I have an older house in which the electric cables to all the switches and receptacles have only 2 wires: one black (hot) and one white (neutral). I would like to upgrade the receptacles to the newer type that have a third opening in them for a ground. I would like to avoid running new cable with three wires (black, white, ground) as this would be a fairly tough job to fish new cable through the walls. The new cable is also pretty expensive.
Is it acceptable to just run a ground wire (either bare or green) from the ground bar in by service panel to the receptacles. In many locations this would be easier than fishing a whole new cable as well as less expensive.
Thanks in advance for any guidance.
Herb