Incident Prevention Magazine

4 minutes reading time (702 words)

Hidden Traps of Generator Use and Backfeed

The small generator is a godsend to those who need electric power where no electricity is found and the popularity of generator use by homeowners is growing by leaps and bound. Unfortunately, not everyone who owns a generator uses it in the safest manner. As a result, they create hazards for utility workers who may be working in close proximity to homes and equipment that may be fed or – even worse – backfed from a personal generator.

Generators pose a risk of shock and electrocution, especially if they are operated in wet conditions. During spring and summer storms, you can’t escape the sound of small generator motors in suburbs and cities affected by power outages. If a homeowner’s generator is located in wet or damp location, avoid working close to it, especially if it’s in standing water or puddles. Stray voltage from the equipment can create shock or electrocution hazard.

How shock or electrocution occurs. If an ohmmeter is used to measure a person’s body from one dry hand to another dry hand, the resistance can be up to 500,000 ohms. Most of this resistance comes from the skin. Under these conditions, a 120-volt source may not be high enough to overcome the resistance of dry, calloused hands to result in a fatal injury. However, if a person has wet skin from perspiring, the resistance can be as little as 1,000 ohms. The injury can be fatal if contact is made with wet skin.

Because many people have made contact with a 120-volt source and were not killed, they mistakenly think that 120 volts does not kill. However, fatalities occur every year from contact with 120 volts. It’s not the voltage that kills, but the current which is a function of voltage and resistance. Current flow of as little as 100 milliamperes (0.1 amperes) can be fatal.

Other hidden electrical traps. Appliances should be connected to generators using heavy-duty extension cords specifically designed for outdoor use. The wattage rating for each cord needs to exceed the total wattage of all appliances connected to it. Extension cords must be long enough to allow generators to be placed outdoors and far away from windows, doors and vents to the home or other structures that could be occupied. Cords should be free of cuts or tears. Ensure plugs have all three prongs. Cords also need protection from becoming pinched or crushed if they pass through windows or doorways. Any of these conditions can result in an event or fire that may catch a utility worker off guard. Make it your business to understand your surroundings and how the actions of homeowners may compromise your safety.

Backfeed. Some innovative homeowners try to power their house wiring by plugging generators into wall outlets, a practice known as backfeeding. This is extremely dangerous and presents an electrocution risk to utility workers and neighbors served by the same utility transformer. It also bypasses some built-in household circuit protection devices. Never assume the equipment you are working on is in safe condition or de-energized, especially during a power outage. When possible, perform testing to prove that a backfeed situation does not exist.

Generators may poison the air in an enclosed location. When used in an enclosed space such as a garage or shed, generators can produce high levels of carbon monoxide (CO) within minutes. You cannot see or smell CO. You may still be exposed to CO even if you do not smell exhaust fumes. If a generator motor is heard where you work, investigate its use. Ensure it’s being used in a well-ventilated location. Doors and windows in close proximity should be closed, especially if windows are located at belowground locations such as basements or crawlspaces where heavier-than-air gases can collect and accumulate. If you start to feel sick, dizzy or weak while working near a generator, get fresh air RIGHT AWAY. DO NOT DELAY. The CO from generators can rapidly kill you.

Situational awareness is one of the greatest skills a utility worker possesses to keep out of harm’s way. Next time you hear the familiar hum of a small generator, make it your business to know how it’s being used. Your life could depend on it.

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Monday, 19 August 2019

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