Jim, some of the old houses I deal with, use a small(16 gauge?) bare copper wire that runs throughout the house, "connected" to the boxes by wrapping several turns around a nail that attaches the box to the stud. The wire would terminate at a water pipe with a strap. The wire is tee tapped, by wrapping the tap around the main wire and soldering, just like knob and tube wiring. Sometimes it's just the kitchen and bath that have the wire.
