ECN Forum Forums General Topics of the Trade General Discussion Area Static Question

Can Anyone easily explain how and why static builds up on someone in a car or truck?

I have wondered why I get a shock sometimes getting out of the vehicle. I never really thought much about it. Today after getting gas (self serve) I got back into the van and started to drive away, looked in the mirror and saw that I had left cap off and door open (mind was elsewhere I guess). I stopped and got out to put the cap on and got a nice shock when putting the cap on (touched metal somewhere). Having a spark in front of the entrance to my gastank really caught my attention.

Anyone know of a way to keep this from happening?

I've always wondered how to prevent it to. What keeps the static down on me is those fabric softener/ static stopping sheets for the dryer.

Had an electrician working for me years ago that screwed some jack chain to the rear bumper so it draged on the ground and it stoped him from getting a shock everytime he got out of the van. After time the part of the chain that touched the ground would wear down and he would start getting shocked again so he just added a few fresh links to the end.

Dave T.

Had an electrician working for me years ago that screwed some jack chain to the rear bumper so it draged on the ground and it stoped him from getting a shock everytime he got out of the van. After time the part of the chain that touched the ground would wear down and he would start getting shocked again so he just added a few fresh links to the end.

Dave T.

I guess that the thing that surprises me the most is that I only drove 5 feet. The charge built up in a matter of seconds. I will surely be more careful next time I get gas!

I'm wondering, is this part of the reason that some states do not allow self serve pumps at Gas stations?

In my opinion most of the static charge builds up between your outer clothing and the seat covers as you slide in or out. If you hold on some bare metal(painted metal is an insulator) on the vehicle as you are getting in or out the charge will be dicharged and no spark will be produced.
In my opinion most of the static charge builds up between your outer clothing and the seat covers as you slide in or out. If you hold on some bare metal(painted metal is an insulator) on the vehicle as you are getting in or out the charge will be discharged and no spark will be produced.
The heat energy is not normally high enough to ignite gasoline vapors, but it is possible. If it did all you would get is a small flash as the vapors around the fill tube burned off. The flame will NOT travel into the tank(the mixture is well above UEL(upper explosive or flammable limit) and it will NOT explode.
Don(resqcapt19)

Here are a couple of sites to look at:

This one is a statement from the American Petroleum Institute about static and filling gas tanks. http://www.api.org/apireports/static.htm

This one is some general static electricity information with a section on cars. http://www.eskimo.com/~billb/emotor/zapped.html
Don(resqcapt19)

Don,

Thanks for the comments. It makes me feel better!! I do usually touch metal when getting out, though not purposely. I will try to do it all the time now though just to be on the safe side.

Don hit the nail on the head!
When you slide across the car seat, you scrape up free electrons from the seat. If you do not ground your self while sliding, the charges build up in your body rapidly, which accumulate to create a large potential [voltage]. The car body is considered ground in this instance, however an actual ground connection is rarely required to discharge static charges [just scrape your feet on a carpet when the weather is prone to static, then touch another person. This should demonstrate this point!!].


Scott.

Don,

Those were good Links! Upon reading some of the information it seems that static electricity can also be built up from simply sitting on a plastic seat (mine are fabric though) and it might have been lucky that the spark happened after some of the fumes had cleared. I will add some of this info to one of the safety areas soon.

Bill