Now, this is not true for all towns. After all, Australia was not exactly settled at the same rate. However, around 42% of NSW homes, for instance, were built prior to the start of the 20th century. Of course, the electrical infrastructure of these dwellings is newer than this. But even so, around one in three Aussie homes is more than 40 years old, and for these houses, their electrical systems were mostly built before safety switches were required during construction.