Lighting Storms and Vandwelling safety

[Almost There]

Not an expert either, but my limited understanding is that Faraday cages must wrap completely around you in all directions.  If any area is open, they don't function as a Faraday cage.

How open is considered 'open' so as to not function properly?

My van has only the middle 6' cut out of the original roof but that area has 1/4" x 2" steel cage that reinforces the fiberglass roof and is welded to the inside edge of the original roof.  I'm sure it was put in for roll cage safety but does it also function as a complete Faraday cage?

 

[ArtW]

I'm interested in the answer to that, too, since a car body is not actually fully enclosed, it has all these things like windows and such, which would seem to argue against either the car being a faraday cage, or against the requirement that said cage need be fully enclosed

 

[TrainChaser]

bLEEp: "So the lightning will actually penetrate the fiberglass high top and not be attracted to the remainder of the metal box we are sitting in?"

I'm sure they're talking about a direct hit, or where the lightning 'jumps' off another object.  A direct hit must be a real blast of power.

I just looked it up:  "An average bolt of lightning, striking from cloud to ground, contains roughly one billion (1,000,000,000) joules of energy." From http://www.realclearscience.com/blog/2012/05/could-we-harness-lightning-as-an-energy-source.html

That seems like a lot of energy to hit one spot all at once.  I can see that a fiberglass top could have trouble dealing with it.  I guess it might really pay to carefully consider your parking spot when a storm comes up.

Here's a recent article, "What Happens When Lightning Hits Your Car?"  https://weather.com/storms/tornado/news/what-happens-when-lightning-hits-car-20140625  It does mention non-metal body shell parts.

 

[Optimistic Paranoid]

I do not know the answers to any of the questions asked above.  The Wikipedia article on Faraday cages suggests that it's effectiveness depends on:

A:  if the conductor is thick enough, and

B:  any holes are significantly smaller than the WAVELENGTH of the radiation you are trying to shield against.

Clearly, the gaps left by windows don't cause a problem with it's effectiveness against lightning.  Wonder if Lightning has a wavelength?  If it's DC electricity, the answer is no.

OK, I just googled that and found the following answer:

"Initially it is DC with an extremely fast rise time which gives it a high frequency AC component at the initial strike.  Once the arc is established, it contains all frequencies in the RF spectrum which makes it AC."

This RV site:

http://www.craigsmithrv.com/custompage.asp?pg=lightning-stikes-rv

suggests that if your RV has a steel or aluminum frame, you're safe even if the skin is fiberglass.  However, if the frame is wood, you're screwed.

Almost There, sounds like you might be OK.

 

[TrainChaser]

Suppose you have a ladder rack attached to the sides of a van, held above the fiberglass shell???

Jeeeeez! You have to be a scientist to figure out what kind of van to buy! *whine, whine*

 

[Wanderer]

Iowa 1996 Straight line windstorm came through...lighting dropping every half second...35 minutes of me and roommate in basement in shorts and not looking at each other  

2007 Cabool, MO and after 3 days of storms road to one town blocked by water 15 FEET over low bridge they had...

Crazy fun....

 

[ccbreder]

I had a house in a wooded area. Lightening struck a tree in the back part. The tree exploded into wood splinters the size of kindling. The wood was in a circle of 20 feet from the original tree. A neighbor came into our property and took most of the larger hunks of the trunk. Their stove malfunctioned that winter and burned the wall out of their home.