I'm shocked!

I have a 2010 Subaru Forester that shocks me when I get out of the car. Not all the time. It’s worse in hot weather, but today is windy and it’s happening again. I have to close the door with my sleeve. I’ve never had a car that did this before. More than once I heard you say that it has something to do with the tires and it can be remedied by installing a ground strap or strip, but no one seems to know what that is - not the dealer or several people at numerous parts stores. What does this thing look like, where does it go, and why is it such a super secret device that no one but you knows about it? Barring that I’m going to assume you sent me on a snipe hunt. Any hints gratefully accepted.

It is for real. They used to be quite common on cars a couple of generations ago, but I haven’t seen any in a long time. Here’s a sample available at eBay:

For $9 it is probably worth it to you.

There’s a very good reason those are hard to find: You shouldn’t use them. They used to be available everywhere…but not anymore.

You car is an electrically isolated being, and in storms (think lightning), it will shield you completely if hit. The tires keep you separated from ground. People have actually (cases not handy at the moment) been seriously hurt or killed by electricity going through the chassis, where it’s normally a very safe place to be during a storm.

You have another problem, and finding it should be the priority, not figuring out a way to just pretend it doesn’t exist.

The problem is in your pants and shoes. When you slide out of the seat, you build up static electricity on you. When you touch the car, you ground yourself and get a shock.

If you didn’t wear shoes, you would not get shocked. There are shoes made for the electronics industry called ESD safe shoes that will also keep you from getting shocked, but most of those are also steel toed shoes or boots.

If you hold onto the door of the car, or any part or the car as you get out of the seat, you also will not get shocked. If you get out without holding onto a metal part of the car, you can avoid the shock by touching the car with a key or coin. You technically get the shock, but it is spread over a wide area of skin so you don’t feel it. The arc occurs between the key or coin and the car and not to your skin. Its not the shock that stings, its the arc.

Note: if you use the key, you must be holding onto the metal part of the key before you touch the car body.

I’ve got one car that I get static shocks from as the weather cools. I just ground my arm on the car door when I get out to discharge the static-especially at the gas station. Its the seat fabric I think.

All of the above.  I will add that different fabrics (what you are wearing and what the car seats are made of) make a big difference.  If you like polyester fabrics, you will have more problems.  

 You can buy anti-atatic spays that should help as well. (see your local computer store.

 Most newer cars have less of a problem, but still some fabrics used in today's cars can still cause problems.

There was a good discussion on this last year, talking about how the tire compound is related. See:


Note CapriRacer’s comments.

chaissos - It is not the tires that protect you in an electrical storm. It is the metal chassis.
It routes the current from the lightening bolt around you. To complete the circuit to ground, the current must arc through the tires. You would actually be better off in a lightening strike to be riding on the rims. A ground strap is perfectly safe.

Phillip: That phenomenon is known as a “Faraday Cage”, but it’s wrong, too. You have to be mindful of not touching anything metal, and to save the car, you should shut everything down an park it to wait out the storm. Having the car isolated from ground can make your car a less viable target. Having grounding straps just makes it more likely you’ll get hit, as you’re making yourself a moving lightning rod. Been there, done that, more than once. Still have the unmarred vehicle.

Didn’t see you link until after I posted…I don’t get the CSS stylesheets on this connection. this site is just a lot of text for me.

Just curious – has anyone ever heard of a single case in which the occupant of a vehicle was injured by lightning?

No, but on an episode of Top Gear one of the hosts (Richard Hammond) went to an electrical lab in Germany and participated in a test of homemade lightning on an automobile.

He took his place inside the car and the technician at the controls gradually stepped the voltage up until lightning started arcing into the roof of the car. Neither occupant or car was damaged.
It was a pretty stunning demonstration to watch and while I don’t remember the voltage level I think they had it cranked up to around 800,000 or so and the arc was kept in place for a fair amount of time. It wasn’t a one second and done deal.

chaissos - After the lightning bolt travels through thousands of feet of air, six inches of rubber tire laced with metal belts is not going to impede it even a little. You are dealing with millions of volts, here.

Friends of mine were putting up a tarp with metal poles and lightning struck a tree 50 feet away from them. They felt nothing. Being the highest object around makes it more likely that
you will attract a bolt. I was there. It was LOUD!

No one has been hurt when lightning strikes aircraft. It is a fairly common occurrence.

Staying away from metal objects in the vehicle may give you a little added protection, but in general the metal body of the car is going to be a far better conductor than you are. It’s just a simple thing to do, so stay away from the metal.

These ground straps are not solid metal. They probably have a couple 100 ohms of resistance. That is sufficient to discharge static electricity. There is very little current, but
high voltage.

The bottom line is that you are in no more danger from lightning when you have one of these
ground straps attached to your car.

SteveF: There are lots of reports of police being hurt in vehicles, a simple google search will reveal lots of them. There are reports of officers being hit through the radio handset, too. So yes, not touching anything metal does have a great impact.

Regardless of how you look at those stupid straps, they’re useless unless you’re stopped. They’ll drag and get worn when you drive around, a bit of wind will keep them off the ground, and it doesn’t take very long at all for them to be too short even when stopped. I tried them, they were pointless, and after about two months (that’s how long they were long enough to touch the ground), I simply threw them away. They’re as much of a pointless gadget as the thing you plug in your cigarette lighter to improve your mileage. If you want to use them, go right ahead - it’s your money. There’s just no point.

This is just the excuse you need to wear jeans all the time. Cotton is less likely to charge up than a synthetic fabric.