 cal/cm2 and having that for all electrical work activities rather than an arc flash analysis. The necessity of establishing a program to maintain the equipment to the level that ensures those arc flash labels are accurate is not understood and therefore overlooked. Attitudes such as, “We’ve never had a serious electrical accident on our site,” contribute to an attitude of complacency that greatly increases the probability of an electrical incident occurring.
How do we get management’s attention and focus on the importance of establishing and supporting a comprehensive electrical safety program? This paper focuses on some strategies that can be used to develop the business case for electrical safety and educate management as to why it is in their best interest to support a comprehensive electrical safety program.
Modeling the Conversion of Electrical Energy to Acoustic Energy for Arcs and Applications for the Selection of PPE
Lloyd B. Gordon and Joseph Bradley III
Electric shock hazards have been addressed for 50 years, arc flash hazards for about 40 years,
and acoustic hazards for about 30 years. There are two distinctly different types of acoustic injury,
from sonic pressure waves and from supersonic blast waves. The type of acoustic hazard is a
function of the nature of the release of energy by the arc source.
This paper will cover acoustic hazards of arcs of batteries, low-voltage power, medium-voltage
power, super capacitors and capacitors. The models currently in use to predict the hazard, and
the types of injury from sonic and supersonic acoustic waves will be presented. The weaknesses
and gaps in what is known, and how the acoustic hazard is being modeled will be presented.
Modifying the DC Arc Flash Max Power Formula to Give More Realistic Predictions of Maximum Arc Flash Energy
The maximum power formula for calculating DC arc flash incident energy has been in NFPA 70E since 2012; however, repeated testing by multiple companies over the years has shown that it overestimates arc flash energy by a factor of at least 2-10, especially at lower voltages (such as nominal 48, 125, or 250 VDC). This paper analyzes the actual measured arc flash energy from over 100 different tests at various voltages and proposes modifications to the arc sustaining time in the maximum power equation found in Annex D.5 of NFPA 70E.
NFPA 70E Proposed DC Arc Flash Updated Guidance
William Cantor, Lloyd Gordon, and Sai Marri
The Standard for Electrical Safety in the Workplace (NFPA 70E) is the industry standard for electrical worker safety. In 2012 DC arc flash guidance was added to the document. There have been updates since then, but most arc flash calculations still rely on the maximum power method that has been unchanged since 2012. The maximum power method is extremely conservative, and in most cases, grossly overestimates the true hazard. Additionally, some users are multiplying the result from the maximum power method by three for anything in a cabinet even though this specific multiplier has been removed from the standard in the last few cycles. This results in an even more conservative calculation.
The main issue with updating the guidance has been the lack of test data for dc arc flash. AC arc flash has been well characterized by comprehensive testing and modelling resulting in very specific guidance in IEEE 1584. However, over the few several years, several organizations have conducted dc arc flash testing and much of this has been reported. In addition, there have been efforts, including by a co-author, to better characterize the risk through modelling using this test data.
This paper will document proposed changes to the next revision of NPFA 70E which the authors plan on turning into public inputs which will be submitted in the summer of 2024 for the 2027 revision. These changes will improve overall worker safety and provide more rational guidance.
Role Specific Approaches for Electrical Incident Investigation
Zarheer Jooma and Jay Prigmore
Incident investigations have different meanings, goals and priorities to different individuals in the workplace. Engineering personnel may be concerned with the equipment failure mode while safety personnel may be interested in the impact to workers and legal personnel may be interested in possible litigation. Often the department leading the investigation focuses on their discipline without taking a wider view. This narrow field of view may omit investigating causal factors and fail to identify systemic weaknesses. Such weaknesses can go undetected for years until finally manifesting in loss.
This paper explores two main types of investigations in industry – incidents resulting in equipment damage and incidents resulting in harm to workers. Case studies will be used to explore how the results of the investigation are influenced by the focus of the investigators. After establishing this foundation, the paper explains techniques to ensure that all investigations address all systemic gaps in a single investigation, converge findings, include important role players, and ensure that omissions are reduced or eliminated. The authors aim at presenting investigation best practices based on benchmark handbooks and consensus standards. The paper aims to improve the effectiveness of electrical incident investigations and advance the electrical safety culture through findings that lead to improved equipment designs, safety systems, and safe work practices.
Preventing Electric Shock by Proper Grounding and Bonding of Outdoor Separately Derived Systems
Mario Orellana and Joseph Mercede
Explaining the proper configuration for grounding and bonding of separately derived systems that are installed outdoors, separate from the building or structure. There are two different configurations that meet the requirements of the NEC. The first option is to install a System Bonding Jumper at both the separately derived system and at the first disconnect means. The feeder between the separately derived system and the first disconnect means must be installed in a non-ferrous raceway and not contain a Supply Side Jumper, thus eliminating any parallel paths for fault current. The second option is to install a single System Bonding Jumper at the separately derived source and include a Supply Side Bonding Jumper with the feeder. The Supply Side Bonding Jumper is terminated at the first disconnect means and provides the only path for fault current.
We’ve identified a recurring problem of incorrect configuration of these two methods in designs and installations at our facility that warrants additional explanation with detailed visual aids. Improper configuration can lead to hazards to personnel and equipment as well as system instability.
Protective Wall (Arc Cube Installation)
Kirk Gray and Jean Brouillette
During a routine start-up of a 300-MW generator, at a power plant, the excitation transformer supplying the excitation system for this generator suffered considerable damage due to a polyphase short circuit on the high voltage (HV) side. At time of the incident, the generator was not yet connected to the transport network, more precisely, the generator circuit breaker was open. An investigation and analysis, involving experts, was enabled to establish the cause and sequence of the incident. The first step to ensure the security of the personnel, and to establish a restricted boundary around the other transformers found in this power plant. The second step was to install a Kevlar protective screens system around the transformers to reduce the size of the boundary’s. The methodology on the calculations for the boundary and Kevlar protective screens system will be explained.
The Alarming Safety Knowledge Gap Among New Electrical Workers
When workers in the electrical trade go through schooling and on-the-job apprenticeships, it is all too common for electrical safety to be an afterthought. When workers are hired to perform electrical tasks, often times there’s minimal electrical safety training provided, if any. How does this impact the number of workers being injured or killed who are new to the job? It’s resulting in an alarming number of injuries within the first few years on the job, most of which go unreported due to fear of repercussions. This trend continues for many who, over the course of their careers, have never received the education they so desperately need to work safely and over time even influence newer workers to be unsafe, whether they realize it or not. This has been an issue for 50+ years. Advancements have been made for electrical safety in the workplace, so why haven’t the same advancements been made in the schooling of our electrical workers?
In this paper, attention will be brought to the troubling disconnect between expectations for electrical workers to perform their tasks safely by following the NFPA 70E, and the lack of curriculum in trade schools covering safe work practices. It will also provide some insight into efforts to bridge this knowledge gap, starting with certain local trade schools of the author.
The Challenges of Safe Troubleshooting Work
Troubleshooting work presents electrical and other workers with a challenging combination of physical hazards, working conditions, and time pressure, which can lead to unwanted outcomes if not carefully managed. Summaries of several injury or close-call incidents that occurred while performing troubleshooting work will be presented, identifying organizational weaknesses and error precursors that contributed to each incident.
The primary challenges include:
- Deranged equipment. Equipment that needs troubleshooting is not in a normal operating condition. Actions that are safe when the equipment is in a normal state may not be safe in the deranged state.
- Work planning and control. The steps taken in troubleshooting are most often determined by the results of the immediately previous diagnostic test, making effective work planning challenging.
- Multiple types of hazards: Most equipment will present a troubleshooting worker with several types of hazards, including hazardous energy as defined in 29 CFR 1910.147. Portions of the troubleshooting activity may be infeasible without these hazards present.
- Time pressure: Restoring operation of failed equipment often involves an explicit or implicit sense of urgency.
- There are effective methods for addressing each challenge, most of which require a combination of advance preparation and management commitment.
Tools to Increase Children and Teenagers’ Awareness of Electrical Risks
Danilo Ferreira de Souza, Walter Aguiar Martins Junior, and Edson Martinho
Accidents of electrical origin, especially involving electric shock and fires, are increasing in Brazil. The majority of accidents can be avoided by simple actions increasing the awareness of the risk. One of ABRACOPEL’s – (Brazilian Association for Awareness of the Dangers of Electricity) actions that has significantly helped to increase the awareness among children and teenagers was the Essay, Drawing, and Video competition themed “Safety with Electricity”.
This project will be twelve years old in 2023 and has boosted public and private school students’ engagement in this theme. The teachers participating in the project encourage students between 06 and 10 to produce drawings about the electrical risks. And teenagers between 11 and 18 are encouraged to create essays or videos on how to use electricity safely. Abracopel has received an average of 5,000 contributions per year. Through the preparation for the competition, these children or teenagers’ impact 5 other people and thus extend the reach of the project. The winners of the competition receive Tablets, Prize and Certificates. Thus, this article presents the project and its main results in raising awareness among the lay population about the dangers of electricity.
Utility Contribution to Arc Flash Studies
Tracy Roberts and Drew Thomas
The utility contribution input to an arc flash study has a significant effect on the output incident energy. Accurate input data can be difficult to obtain from serving utilities or is not consistently available. Defaulting to infinite bus can provide non-conservative results.
This focus session poster will discuss the challenges with utility contribution with examples, and suggest approaches to calculate conservative incident energy when the utility contribution data is not made available.
Electric Shock Near Miss, an Ungrounded Messenger Cable
While troubleshooting a problem with a sewage lift pump level control, the electrician saw steam coming from the ground next to the concrete slab that the pump and motor starter was mounted on. The pump is in a remote location with the power fed from an overhead quadraplex, three phase conductors and one grounded messenger. The quadraplex terminates at a typical outdoor weather head and conduit going down to a local disconnect, all mounted on a power pole. The disconnect feeds the local combination motor starter and pump located in a small building adjacent to the power pole. It was found that at some point in the past, the original conductors in the conduit failed and were replaced with Type SO cord, probably as a temporary measure. Over time the SO cord deteriorated and one conductor was bare and in contact with conduit, energizing all conductive parts from the weather head to the motor. It was discovered that the grounded messenger was not connected at the next upstream power pole and the current was going into the ground at the concrete slab and local power pole ground rod. 252 volts was measured on the disconnect and motor starter enclosures to ground. Four people were exposed with two of them operating disconnects and touching the enclosures. Dry Type EH boots. Very lucky no one was injured or killed. More details will be provided in the paper and recantation.
Since its inception in 1992, the ESW has established itself as the industry’s premier electrical safety conference. We look forward to seeing you at the next ESW!