A rule that does not make sense yet
The book says a circuit breaker protects the conductor, not the appliance. I keep mixing this up. Explain it with one simple example and then test me.
Think of the wire as a road with a safe traffic limit. The breaker watches how much current travels on that road. If too much current flows, the wire can heat up, so the breaker opens the circuit. The appliance may have its own protection, but that is a different job. Question 1: A wire is rated for less current than the appliance normally draws. What is the first problem you would expect?
The answer teaches one idea at a time and waits for the learner to respond.
