Canadian Occupational Safety

August/September 2016 21 great risk. If an individual is touching the exterior of energized equipment at the time of the contact, then injury is imminent. If an individual is standing nearby and the electricity enters the ground, injury is also is quite likely." When equipment contacts a power line or a line falls to the ground, an electrical current may fl ow into the ground creating a "pool" of electricity in the surrounding ground. The volt- age is highest close to the equipment; farther away, it gradually drops off. The electrifi ed ground will energize anything that touches it. This poses a particular risk to the equipment operator, Saint says. "It's a scary situation, when the tires on your truck are smoking because of your contact with the power lines. The normal driver wants to jump out, but that can be very dangerous," he says. "If you get out of the truck, you can be injured or killed because the electric- ity is travelling through the ground. If you take a step, the electricity can travel up from the ground through one leg and then down the other leg, passing through your heart as it does it." Thus, if equipment touches a line, he says, workers should know to stay inside their vehicle. "Stay in your truck. The rubber tires, although they may smoke, will still insulate you from the danger. Ask someone to call 911 and have the utility also come out and disconnect the line," Saint says. If an operator or driver must leave the vehicle — in the event of a fi re or other hazard — they need to get out without touching the vehicle and ground at the same time. The worker should jump about 45 to 60 centime- tres away from the energized vehicle, landing with feet together and hands by the sides. Keeping the feet touch- ing, the workers must then shuffl e away, never allowing the heel of one foot to pass the toes of the other. Alternatively, hop with both feet together until at least 10 metres away. Other workers can avoid the poten- tial of energized ground by staying at least 10 metres away from operating machinery — if a boom is moving, for example. Wait until the machinery is not operating before approaching it. The large rubber tires on trucks and heavy equipment constitute a further risk because contact with high-voltage power lines can cause tires to explode. Extreme heat causes hydrocarbon vapours to be released inside the tire, which in turn causes the air pressure and temperature to rise drastically. If the vapour, which is highly fl ammable, comes in contact with very hot oxygen, it will ignite and the tire will explode. Workers can be injured or killed by fl ying tire or wheel parts, so anyone in the area who sees a vehicle smoking should not approach it. SAFE WORK PROCEDURES Dwight Larkin, health and safety co-ordinator at Fermar Paving, a road construction and paving com- pany based in Rexdale, Ont., says his workers do a lot of work near both overhead and underground wires. When a job site opens and before any work starts, he says, supervisors check to see where overhead wires are and obtain underground "locates." They then put up signs warning of overhead wires. These signs are located near the power lines and serve as a constant reminder to workers. Warning signs should be specifi c (stating the hazard and voltage) and located so at least one is always vis- ible to operators working in the area. They should also be legible in all con- ditions, such as rain and night, during which work is done. Then, Larkin adds, every day, before work starts, supervisors and workers do a site assessment, discuss all job-site hazards and review the measures they can take to prevent incidents. During the site assessment, workers should be looking around, both at the ground and up in the air. It's also important to identify where people will be working near power lines and assign others to be spotters, or signallers: workers who stand and watch and can warn a driver when equipment is getting too close to power lines. Supervisors also do weekly site inspections and tailgate meetings, as well as additional tailgates as needed Larkin says. "If we have a near miss on one job site, then we try to discuss that near miss at all the other job sites, so if they come across a similar situation, the workers understand what they should be doing." To ensure workers are follow- ing proper procedures, Larkin and another safety manager visit job sites every couple of weeks. "And if we see something we don't like, then we'll stop and explain why they have to do what they have to do." Generally, the employer is respon- sible for determining the voltage of power lines on a work site and for informing workers of the location and voltage of high-voltage lines. Material and equipment should not be stored under power lines. Workers and supervisors should look for overhead lines before moving ladders, rolling scaffolds or elevating work platforms. Melody Mateev, HSE co-ordinator at Edmonton-based ATCO Electric, a utility with 80,000 customers across Alberta, says companies that need to work near power lines should contact their utility before starting a job so the utility can measure the voltage. Companies should also make a work plan and know the height of their equipment. It's important for workers to know and maintain the regulated safe distances, or "limits of approach," the minimum distances between power lines and people, machinery or tools required to prevent direct contact and arcing, Mateev says. In Alberta, workers must keep 7 metres away from power lines, she adds. In Nova Scotia, the limit of approach is 6 metres. In New Brunswick, that limit is 3.6 metres. In other jurisdic- tions, such as Ontario, Quebec and B.C., regulations put the minimum safe distance at 3 metres (although B.C. Hydro advises 20 metres). These distances vary depending on the volt- age. In Ontario, for example, the distances are: • 750 to 150,000 volts — 3 metres • 150,001 to 250,000 volts — 4.5 metres • 250,001+ volts — 6 metres. In Newfoundland and Labrador, Curran says, anyone working around power lines must maintain 5.5 metres from energized, high-voltage power lines. "There is also a legal obligation for workers who operate equipment capable of contacting power lines to complete a provincially prescribed power-line hazard training course. In some cases, permission can be given by the electrical utility to go within three metres," he says. At the time of his accident, Weber was not expected to survive. However, after six years of surgeries and physio- therapy, he was able to go on with his life. Now a safety offi cer with the Sas- katchewan Health Region, he spends much of his time doing presenta- tions, encouraging workers to speak up when they have concerns about a job and promoting safe practices, par- ticularly around power lines. Linda Johnson is a freelance journalist based in Toronto. She can be reached at lindajohnson@sympatico.ca. great risk. If an individual is touching the exterior of energized equipment at the time of the contact, then injury is imminent. If an individual is standing nearby and the electricity enters the ground, injury is also is quite likely." When equipment contacts a power line or a line falls to the electrical current ground creating a "pool" of electricity in the surrounding ground. The volt- age is highest close to the equipment; farther away, it gradually drops off. The electrifi ed ground will energize anything that touches it. This poses a particular risk to the equipment operator, Saint says. "It's a scary situation, when the tires on your truck are smoking because of KEEP WELL BACK: Electricity can arc from a power line to any object (including people) if it gets too close. Make sure workers know the limits of approach and how close is too close when it comes to power lines. BEWARE OF EXPLODING TIRES: Electricity can heat the rim of a tire, raising the temperature of the air inside. This almost instan- taneous expansion can cause a violent explosion of hot air and rubber shrapnel. In fact, the danger can last as long as a full day after a power-line contact. LOOK UP. LOOK OUT: Often incidents happen late in the day when workers may be tired and rushing to fi nish a job. Electric- ity doesn't care about the end of a shift, but it can end a life. If a worker is lucky enough to survive a contact, it can leave severe burns where it enters and exits the body, not to mention major damage to the heart, organs, nerves and muscles.

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