All homes have circuit breakers or fuses. These are designed to protect the wiring and appliances within your home, but they may not work quickly enough to save a life.

They cut the power instantly - before you even know that you're in danger.
All it takes is a faulty appliance or power tool, amateur electrical work, clumsy home handywork or a curious child playing with a powerpoint to be a victim of electrocution.
It's faily easy to tell if you do have a safety switch. Take a look at your switchboard (usually where the meter is) and look for a switch with a "Test" button next to it (similiar to the one in the picture above). If you do have one, check that it works properly by pressing the test button - the adjacent switch should turn off. To reset, simply turn the switch back to the on position. Tests should be done monthly.
Your home may already be protected - If you don't know or are not sure, ask your licensed electrical contractor.
Take care doing home handiwork - do you really know what's behind the wall you're about to drill into?
Article sourced from the Queensland Electrical Safety Office.