WarmFluffyUK posted on Jul 12 2006 at 01:45 AM said:
Okay here's an important a note on safety, not only for you but for your PC too. If you do anything inside your PC, you should do the following. Leave the mains cable plugged in, but switch the power OFF at the mains outlet. Why? Well by doing this you are cutting power from the system making it safe for you, but you're leaving it earthed. So why do you need it earthed? The main reason is to minimise the risk of you zapping components due to static discharge from your body. If you touch the case of your PC when it's earthed, you discharge any large static potential from your body, and it's less likely you can zap any CMOS technology chips, such as the CPU etc. I know that most chips these days have a certain amount of built in safety guards against being zapped, but it's better to be safe than sorry.
Wow, no offense, but that is bad advice for one very big reason:
You're assuming the
outlet is properly grounded(earthed). If it's not, then not only is leaving it plugged in not accomplishing anything to protect the components, but a power strike could come back UP the cable and fry the PC and, if especially unlucky, our fledgling tech.
If you're in the US, a Better way to ground, barring a dedicated grounding mount (generally you've only got one of these if you work on such equipment often and have a dedicated workbench) is to attach a conductive, insulated cable to the grounding screw of the outlet faceplate (the one between the two outlets, usually) and attach that to the chassis of the case via an alligator clip or similar fastener. This way, if the outlet isn't grounded correctly, you may still fry your box, but run far less chance of getting a fatal half-dozen mils across the chest.