What is this extra wire that was connected to my water heater?

Question

I replaced my electric water heater recently, and there was an extra, solid copper wire that was clamped to the top of the water heater where the cold water pipe enters the water heater. This wire goes into the wall where the metal-sheathed electrial line supplies the power to the water heater. My water piping is quest, so I don't think it was an attempt to ground, but I'm not sure. For now I have this extra wire just coming out of the wall, attached to nothing.

Answer 1

It's supposed to be a ground wire, but sounds like it's not really grounded.  If you want to actually ground the wire, drill a small hole through the basement wall, probably with a cement drill and drive a small copper rod through the hole into the dirt.  That's all a ground is.  Attach the wire to the ground rod and you're home free.  

Answer 2

its a ground wire

Answer 3

I believe this is the anode rod connection. The magnesium anode rod  in water heaters is designed to protect the inner steel tank against corrosion

Answer 4

It's a ground wire.  The plumber that installed the water heater was probably just following the directions on how to install.  Try to ground it to something else.

Answer 5

Attached by wire to any metal s***w in the hot water heaters jacket.  The bare copper wire is a frame ground.  Its purpose is to keep someone from getting shocked when working around the water heater.