Gravels and electricity

Have you ever wondered why the compound of an electrical substation is usually covered with stones or gravel? I have always thought that it is to avoid water retention when it rains. I also know that it has something to do with step potential and earthing resistance. But I also found out that there are more to it.

During rain, water seeps through the gravel and avoids flooding in the substation. (Water and electricity don't really go together!) After rain, the gravel does not allow the soil to dry as sunlight cannot penetrate through. This improves earthing resistance. People in the electrical line knows the importance of low earth resistance in substations.

Of course, the presence of gravel slows weeding. So the gardener need not go into the substation with a lawn mower every month. By the way this is not allowed as we don't want grass to be splattered all over the HV equipment.

But of all, the most interesting bit of info is that gravel helps to deter snakes! Apparently, snakes are attracted to corona sound (that kind of crackling sound you hear sometimes near high voltage lines). Snakes prefer to slither along on smoother surfaces like roads. However, the pointed edges of gravel makes it difficult for the snakes to move - hurts their belly! So gravel is a snake deterrent! Good idea as our technicians wouldn't like to move around in the dark at night with snakes around.