Ground Wire Material

What type of guage wire should I run from my main panel to my cold water connection? Someone said it should be insulated wire others said uninsulated (bare copper)?
Don't bother. Most pipes have some type of thread sealant applied between the joints (teflon tape, pipe dope, etc..). In effect, you might connect to the water pipe but how far that travels into the "ground" might be another story. Besides that, if your electrical ground is in another area of the yard, the difference between ground conductivity could create a ground loop and give you all kinds of hum or buzz problems or even result in what is known as a "hot chassis". Skip the "makeshift" installation and have an electrician run you a dedicated line. WELL worth it and much safer overall. Sean >
Uh, if you are talking about your main breaker panel, then you should be talking to your local city electrical inspectors. Not us. Not even an electrician.
Generally, heavy gauge multiple-strand bare copper is used. In newer homes, most water supply is copper with soldered joints. This is even used by licensed electricians following local code and subject to inspection. In any case, the good point made is to either have a locally licensed electrician do the work or know your local code and have it inspected.