How can you locate a Ground Fault break?

A ground fault happens when (usually mains) electricity is conducted outside it's intended path and tries to get to ground by the shortest path. If you touch something 'hot' electrically while you are grounded, or are also touching something that is grounded, you will become that shortest path to ground and will be shocked and possible killed.

A ground fault can occur in normal mains wiring. For example, if a conductor is not properly insulated and it touches another conductor or the conduit it runs through it can can 'short circuit' to ground causing a ground fault.

A ground fault can also occur in a defective or miswired electrical receptacle or appliance.

To find the fault you have to be familiar with wiring for the structure in question, and have to trace the wiring through it's circuit, possibly to the mains connection to the structure.

For example, if you know that certain problem plug receptacles in a particular house are on their own circuit, you can open them and may be able to visually check for shorts and that the wires are connected properly.