Grounding and Static

[aidanjt]

Biggest load of rubbish i ever herd!
It's you feet rubbing on the nylon carpet/mat!
The car chassis is connected to DC negetive from the battery so it is effectivly grounded!

You mean the feet with shoes which have insulated (rubber or leather) soles rubbing off the nylon matt?.. It's more like the friction between the clothes and the seat. And no, grounding the chassis to the battery would be a *bad* idea, cars used to be grounded by a strip at the rear of the car, these days it's done through the wheels with small traces of metal oxide part of the compound, but there's still small residual build-up, that's why you can get a bit of a shock on some cars, especially after a lengthy journey. But that aside, the human body makes for a poor conductor, the charge can go either way depending on the electrical potentials.

[Thorsson]

So is the moral of the story, "Don't build your PC in a moving car"?

[aidanjt]

lol, pretty much.

[Andy3536]

You mean the feet with shoes which have insulated (rubber or leather) soles rubbing off the nylon matt?.. It's more like the friction between the clothes and the seat. And no, grounding the chassis to the battery would be a *bad* idea, cars used to be grounded by a strip at the rear of the car, these days it's done through the wheels with small traces of metal oxide part of the compound, but there's still small residual build-up, that's why you can get a bit of a shock on some cars, especially after a lengthy journey. But that aside, the human body makes for a poor conductor, the charge can go either way depending on the electrical potentials.

It's still done, my Mums car needed starting about 4 weeks ago and the guy from the AA placed the Negative lead on the left wing body pannel.
Battery negative is used as when a component in an electrical item goes short instead of going to earth in the mains it goes to the chassis and through the tyes to ground. They need to have electrical safty on cars aswell you know!
Trust me, when you get a shock getting out of a car it is static charge going from you to a car. Thats why you'll see some people will be effected alot more than others, because of the coat, jumper they are wearing.
The human body is not a great conductor but static electricity works in a different way to ac or dc.

[Andy3536]

Theres a wonderfull thing about the internet, when your right you have google on your side
http://homepages.pavilion.co.uk/jeremys/home.htm
Those 3 qualifications in electronics wern't wasted after all!

"One problem that is often experienced is that when you get out of the car, you get a shock on touching the door to close it. The source is usually static charges which build up between your body and the car seat while you are in the seat, but remain harmlessly neutralised until you get up."

[Agent]

1. Don't build a pc in very hot, dry weather where your constantly zapping things.

"very hot and dry" are entirely subjective. I guess this means that our friends in Oz are screwed then
Temperate does make a difference to the way electrons move, but there still needs to be an electrical difference in charge between two objects.
You generally find that the potential difference between objects stay the same if they are both increased in temperature by the same amount. For something on this scale though, its practically redundant (the equipment needed to measure the potential difference between you and your PC case isn't easy to come by )

2. Don't shuffle your feet across the carpet. PICK UP YOUR FEET!

Can PC parts be damaged by static electricity? Totally, there is no debate on that.
The amount needed to actually cause the damage? - very very unlikely to come from a person building a PC using their brain.
Remember, you need to have a reason for the static to build up. Even dragging your feet over carpets causes a fairly small electrical charge. As soon as you touch the case - 'problem' gone.

Straps don't get 'rid' of static electricity, they just cause any build up in the difference of electrons in you and the object its attached to happening. In theory, if this object is earthed, so are you.
In practice, building up enough electrical difference in you and parts you are dealing with after touching the case is on the microscopic level. You can't ever stop the flow of differently charged electrons happening in situations like this.

3. Be in bare feet.

Thats brilliant
Being bare-feet certainly won't stop a differing electrical potential difference from happening.

4. Keep unused hardware in the baggies.

This is worth doing simply because its safer.
You'll damage your hardware by an accidental knock or bump way before static will.

5. The most important tip ever: touch the metal case to get rid of that electricity every time you wak away from your spot where your working.

Covered above I think
When I was at college many years ago, we had a fair bit of conversation about this in our Physics class. To cut along story short, we tried to kill a Voodoo Rush (IIRC) card with a Van de Graaff (sp?) Generator.
We did kill it, but not on the first go

Short version: Install your PSU, plug it in and its earthed. Touch the case every now and again and thats it. Any more is simply an overkill. You aint building a Mars rover for Nasa here

Hope that helps