Roll Cage or Faraday Cage

[captainhaddock]

So, according to an article in the Express " DRIVERS travelling in convertibles ‘could be in trouble’ during lightning strikes and thunderstorms this weekend".

https://www.express.co.uk/life-style/cars/1470467/convertible-drivers-thunderstorm-lightning-strikes-road-safety-weather

It goes on to say convertibles “don’t have a complete metal structure” meaning drivers may not have sufficient protection in storms. Ordinary cars are fitted with a metal structure that sends electricity “around the outside of the vehicle”.
“If a car is struck by lightning the metal structure acts like a Faraday cage.
“But if you are driving a convertible, even if you have the roof up you don’t have a complete metal structure surrounding you and that means you could be in trouble.”

Should we be shocked at this revelation!

[ast]

BMW convertible hit by lightning in 2014

[McTrucky]

■■■! Must remember to always get in a cage before going outside unless I am in a car with a roof…

[Enjoyabull]

Well that should be taken with a pinch of salt, it is called a Faraday Cage because it is a cage and not a box, so has holes in it.
Should you get struck by lightening and it happens to hit the part of the car you are sat in, a modern car roof will not help you any more than a soft top with a steel frame holding it over your head. Oh a bit like a cage.

P.S. Low profile tyres increase the risk.

[TerryM1]

Well, I’m 70, had a good life and the kids are all set up nicely. The missus has preceded me into the afterlife so I’m basically just a waste of resources now. I can think of worse ways of going than in a massive flash and bang at the wheel of my 5 .

[John_Aston]

I have a very healthy respect (and that is an understatement) for lightning , having been caught out several times while fishing in remote spots. Never been more frightened than the time I was on a wild loch in Wester Ross, two hours walk from my cottage with no cover anywhere. And don’t ask me about British GP weekend 1975. Shudder.

Mercedes made a thing about lightning protection in its convertibles a few years ago , designing in Faraday cage protection to its drop tops . Normal hard top cars tend to be ok - Tomorrow’s World did an experiment with a Sierra at a Siemens lab , where artificial lightning was created and the car struck, repeatedly . Driver and car were fine- the only effect was that the rear wiper gave a single sweep every hit .

[First_rider_off]

Yeh, but the soft top is untouched Seriously I would think that the lightning would travel to earth through the least resistive route which is the car (metal) bodywork. Perhaps another argument for not replacing the “lightning conductor” standard aerial with a stubby one What about fibreglass cars? Are they thought to be extra hazardous in a lightning storm?

[McTrucky]

The solution is simple. Next time you are driving in a storm, just stop, ask your passenger to get out and stand next to the car. They will be taller than the car so lighting should hit them and not the car, thus protecting your paintwork.

Maybe as a seemingly nice gesture of kindness to them you could provide them with an umbrella, but the actual reason would be to ensure additional height and conductivity, just don’t tell them that.

The flaw here may be that you do need to stop, unless you also provide a skateboard and some form of attachment to you car (be careful of scratches though).

[ast]

Statistics on lightning strikes on cars are, naturally, hard to find.

The best (best being 5 minutes on Google) I could find was a paper presented by Ronald Holle “LIGHTNING-CAUSED DEATHS AND INJURIES IN THE VICINITY OF VEHICLES”

These represent a period 1991-1994, US data gathered by NOAA. Now, it might not record all the possible incidents, as I suspect most go unreported, or unobserved.

Now a non-enclosed vehicle is anything without aroof, such as a bulldozer, someone standing in the back of a truck, a TV cameraman on the roof of a vehicle, a soldier on a AFV, pushing a wheelbarrow, operating a golf cart, someone pouring cement from a mixer. Of the incidents listed, only 1 includes “an open top recreational vehicle”.

We can’t use these stats to conclude 0.95% of vehicle strikes involve a convertible. We really need to get into strikes per incident, or rate per car journey. Tintops, on average, are used a lot more, and are used all year round. Convertibles are used used less frequently, often not used all year round, are less likely to be used in adverse weather, so its possible that a convertible is more at risk of being hit by lightning that a tin top. Or not.

But we could infer that probably these incidents, overall, are quite rare. The various TV show demonstrations can be shown to be red herrings, in that cars can be damaged, in quite dramatic ways, by lightning, and its quite possible a strike might write the car off (eg random gouges and burns through several panels).

We might also infer, with care, the chances of injury. Crudely, if you are in a convertible, and are hit by lightning, you have a 19.6% chance of being killed. That compare to 4.9% in a tintop. And it seems that you are twice as likely to be injured in a convertible. But this is from a small sampling, and “non-enclosed” has a broad meaning, though materially, sitting at the controls of a bulldozer isn’t so different as being in a MX5. Also, Table 6 goes into some detail for tin top cases, and clearly, not everyone was actually in the car when hit. Notably, several deaths while attempting to close windows.

http://lightningsafety.com/nlsi_pls/lightning-caused-deaths-around-vehicles.pdf

[First_rider_off]

It’s obvious as shown in Saz’s pictorial example earlier. God does not like BMWs, but he loves MX5s so don’t worry about it.

[as400]

Sorted.

[Smurf1]

Old golfer theory is you just need to hold up a 1 iron and you’ll be fine…

…not even God can hit a 1 iron

[RichardFX]

@Smurf1

…not even God can hit a 1 iron

But, very sadly, I have seen him hit an innocent driver.

February 1965, Mount Pleasant, Salisbury, Rhodesia.
One of the caddies for the twosome ahead of us had fished a ball out of the pond next to the green they had just left. We waited until he was clear and on the elevated next tee before playing our shots to the green.
His trainers were hanging around his neck and while we walked up I saw him take a driver out of the bag, extending it over his head. I assume he still had damp hands and wet bare feet.
A sharp fizzing noise followed by a blinding flash and the loudest bang I have ever heard and there was a deep hole in the tee where he and bag had been.
It was utterly horrific.
I can still see it now, by far my worst ever memory.
All that was left was his trainers and a burnt cooking stink. The two golfers and the other caddie were blown off the tee and quite badly singed but otherwise OK.

I gave up golf very soon after that.

[John_Aston]

Bloody hell .

[999to5]

We arrived on the small Croatian island of Vrgada the day after a tragic incident.
A Swiss tourist on an island hopping kayak tour had got up in the night to have a pee. No facilities, so he stood on a rock to pee in the sea when there was a lightning strike.
Apparently, he looked relatively unmarked externally but all his organs were fried.

[Smurf1]

Yikes.
I grew up in Johannesburg and played golf in my early teens, sirens would sound around the course to warn of lightning risk and everyone basically ran to the clubhouse

[McTrucky]

I attended the health and safety course on electricity at work and it was explained that electricity flows better through liquids (such as bodily fluids) than it does over dry skin.

So quite common to have burn holes in and out through skin with no other extremal damage, but inside is cooked.

Also, when you heat liquid rapidly it boils and you can get an explosion like a steam boiler going off. We had to look at pictures of legs literally burst open.

Most memorable training I have been on…

[TMW]

I’m sure that the well known editorial factual standards of the express combined with comments from a car leasing firm are a very credible source of of course the physics of a lightning strike path…!

[RichardFX]

No warning. The mid-morning sky was almost clear, it struck out of the blue, but half an hour later the rain was pelting down, a couple of hours earlier than usual.

It normally rained from shortly after midday for anything from ten minutes up to an hour or two. You could look at the sky and estimate reasonably accurately how long you had to cycle home from school for lunch before being soaked. Sometimes it was a race to escape from a wall of water marching along the road behind you, and the route home had some zigs and zags to be caught in.

The hole in the ground on that tee was deep enough and wide enough I could have stood in it and not seen out over the top. The ground around it was still hot while we were giving first aid, lots of water in our hats from the pond to cool the burns.

And yes, we then all sprinted to the club house, leaving bags of clubs etc behind. Alas, it was only a new course and no thoughts of a siren, and none of the newly planted trees had any height to divert strikes. Now it is scrub and small allotments.

I’ve failed to grab a screen shot off the satpic, however, the co-ordinates for the old clubhouse at the end of a short stub of track on Googlemaps are -17.77155114678867, 31.067500411410318