Are shipping container homes safe from lightning?

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With a full steel body of shipping containers, the fear of lightning strikes is quite understandable. But don’t refrain from pursuing your shipping container home ownership without thoroughly looking into the concern. This article shall lay out for you all the reasons why lightning strikes a house, and assure you that Shipping containers are as safe a houses to live in as any other.

Shipping container homes do not make you vulnerable to lightning strikes. Just like a car with a complete metal body is safe from a lightning strike, so is a shipping container. The steel body of a shipping container acts as a faraday cage and transfers the lightning to the ground through its body without affecting anything or anyone inside.

Things you should do to protect yourself and your home from fatalities of a lightning strike

  • Insulate your container properly.
  • Avoid touching any metal faucets at the time of thunderstorm
  • Install lightning rods and grounding kits in your home.
  • Avoid touching the exposed parts of your metal container in case of a thunderstorm
  • Ensure that the door and window opening is properly sealed.

 

How and Why Lightning Strikes occur?

Lightning often strikes the tallest objects in the vicinity. This is because lightning flows through the point of least resistance. As the air that transports it from the clouds has very little conductivity, the lightning automatically seeks more conductive objects, such as buildings and trees, on its way towards the ground. This is why tall trees and buildings get hit more often by lightning, as they are the first ones in its path.

In simpler words, the lightning would take any alternate path that could help it reach to the ground faster than the air.

Chances of lightning strike in a regular house v/s shipping container

Lightning strikes are a real thing and something that should be considered seriously , especially if you live in a thunderstorm prone area. It can strike an area 15 miles away from the area the thunderstorm is actually occurring. So, you might not even see it coming. It is best to be prepared for it if the chances in your region are high.

According to statistics, Lightning strikes can occur in 1 in 200 homes, in America. Indeed, this number is very disturbing. 
In some states, the lightning rod installation is an important part of the building code.

The chance of lightning striking your container home depends on two factors:

Height: So, the chances of lightning getting attracted to your shipping container home are more only when your container home is the highest in your area, (i.e., higher than any tree, tower, or other building in the close surroundings), or if the there are no other tall structures around your exposed shipping container. 
Only then will the lightning seek the help of your container home to boost its journey to the ground.

Note: If you have a tall tree in the close vicinity, that could also make your home vulnerable. 

Material- The lightning is looking for the least resistant materials. So, although the steel body of your container could be a factor to attract lightning, the risk of your container home being hit by lightning is the same as any other conventional home. As conventional homes also carry internal wiring, conduits, copper plumbing that can attract lightning. A container home can prevent lasting damage.

If your container is exposed, then it has a higher chance of getting struck than if it is insulated and covered with siding.

In the next section, let’s understand, what will happen if your shipping container home is caught by a lightning strike.

How Shipping Container home would react to a lightning strike.

When a high-powered lightning strike hits the container home, the container becomes a Faraday cage, and through skin effect, the body of the container keeps the current to the skin so anything or anyone inside is not affected or electrocuted.

Faraday Cage

Faraday cages are named after scientist Michael Faraday, who invented them in 1836

A Faraday cage creates a barrier between the internal components of a device and the external electric fields. It works because an outside electric field causes a redistribution of the electric charges within the enclosure’s conducting material, which in turn cancels the field’s effect in the cage’s interior.

In simpler words, the current will go into the ground through the steel body of the container and will keep current to the skin and not electrocute anything within. 

The same phenomenon works in the case of a car. It’s not the rubber tires that make a car a safe place in case of a lightning strike, it is the metal body.

However, for this to happen, there should be no cracks or voids in the envelope, otherwise, the circuit will be broken, and the current will travel to objects in the interior to seek an alternative path for grounding.

What if you are touching the Container while Lightning Strikes?

If the container walls are exposed, then there is a chance that touching the exposed container wall will give you a shock or get you electrocuted (it can be fatal). But in most cases, the container homes are covered with sidings on the outside and insulations on the inside, which highly reduces the risk of that happening.

If you live in a thunderstorm prone area, and there is a good chance of lightning, you could install a grounding system in your container home. However, it is not necessary. As mentioned before, your container will facilitate the current, and then if there is no way to go to the ground, the current will adapt any air gap between the container and ground to reach the ground.

In case of a lightning strike, ensure that:

  • The faraday cage effect will not cause any damage to the interior of the container home, if insulated properly. But it is important to not touch the metal walls.
  • Try to avoid touching any metal faucets, nail, stud, or handles. The lightning can quickly grab on to any good conductor it finds, and thus the metal faucets are especially vulnerable as the continuous plumbing line can carry the lightning. However, with the new PVC plumbing, chances of that happening have reduced.
  • Avoid using any electrical appliance during a thunderstorm. If used in times of a thunderstorm, the electrical appliances can be damaged. In fact, the appliances that can be unplugged should be unplugged to break the circuits and protect the appliance.

Grounding a Shipping Container Home:

Grounding a home is a common practice across all conventional practices, and it is not so different for a shipping container home. Grounding is recommended when you have tall trees very close to your container home, which could put your container in a vulnerable location, when your container home is the only tall object in the vicinity, or if your region is prone to lightning and thunderstorms.

There are several ways of grounding your container home:

Iron rods, 
The first and simplest way is to attach steel/iron grounding rods to the base of the container which will reach the ground through the foundation. That will lead the lightning right to the ground, thus protecting prolonged faraday cage impact. 

This is the easiest and cheapest way to ground your container home.

Lightning protection kits:

In conventional homes, a lightning rod is attached to the roof, that carries the current to the ground through an earthing wire/ copper wire. But since a shipping container body is steel, a rod on the roof might not be necessary. If you have a secondary roof (as discussed in How to keep the container home cool), then you might add the lighting rod to the secondary roof and ground it through its columns.

The earthing wire is connected to the steel body of the container and then attached to the lightning rod, dug deep into the ground.

Along with the lightning rods that go 10-20ft into the ground, a grounding mechanism is also installed in the main electrical control box of your house, that will protect your appliances and wiring from the fatal effects of lightning.

Note: the lightning travelling through plumbing is highly unlikely in today’s time as most plumbing pipes are PVC pipes.

Final Words

The possibility of your container home being struck by lightning is the same as a conventional home. Although there is nothing, we can do to prevent it, the grounding systems ensure that the strike does not cause any lasting damages to your property and you. So don’t let this affect your decision to own a shipping container home.

References:

https://twielectric.com/ground-a-house-electrical-system/

https://shop.ingeniousstorage.com/blogs/news/should-i-ground-my-shipping-container-grounding-a-seacan

https://physics.stackexchange.com/questions/242156/will-i-get-electrocuted-holding-the-container-inner-surface-while-lightning-stri

https://en.wikipedia.org/wiki/Faraday_cage#:~:text=A%20Faraday%20cage%20or%20Faraday,who%20invented%20them%20in%201836.

https://www.allaboutcircuits.com/textbook/alternating-current/chpt-3/more-on-the-skin-effect/

https://mrelectric.com/blog/should-i-install-a-lightning-rod

https://www.totalvegasrealestate.com/indoor-lightning-safety-guide/