I`m not quite sure where you are going with this.
If you are working inside your PC, it should always be with the mains power switched off. You can then ensure you are at the same potential as the PC by touching the chassis (NOT a HDD or component) before doing anything else.
If you are one of those who has a static charge problem, you can buy a wrist strap similar to click here to connect to the chassis whilst working on the PC. This will permit any charge to `leak` slowly and prevent any risk.