What Happens If Lightning Strikes A Power Line?

Ossiana Tepfenhart
by Ossiana Tepfenhart

The other night, the area around my town had a major storm. It was a thunderbanger, with more lightning and thunder than I knew what to do with. Right across my street is a large power line. I couldn’t help but wonder what would happen if lightning decided to strike it. After a while, I decided to research what happens when lightning hits our power sources.

When lightning hits a power line, what happens is generally called a “flashover.” Most people recognize them when they see bright arcs hit their power lines. Flashovers are the main cause of short-circuited power lines as well as power surges that can damage appliances.

Curious about what happens when power lines are hit by lightning, or what can be done to prevent electrical damage during a storm? I understand that curiosity. Here’s the scoop behind one of the most striking aspects of nature and how it can affect your home.

What Causes Lightning?

In short, lightning is defined as an electrical discharge that occurs because of imbalances between either the ground and the storm clouds, or within the clouds themselves. When the upper atmosphere possesses cold, dense air and the lower atmosphere consists of warm, moist are, thunderclouds will develop. As this warm air starts to rise, cold air descends, and the moisture forms clouds.

As this cycle continues, friction between the frozen and liquid water particles create electrical charges inside these clouds. Once the electrical charge is great enough, the air between the ground and bottom of the cloud breaks down. This effectively some of the electrical charge to reach the earth below and present itself as what we know as a lightning strike.

What Happens If Lighting Strikes A Power Line?

What happens when lightning strikes a power line depends on where the lightning strikes. The best way to describe it in laymen’s terms is to say that a flashover happens. This is what causes those bright green and blue “spark shows” that you’ve likely seen on viral videos on YouTube. When a flashover happens, the power surges through the lines and can potentially damage lines.

A flashover will cause the power line that’s struck by lightning to short-circuit. This can lead to outages, but thankfully, there are ways that power lines can be augmented to protect homes and surroundings from fires, short-circuits, as well as appliance damage due to surges.

How Do Power Lines Get Protection From Flashovers?

A flashover can pose a serious problem to the power line system, homes, as well as your appliances. Thankfully, engineers have been able to find ways to reduce the potential for damage and limit outages. Some of the better protective features used include:

  • Circuit Breakers. It’s true. Power grids get circuit breakers too. When breakers pick up on signs of a short, they cut power to the affected area temporarily to help stop the short from spreading.
  • Shield Wires.Shield wires are specialized wires that are meant to reduce the chances of flashovers. Adding more to power lines can help absorb the “blow” of a lightning strike. However, it’s important that they are placed correctly, as a poorly positioned shield wire can allow a large number of lightning strikes to hit phase conductors, and result in flashovers.
  • Tower Grounding. When lightning strikes a power line, the power will run through the lines and eventually hit the ground. Having better grounding means that the towers that support the line will have better mechanisms to neutralize electricity—either through structural engineering or electrical means.
  • Insulation. Insulated electrical wiring will be less likely to experience a flashover, especially if it’s an induced flashover. Although it is difficult to increase insulation on existing lines, even small increases in length will improve insulation and reduce the risk of flashovers.
  • Transmission Line Surge Arresters. Also abbreviated as TLSAs, these devices are meant to help decrease the amount of energy transmitted as a result of a lightning-induced power surge. Their job is to limit the voltages between the tower structure and the phase conductors, which can prevent flashovers in both poorly shield designs and high-footing-resistance areas.

Not all safety methods will work in all cases. It’s up to utility companies to figure out which risk mitigation methods will work best with the power lines in your area.

Is There Any Way To Fully Prevent A Flashover?

While having safety measures can help prevent a flashover, there’s no guaranteed way to end flashovers. Lightning strikes are very unpredictable. Not all safety measures will be able to counteract the high voltage that lightning can bring. Moreover, some safety measures won’t work if lightning strikes certain parts of the power line.

Because there’s no way to counteract all flashovers, there’s always going to be a risk of a shortage. That’s why you still get to see so much footage from power lines that have been hit by lightning.

What Can Happen If A Flashover Occurs?

Flashovers are serious business and can cause a wide range of different problems. Most commonly, they can cause power outages. If a surge hits the line, there’s also a possibility that extra electricity could flow to homes. This can cause electrical failure in appliances and other items, even if you have a surge protector. In very rare cases, a flashover can also cause a fire.

With that said, most systems are able to handle mild lightning strike cases without any serious interruption to service.

Is It Possible to Know If Lighting Caused a Power Outage?

By using the figures from the National Lightning Detection Network (NLDN), it is possible to determine of a power line outage was caused by lighting. This data was developed over the past twenty years by EPRI, government agencies and various universities.

The NLDN is responsible before recording the exact time, magnitude, and location of the roughly twenty million lighting strikes that hit the ground in the United States each year. By analyzing historical data, and comparing it with the location and time of current disturbances, they can conclude whether or not lighting was the cause.

How Can You Keep Your House Safe During A Lightning Storm?

Knowing that lightning can quickly turn your home into a disaster area can be enough reason to start getting a little more protective of your home during that next storm. These tips and tricks can help keep your home intact during major lightning storms:

  • Avoid using water during the storm. Lightning and electricity can travel through water, which in turn, can put you at risk of electrocution and shorting certain appliances.
  • Unplug any equipment that is sensitive to electricity when you first notice lightning. A surge can easily destroy sensitive equipment like DJ turntables. Unplugging it will keep it safe from any surges that could potentially shock your system. If you want to stay safe, unplug everything and just stick to using mobile devices for the time being.
  • Don’t use corded devices during a storm. A surge sparked by a lightning strike can cause electrocution or a brownout. By not using corded devices, you reduce the chances of having a power surge affect your devices.
  • Avoid placing electronics on concrete walls or flooring. Believe it or not, concrete can conduct electricity fairly well. If lightning hits near your home, this could potentially lead to a shortage in the wiring of your favorite electronics.
  • Stay indoors. This is common sense, but always is worth repeating. As the old adage goes, when lightning roars, stay indoors.
  • Close windows and doors. Keeping away from the foul weather isn’t enough. Keeping your home closed off to the elements is what can really make or break your home’s safety.

Related Questions

Can engineers tell when a short circuit is caused by lightning? 

Believe it or not, they can! Lightning flashovers tend to cause specific patterns that engineers can pick up on.

Do cellphones attract lightning? 

This is a common misconception that’s often based on the knowledge of metal conducting electricity. Though most people think otherwise, cellphones, jewelry and other knickknacks don’t attract lightning. Lightning is far more likely to strike tall, bare places. Wearing metal and having metal items on your body makes no difference when it comes to a lightning strike.

Can you use the toilet during a thunderstorm?

You really shouldn’t unless you have to. Though it’s as rare as getting struck by lightning, there have been cases were flushing a toilet during a thunderstorm caused the toilet to explode. This is because the electricity in the water combined with methane gas from waste, causing a bomb-like effect.

Has anyone died from taking a shower or a bath during a lightning storm?

While it is exceedingly rare, there are handfuls of people who have died as a result of showering during a storm. Around 16 people out of every 100 million will die from taking a shower during a lightning storm. Their official cause of death is usually deemed to be electrocution, but can also be linked to head trauma from falling after being stunned from the shock.

Ossiana Tepfenhart
Ossiana Tepfenhart

Ossiana Tepfenhart is an expert writer, focusing on interior design and general home tips. Writing is her life, and it's what she does best. Her interests include art and real estate investments.

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