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I am building a house made of containers. The container is placed on 1 feet high concrete and no parts touching the ground but the distribution box has a wire to the grounding copper.

I read about Faraday's Cage but just wanted to know more about the risk.

Well, on the event of lightning strike, will I get electrocuted if I touch the inner surface of the container? Because most people standing inside the cage doesn't touch the cage by hand. They stand in the middle.

Thank you

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  • $\begingroup$ It depends. A Faraday cage is made to form an alternate path for electricity to travel from source to ground without travelling through the object inside the cage. So if the Cage is complete then there is no problem in touching the inner surface. That is why people wear cloths out of metallic mesh which also acts as a Faraday cage. But remember the cage should be complete. $\endgroup$
    – hxri
    Mar 8, 2016 at 4:10
  • $\begingroup$ For clarification, I'm guessing from the context that the containers are metal? $\endgroup$
    – Red Act
    Mar 8, 2016 at 4:11
  • $\begingroup$ @RedAct, yup the container is made from corten steel. I don't place any insulation inside, so basically the inner part of it are totally exposing the metal part. $\endgroup$
    – Pet
    Mar 8, 2016 at 4:19
  • $\begingroup$ The answer to that is not in physics textbooks but in the building code. You may not get electrocuted, but your house might still cause a fire, if it is installed on foundations that don't have sufficient grounding. Get a local electrician who knows the code for steel structures to check if for you. If I had this problem and I lived in an area with frequent thunderstorms, would probably look at the code and then double the required grounding. $\endgroup$
    – CuriousOne
    Mar 8, 2016 at 4:31
  • $\begingroup$ Sure @CuriousOne I will refer to electrician for this matter. Just being skeptical and wanted to double confirm the matter :) $\endgroup$
    – Pet
    Mar 8, 2016 at 4:45

2 Answers 2

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A Faraday cage is made to form an alternate path for electricity to travel from source to ground without travelling through the object inside the cage.

So if the Cage is complete then there is no problem in touching the inner surface. That is why people wear cloths out of metallic mesh which also acts as a Faraday cage (check for EMF shield clothing). But remember the cage should be complete, which means the circuit of the cage should be complete.

David embarks doing his stunt

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  • $\begingroup$ Hi Hari, what do u mean by complete cage? The container indeed has few opening (glass windows and doors) $\endgroup$
    – Pet
    Mar 8, 2016 at 4:17
  • $\begingroup$ Which means the circuit of the cage should be complete. Else the current will chose the other shortest possible path to complete the circuit $\endgroup$
    – hxri
    Mar 8, 2016 at 4:19
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    $\begingroup$ In my scenario, the container is placed on 1 feet high concrete. no parts touching the ground. But the distribution box has a wire to the grounding copper, can it be considered as completed cage? $\endgroup$
    – Pet
    Mar 8, 2016 at 4:21
  • $\begingroup$ Yes it is complete. Also add what you just said to the question to make others understand your question $\endgroup$
    – hxri
    Mar 8, 2016 at 4:23
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Due to the fast transient that a lightning strike presents, there might be resistive and inductive voltage drops in different parts of the container. So don't touch two different parts of the container during lightning strike. If you are actually building this, please also note that you the entire container will be a lightning attractor, so during a thunderstorm, it is very likely that your container actually will be struck. I would not want to be the first person to stand with both feets on that container floor during a lightning strike.

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  • $\begingroup$ Why would the container structure be a "lightning attractor?" $\endgroup$
    – Asher
    Mar 8, 2016 at 12:28
  • $\begingroup$ Because it is a higher point (spatially) at ground potential compared to the ground which it stands on. This means the electrical insulation between the thunder cloud and the ground is weakened at the container. $\endgroup$
    – Skitskraj
    Mar 8, 2016 at 15:00
  • $\begingroup$ I have a vinyl flooring installed on the container floor. And most of the time I will not really touching the wall. I used to get electrocuted when I help holding 2 separate metal bars on my right and left hand (rectangular frame and Im in the middle) and happened that the electric running through my body. Maybe the path is shorter and possibly cause that to happened? $\endgroup$
    – Pet
    Mar 9, 2016 at 2:06
  • $\begingroup$ I just wanted to point out that it is not necessarily safe to touch your container, as some other answers have suggested. Regarding the 2 separate metal bars, you don't provide enough information to know what caused the electric shock. Were the two metal bars connected with a conductor? What was the source of the electricity? $\endgroup$
    – Skitskraj
    Mar 9, 2016 at 5:39
  • $\begingroup$ The "shorter path" that you mention, probably comes from the "current will choose the shortest path" statement. There are two things to note here: the word "shortest" is not meant as the spatially shortest path, it is meant as the path of least resistance for the current. Secondly, the statement is commonly misinterpreted as "if you have two paths of different resistance for the current, all current will take the least resistive path." This is incorrect, the current will distribute between the two paths, in proportion to the resistivity. See e.g. en.wikipedia.org/wiki/Current_divider $\endgroup$
    – Skitskraj
    Mar 9, 2016 at 5:49

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