Your home, your business, and every other building in Central Iowa is powered by the same electrical grid. High voltage lines deliver electricity from power plants to your home where an electrical panel breaks up that power into separate circuits. While we can help you with anything on this side of the transformer, from circuit panel connections to any residential electrical work, it’s up to you to keep yourself safe around power lines.
Construction of the Electrical Grid
Our power system is extremely well-designed. While we can’t actually control which direction electricity flows, we do control which paths are open and can measure how much electricity is flowing over a certain line. Power stations generate vast amounts of electricity and then push them out onto the grid. Transformers take this energy and “step it up” by raising the voltage. This increase in voltage reduces the amount of current on the line itself. Power lines do this by design because it reduces the amount of electrical energy lost to grid itself as power travels from a power station, to a substation, to your building.
But the energy-efficiency steps don’t just stop there. High wire lines are made from aluminum rather than copper. While copper is better at conducting electricity, it’s expensive and heavy. By constructing power lines out of aluminum, we can develop longer cables with fewer interconnects.
As power travels across lines, it reaches substations which help to regulate flow. Connecting switches on power lines work to direct the amount of energy moved between cities and neighborhoods. A careful balance must always be maintained between the amount of energy being used, known as resistive load, and the amount of energy delivered. When these two values vary by a large margin, the power system desynchronizes and the system shuts down.
This is, of course, a very simplified description of our rather complicated power grid. But the short form is that power plants generate electricity, which travels across power lines to be delivered to cities, homes, and businesses.
Home Safety
Power lines, whether they’re high-voltage cross-country transmission lines or feed lines that run to your house, are extremely dangerous. They’re separated into a positive line, a negative line, and a common or ‘ground line’ in much the same way that electrical wiring in your home is structured. This is why it’s dangerous to play around power lines. When a connection is made to a power line, even an insulated line, you create a shorter path to ground than the power line currently has. Electrical energy will leap across this short, travelling through you in the process. Since you have a higher resistance than aluminum does, all that voltage is going to use a lot of current to pass through you, resulting in burns and likely death.
You may be thinking “Wait a minute, electricity always takes the least resistant path to ground. Why would it flow through me rather than the conductive aluminum?” Aluminum is less resistant, but there is more ground to cover. The total resistance of the entire power grid, plus your home and any other resistive loads on the way is going to be much higher than the resistance of your person.
Always double check for high-wire and ground lines before performing any work outside. To stay completely safe:
- Never carry tall objects such as ladders near power lines.
- Avoid letting children play near power lines or on power poles.
- Call your local utility provider before doing any digging in your yard to avoid severing a buried electrical cable.
- Never allow children to throw things at power lines, transformers, or the connection pole for your home.
If there has been damage to your home or the power panel, you can always call Custom Electrical Services for repairs. From the power pole nearest your home on, you’ll need to contact a local utility provider.
Downed Power Lines
Sometimes you’ll come across a downed power line. While this could be part of a deactivated line that is currently being worked on, it’s likely due to damage from storms or sagging cables.
It’s interesting to note that power lines can actually appear to sag as they carry more load. This isn’t because the power line is heavier but it is due to the amount of electrical energy travelling on the wire. As current increases through the wire, the temperature rises. Aluminum expands as it heats, causing the length of the wire to increase. Since the wire can’t stretch out, it bows in the middle making it appear to sag. At times, the cable can increase enough to cause a short to ground. If you happen to notice cables that are sagging excessively, always call your local utility to let them know.
Downed power lines are always dangerous! Even a cable that looks like it could be a phone cable or appears to be dead can be dangerous. Downed power lines often do not spark and they don’t hum like other high wire lines do. If you see a downed power line, call 911 and keep others away until help arrives.Never approach, even if you think it’s safe.
Of course, that’s all well and good when you see a downed power line from a distance, but what do you do if you find yourself trapped under a power line while in your car? This can happen after a collision with a power pole or during a storm. If your car is still drivable, back away from the power pole slowly until you are no longer near the downed power line. Otherwise:
- STAY IN YOUR CAR – If you leave your car you risk shock and electrocution. Do not exit the vehicle and do not open the door.
- Call 911 immediately – tell them where you are and explain the situation.
- Keep others away – crack a window that is distant from the power in and tell others to stay back. If your phone isn’t working ask them to call 911.
- Wait for help to arrive
Of course, this isn’t full-proof. If you need to exit the car for any reason (the car is on fire, for instance), you need to be extremely careful in how you exit.
- Open a door that has direct access away from the power line.
- Do not touch the exterior of the car and do not step out of the car.
- Keep your feet together.
- Jump away from the car, keeping your feet firmly together. Land on your feet, don’t jump so far that you fall over.
- Keeping your feet together, take short hops or shuffle your feet to get away from the vehicle. When you think you’re far enough away, slowly and carefully slide one foot away from the other. If you feel a tingle you are not far enough away yet.
The Puget Sound Electrical utility has a great dramatic video of a similar situation that explains why and how this works:
And that’s it. Stay clear of power lines for play and work, always call ahead before digging in your yard, and always call 911 immediately when you see a downed power line.
For the best in quality electrical repair work and installations, contact the professionals at Custom Electric! Be sure to check back here each week for helpful advice, news, and guides or follow us on Facebook and Twitter!
