tracing hiden electrical wire

The wiring in my house seems to have been done by a drunk. The materials are ok but the polarity is random and the central grounds are not connected though present in the wire used.
I would like to correct the polarity and properly attach all the central grounds. I will also be running seperate circuits for refrigerator etc as well as to kitchen with GFI's.
I have seen computer network people inject a signal into a wire and follow it all over a building. I would like to be able to do this and beleive it would make the project simpler.
When I was young my father did something simular with a cd radio. Is there any way to do this without buying lots of expensive equipment.
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