Sort of a silly question..but does your box have to be plugged in for your anti- static wristband to work if it's clamped to your case? I don't see any ground happening otherwise, but I don't really understand electricity. And other than having the box plugged in, could I use a small wire soldered to my sprinkler or water pipes, to which the wristband is attached?
The idea is that the current will pass from your body into the case via the wrist band rather then into your devices. So long as the wrist band is connected to the metal of your case.. you're grounded to the case.
Do not attach the wrist band to any components that make direct contact with a part of your PC (save for teh case that makes contact with the motherboard but which is grounded as well).