# Can wrist strap be attached to running PC?

Sorry if this is a noob question... I've Googled for instructions on how to use a wrist strap, but most of the answers I've seen assume that you're going to be opening up your PC and installing or working with boards in it, so they all say to turn off the power and attach the strap to the PC case. My situation is that we have a separate board that will be connected to the PC via a USB, but I will not be opening up the PC and don't plan to turn it off. I still want to prevent ESD damage to the board. Is it still OK to attach the wrist strap to the PC case (say, to a screw on the back) while the PC is on? Or am I risking injury? (More info: This is in an office building, recent construction, 2nd floor, all carpeted, boss would prefer not to shell out money for a mat.)

• I placed a carbonized mat under keyboards, so carpet/chair static wouldn't zap the system. Anyone reaching for the keyboard would make first contact with the mat, discharging the static, and solving that issue. Nov 9 '13 at 19:12

As long as you have the proper type of strap you will be safe. ESD (dissipative) straps have a large resistance (~ 1 M$\Omega$) in series so that in the chance that the person gets shorted out that they do not end up being wired into mains voltages. The concern here isn't for the ESD , any form of conduction will solve your ESD problems, the concern is for safety. If your boss won't shell out for a mat, just make sure he hasn't cheaped out on the wrist strap too to save a few pennies.!