The growth in renewable energy power generation will continue into the future. What has been lacking is focus on the electrical hazards in construction and fabrication, commissioning, operation, and maintenance. However, requirements in NFPA 70E, Standard for Electrical Safety in the Workplace and CSA Z462, Workplace electrical safety Standard do apply to renewable power generation.
ARC FLASH AND SHOCK HAZARDS IN RENEWABLE POWER GENERATION
Renewable power generation is not new technology. It has been adopted in Canada, the United States, and globally for decades.
- A strong installed base exists in wind turbine power generation and large commercial solar power farms, and with new battery technology, large-scale battery storage will begin to be installed.
- Large-scale solar power generation development (e.g. 100 MW, 500 MW, 1,000MW, or larger) has lagged wind turbine power generation, but has accelerated in the last three to five years.
- Installation of large-scale battery storage systems is relatively new and will experience significant growth.
In Canada, according to Natural Resources Canada — in addition to wind and solar power growth — development of other renewable power generation including hydro, solid biomass, ethanol, renewable municipal waste/landfill gas, biodiesel, and tidal has also accelerated in the last 15 to 20 years.
Additionally, technological development and competition in battery technology has resulted in lower prices and greater capacity. This is expected to result in accelerated growth in adoption.
The development growth has come with the additional exposure of construction and fabrication, commissioning, operation, and maintenance workers to the electrical hazards of arc flash and shock from working on both low- and high-voltage electrical equipment.
NFPA AND CSA STANDARDS
NFPA 70E and CSA Z462 have been adopted across the USA and Canada by industrial, commercial, and institutional business sectors as the industry’s best practices for the development and implementation of policies, practices, and procedural requirements for electrical safety and the effective management of arc flash and shock hazards. The adoption and application of NFPA 70E and CSA Z462 to renewable energy power generation would be considered good due diligence to applicable OSHA and provincial or territorial occupational health and safety regulations.
The 12th Edition of NFPA 70E published in September 2020 included a new Battery Risk Assessment method (Figure 1) for work on batteries in Annex F Risk Assessment and Risk Control, F.7, and Figure F.7: Assessing Hazards Associated with Work on Batteries. CSA Z462 published its 5th Edition in January 2021; it does not include this flow chart related to batteries.
As defined by the Canadian Electrical Code and the National Electrical Code, low-voltage (≤1,000 V) and high-voltage (≥1,001 V) power generation is installed. Solar power generation occurs at DC voltages that are considered high-voltage: 1,500 VDC. In its 2021 Edition, CSA Z462 will apply to electrical equipment with a voltage greater than 30 V AC or 60 V DC (CSA Z462, 2021 Edition, Clause 18.104.22.168.3), while NFPA 70E still retains a 50 V AC or DC low-voltage threshold.
The NFPA 70E and CSA Z462 standards are based on work tasks and are 100% focused on risk assessment. Specific, defined work-task descriptions can be found in NFPA 70E Table 130.5(C) or CSA Z462 Table 2 for both AC and DC low- and high-voltage electrical equipment. Table 1 highlights some of the work tasks that would normally be performed related to construction and fabrication, commissioning, operation, and maintenance of renewable power generation.
Significant electric shock and arc flash hazard exposure is related to isolation and any diagnostics or troubleshooting work tasks related to renewable energy power generation.
During the construction of renewable energy power generation facilities, tasks related to commissioning the power distribution system will expose qualified persons to the electrical hazards of arc flash and shock. Following commissioning, ongoing operation and electrical equipment maintenance will expose operations and maintenance employees or contractors to the electrical hazards of arc flash and shock. Renewable power generation also includes construction of additional overhead power lines for distribution and transmission with related outdoor high-voltage substations, and this energized electrical equipment poses a significant shock and electrocution hazard and arc flash.
SEQUELA EFFECTS OF ELECTRICAL SHOCK
The electrical shock hazard has been neglected. Electrical workers have accepted being shocked as part of the job — a right-of-passage, a badge of honor — and they may not even be aware of the long-term sequela health effects of receiving multiple low-voltage electrical shocks and how it may have impacted them. Currently, two facilities are formally recognized for formal research and treatment: the St. Johns Rehab Centre, Electrical Injury Program in Canada and the University of Chicago, Chicago Electrical Trauma Rehabilitation Institute (CETRI) in the United States.
When a worker is exposed to electric shock hazard, there are two possible outcomes:
- A shock is received, and the worker survives.
- Or they die.
Electrical incident statistics confirm that fatal electrical injuries from shock occur at an alarming rate — on average still once a day or more in North America. What is not published in electrical incident statistic reports is the number of electrical workers who suffer from the long-term effects of receiving multiple low-voltage (<1,000V) shocks. The medical term for this is “sequela.”
A sequela is a pathological condition resulting from a disease, injury, therapy, or other trauma. Typically, a sequela is a chronic condition that is a complication which follows a more acute condition. It is different from, but is a consequence of, the first condition. Source: Wikipedia
We know the short-term effects of receiving an electric shock. As noted above, you survive the electric shock or you die. Table 2 lists the short-term immediate effects of receiving — but surviving — an electric shock.
The amount of current, the current flow path through the human body, and the frequency and length of time the current flows through the human body determines the probability of heart fibrillation. Male and female body resistance will be different, and added muscle mass increases conductivity. Wet or dry skin at the point of current entry will also impact current flow, and the number of times an electric shock is received impacts the long-term effects and possibly sequelae.
If you are an electrical worker reading this article, you may have long-term sequelae effects from been shocked multiple times throughout your career at 120 VAC, 208 VAC, 240 VAC, 277 VAC, 347 VAC, 480 VAC, or 600 VAC. If you have some of the symptoms listed in this article, you may want to follow up with your family physician. The potential long-term sequela effects from receiving multiple, low-voltage electric shocks include psychological, neurologic, or physical symptoms.
- Psychological Symptoms. Behaviour changes and attention span issues. You may be irritable, get frustrated, experience anger, and may be physically aggressive. You may experience depression and posttraumatic stress disorder depending on whether you experienced “no-let-go” or became unconscious due to the shock exposure. Other sequelae include insomnia, anxiety, fear of electricity, panic attacks, guilt, and moodiness.
- Neurological Symptoms. You may experience memory loss, numbness, headaches, chronic pain, poor concentration, carpal tunnel, seizure disorders, dizziness, tinnitus, and tremors.
- Physical Symptoms. Generalized pain, fatigue, exhaustion, reduced range of motion, contracture, night sweats, fever, chills, or joint stiffness may be experienced.
The effects listed can change or may be more severe depending on whether the shock was a momentary contact or resulted in no-let-go, the path the current flowed through the body, and the duration and amount of current.
John Knoll’s Story
John Knoll is a Master Electrician, and a Professional Electrical Contractor (PEC) with the Electrical Contractors Association of Alberta (ECAA) and resides in Edmonton, Alberta, Canada. John is currently not working in the trade and is suffering from sequalae related to receiving multiple low-voltage shocks while at work starting when he was an apprentice and continuing while he was a journeyman electrician. John worked in the non-unionized side of the trade for most of his apprenticeship and career. He told me, “As an apprentice trimming out lighting circuits in apartments, we played games about being shocked at 120 VAC. We were not taught to fear electricity or respect it. I was never concerned about 120 VAC, 240 VAC. I didn’t consider it an issue to receive those shocks. I always said I would rather receive one knowing it was coming than not knowing. So after tick testing, we would touch the wires, because sometimes the tick tester lied, and it was better to know it was coming. It was the most we were able to do most times not being supplied the proper PPE or training to do our duties.”
The story of John’s career is very common. John started in the electrical trade in 2005 and worked on energized 120/240 VAC single-phase and three-phase 208 VAC panelboards as an apprentice. He received shocks as early as the first week in the trade. John states, “I was probably shocked up to 500 times,” and I have talked to other electricians who say they were shocked hundreds of times during their career. John explains, “The electricians I worked with when I was an apprentice never identified the hazards and long-term effects of electric shock. There was no formal training, and no personal protective equipment was provided. If we wanted a tick tester, we had to buy it ourselves. ‘Live’ work was not questioned. We had to work energized because we couldn’t de-energize parts of the job. We cut in panels while energized and rarely could turn off the power, as it impacted the other trades. I didn’t receive any training on lockout until I worked the last few months of my fourth period in the Union.”
John’s perception of shock and his sequela changed when he was shocked at 347 VAC. “That shock was different,” he says. “I was held and could not let go. I knew I was going to die, and I had no control of my body. I was saved by gravity when I fell off my ladder. I thought I was dying; the pain was unbelievable as I lost the ability to breathe. At that point,” John says, “I had a new-found respect and fear of electricity.”
In John’s case, he experienced psychological, neurological, and physical symptoms he did not know could be attributed to receiving multiple, low-voltage shocks throughout his career. When John described his injuries, I found it unbelievable, but based on information published more than 10 years ago by Dr. Joel Fish, who at the time was practicing at St. Johns Rehab Centre in Ontario, the long-term sequela effects of electric shock are real.
John moved on in his career and had his own company from 2010 until he could no longer work due to escalation of his symptoms. He believes he began experiencing symptoms as early as two years into the trade and began seeking chiropractic and massage care —known relief for the nerve pain caused by the long-term sequelae effects of electric shock. In 2016, his life began to change rapidly, and looking back now, he knows the multiple electrical shocks he received led to deterioration in his mental and physical health and directly impacted his personal life, as he was divorced from his wife and had issues with his friend and business partner.
John’s comments about working on energized conductors and circuit parts were and perhaps still are the norm in the industry. In fact, his comments align with the results of a shock research project completed by the British Columbia, Canada, Technical Safety British Columbia (TSBC). In February 2019, the TSBC published a report related to shock hazard in “Negotiating Safety – Understanding the Behavioral and Sociocultural Factors Related to Electric Shock.” Based on interviews and surveys, the report categorized the reasons electricians have worked and continue to work energized: societal, sectoral, organizational, interpersonal, and individual (Figure 2). The report concluded that poor training, poor work practices, complacency, not refusing to work energized, “I thought someone else had turned off the power,” and peer pressure (e.g. loss of job, keep the boss happy, rebuked by other workers) influenced why working energized was never questioned.
I believe John’s story is not an isolated case. There are hundreds, potentially thousands, of electricians in Canada, the United States, and internationally who have long-term sequelae and have not correlated them to receiving multiple, low-voltage shocks throughout their careers. The psychological, neurological and physical health issues, the impacts on families, and the potential impact of not continuing in the trade with its resulting financial impacts are significant. If you are an electrician and are experiencing symptoms listed in this article, they can most likely be attributed to receiving multiple, low-voltage electric shocks while working. A big shout out and “thank you” to John Knoll for sharing his story, emotions, drive, and entrepreneurial spirit.
The bottom line is that electrical workers have been shocked as a normal condition of doing their jobs with a complete lack of awareness of the potential long-term effects of receiving multiple, low-voltage shocks throughout their careers. From 1942–1960, the American Electricians’ Handbook taught electricians that the human body could be used to detect voltages up to 250 VAC by touching with the hands. The chapter on Measuring, Testing, and Instruments said, “Electricians often test circuits for the presence of voltage by touching the conductors with the fingers. The presence of low voltages can be determined with tasting.”
Yes, there have been changes in the last decade in Canada with the publication of CSA Z462, Workplace electrical safety Standard in 2009. NFPA 70E, Standard for Electrical Safety in the Workplace, first published in 1979, has also made a difference, but the focus has been on arc flash and not shock. For the future, shock needs to be a priority!
APPLYING NFPA 70E AND CSA Z462
As noted previously, the NFPA 70E or CSA Z462 standards are work-task-based. The next consideration is the voltage of the electrical equipment the work task will be completed on and the condition of maintenance of the electrical equipment. NFPA 70E and CSA Z462 require a risk assessment procedure to be implemented for defined “jobs” that would include the execution of a single or multiple work tasks. Two separate risk assessments are completed underneath the job’s risk assessment procedure for each work task: a shock risk assessment and an arc flash risk assessment.
Based on the work tasks listed in Table 1, construction/fabrication, commissioning, operation, and maintenance of renewable energy power generation require effective hazard identification and risk assessments to be completed for “jobs” that may include the work tasks listed.
The requirements of NFPA 70E, Standard for Electrical Safety in the Workplace and CSA Z462, Workplace electrical safety Standard do apply to energized electrical equipment related to renewable power generation.
Marni L. Wesner, MD, MA, FCFP, DipSportMed, and Dr. John Hickie, MD, MSc, CCFP, CCBOM. “Long-Term Sequelae of Electrical Injury.” Canadian Family Physician, CFP-MFC, Official Publication of The College of Family Physicians of Canada, September 2013. Online: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3771718/.
Clifford C. Carr, EE, PE. American Electricians’ Handbook, Fifth Edition, Tyrell Croft Consulting Engineers. McGraw-Hill Book Company, Inc., 1942.
Technical Safety British Columbia (TSBC). “Safety Stories: Electric Shock.” Online: https://www.technicalsafetybc.ca/State-of-Safety-2018/safety-stories/electric-shock.
St John’s Rehab Centre. Electrical Injury Program. Online: https://sunnybrook.ca/content/?page=sjr-patvis-prog-electrical.
University of Chicago, Chicago Electrical Trauma Injury Institute. Online: https://en.wikipedia.org/wiki/Chicago_Electrical_Trauma_Rehabilitation_Institute.
Government of Canada. Online: https://nrcan.gc.ca/science-data/data-analysis/energy-data-analysis/energy-acts/renewable-energy-facts/20069.
Terry Becker, P.Eng., CESCP, IEEE Senior Member, is an Electrical Safety Specialist and Management Consultant. He is the first past Vice-Chair of CSA Z462, Workplace electrical safety Standard Technical Committee and currently a Voting Member and Clause 4.1 and Annexes Working Group Leader. Terry is also a Voting Member on CSA Z463, Maintenance of electrical systems Standard and a Voting Member of IEEE Std. 1584, Guide for Performing for Arc-Flash Hazard Calculations. He has presented at conferences and workshops on electrical safety in Canada, the United States, India, and Australia, and is a Professional Engineer in the Provinces of British Columbia, Alberta, Saskatchewan, Manitoba, and Ontario.