I would like to know how to properly use an antistatic wrist strap.
By antistatic wrist strap I mean a band with a wire attached to it, with a metal clip on the end of the wire.
From what I read about them they really do help prevent harmful static discharge. However, it isn't clear to me what to connect the wrist strap to. Obviously one end goes around the wrist, the other is clipped to the ground. But what exactly is the ground?
Does it work to connect it to:
- … the case of the pc, while the power plug is still connected to the case, but the switch on the back of the PC is off. To me this seems risky, since it's difficult to guarantee the components of the PC are truly powered down.
- … the case of the PC while the case is NOT connected to anything. There is no grounding to the actual earth in this case.
- … the plumbing in my house, meaning radiators or metal piping. This doesn't seem like the ideal grounding to me, since the static charge on the plumbing could still differ from the charge of the computer case. Right?
- … any large metal object, not connected to anything. It would just lose static to the air over a large surface area?
In all these cases I would of course not connect to a painted surface, since the paint might isolate rather than conduct the static electricity.
Additionally, is one wrist strap sufficient when working with both hands? Does the wristband drain the static on my other hand as well? (Sometimes a component is stuck, and may require two hands to pull it out.)
And what do I ground myself to when I am working on separate electronic components? For example; cleaning my graphics card while it is not in my computer case?
And finally, does a good anti-static wrist strap need a resistor? And if so, how much resistance should it offer?