I have seen that with a Cousin. Children tend to turn on and turn off switches and knobs of every electricity device available in the household.
Long, long ago I have once read that children's hearing abilities are much, much finder than that of adults, so fine that they are able to hear the sounding of electricity transformers within electric devices. The same source stated that at the beginning of the … electrification, people could hear the humming sounds of transformators several kilometres in the distance and tke this as an indicator to where people live, when they were wandering around.
I don't know if this is true. Even more since I won't ever be able to prove it, since my own hearing ability is somewhat decreased.