The short circuit case is easy to detect with an electromagnet that will have a strong magnetic field when so much current flows. However, the overload case isn’t that abrupt.

I came to engineering by way of the technician route. I learned electronics in a technical school and was taught that current flow was electron flow and all circuit analysis was done that way.

Many introductory books on electricity try to relate voltage to water pressure, electric current to water flow, and resistance to changes in pipe volume.

Learn about the roles of each component in an electrical circuit with these interactive learning resources for KS2 Science students aged 7-11 from BBC Bitesize.