It is difficult for students to understand how electric circuits function. The processes involved are invisible because they occur at the atomic level and thus are abstract in nature. Electricity can not be felt with using the personal senses (unless we receive an electric which is certainly unwanted), electricity cannot be manipulated directly, and what is happening is thus not readily apparent.
The circuit breaker will open, or "break", the circuit when the current in that circuit becomes too high, or the fuse will "blow". This gives protection.
One way to make this topic more accessible is to use analogies (Lakoff and Johnson 2008). Analogies are examples which possess similar features, or work in a comparable manner, to the ideas that you wish to teach (Harrison and Coll 2007). They offer an excellent method of visualising difficult and unfamiliar concepts, or ideas that can not be directly seen.
A schematic is a diagram of an electrical circuit. Schematics are graphical representations of the essential connections in a circuit, but they are not life-like depictions of a circuit.