One of these damp-proofing methods that was sold and installed by Rentokil in the 1970’s was an electro-osmotic system that used a copper wire embedded in the wall and then an electrical charge was put through it in the theory the water would be dispersed. It never succeeded although many were installed and can still be found today.
You can see it in these pictures and the two internal walls show the copper having completely corroded to powder. Copper corrodes when in contact with cement and the cables were always pointed in the brickwork with a cement mortar. It was destined to fail from the day it was installed.