This is a follow-up to this question.
I am adding (outlets) on to a 2-wire 12AWG (no ground) circuit and I want the new outlets grounded. Can I run a ground wire to the panel along the outside of the house? Obviously it is at greater risk of corrosion and damage than a wire run internally, but this is my only choice (other than leaving the outlets ungrounded). It seems like most ground wires I have seen from the panel to the ground rod are usually un-shielded and un-armored, but are heavy gauge and short runs.
I am thinking maybe a 10- or 8-AWG bare wire run under the eaves would be the easiest/best (however ugly) solution. Total run would be about 30 feet. All suggestions, warnings, or scoldings are welcome.