If anyone is concerned about possibly getting household AC voltages on your wrist strap, consider this:
Standard ESD wrist straps should have a 1 million ohm resistance. If the ground wire were attached directly to 120VAC, you could experience at most 120 microamps of current through your body (and that neglects your resistance, which is usually in the hundreds of thousands of ohms). OSHA claims that most people can't even perceive currents lower than about 1mA, and we're talking about 1/8 of that current here.
If you have a proper wrist strap, then you're very unlikely to electrocute yourself, even if you plug right into the hot line.