Nickel Plating Handbook [pdf]

Would using Nickel plated copper wire help prevent galvanic corrosion of carbon steel when grounding a fence using copper wire? Or would the copper coated with Nickel still act as a cathode making the fence anode??

What happens when there are small areas where the coating has worn through?

Nickel is almost as noble as copper, so it would not change anything.

For the galvanic protection of steel, like in marine ships, electrodes of zinc, or better of magnesium, are suitable.