Earthing & System Grounding

<...provide protection against indirect lightning surge?...>

Overhead telegraph wires used to have surge arrestors installed between line and ground so as to provide a discharge path for high voltages that appear on the line. From memory, these were a small glass discharge tube fitted with two electrodes, each one with a connection lug outside it. The lugs bolt onto a terminal block, with the earth connection one side and the lines' connections the other.

The other technique used to protect things is the common-or-garden lightning spike, fixed to the top of a tall structure such as a mast or a tall chimney. The technique involves attracting the lightning preferentially to that spike and then to earth, thereby reducing the risk of its striking adjacent structures.