Circuit Inspection Tools

I accidentally stuck a finger in an outlet while sleeping when I was around 8. My bed was on a wall with the outlet and my hand rolled off the bed.

impedance between what? how are you measuring this?

When my amprobe INSP-3 worked it gave me this information when testing a circuit. That is the primary reason I would use it. I would use it when inspecting a house that was built before the ground wire requirement that has three prong outlets.