I too have noticed this problem. The generators just stop sending power sometimes when I first load the game. It happens sometimes with some solar gens, but mostly it happens with a Geo Gen. I have a nether portal next to my geo gen for a quick lava resource. I am able to "restart" the generators by going into the nether and the coming back to the overworld. I never tried just replacing the cables, probably would be faster and easier than the nether trick.