WARNING: working with electricity is dangerous. If you don't know what you are doing, don't do it. I am not responsible if you get electricuted, etc, etc.
OK, now that the disclamer is out of the way:
If these two access points are close (within 3-4 feet) then there is no problem. Most multimeters have a continuity tester built in. Just put one probe on the pipe and the other on the rod and see if the multimeter beeps (signifies continuity).
If they are further away then it may be a little more difficult. There are several pretty convoluted ways you can tell if you have ground but they won't tell the path of the ground. An example is to plug a lamp into the wall using bare wires plugged into the positive and ground holes of the outlet. However, a much safer way is to use a special tester plug (probably about $15 at Home Depot) which has lights signifying ground and polarity. The ground and neutral may be tied together at several spots in the electrical path (and should be terminated on the same electrical bus-bar in the master electrical panel) so there is no easy way that I know of to tell if the current is actually flowing to ground or neutral. Electricity will always take the path of least resistance but corrosion, breakage, temporary fixes that become permanent, etc. can alter this path over time.
Best of luck.
Julian
www.sedonaskysound.com
