Differentiate between a class 1 circuit and power supply circuits (lighting,receptacles, etc).I am still having difficulty looking at a system and making the determination "This is a class 1 circuit". Is there a simple set of criteria by which a person can apply and make a precise judgement?
Read the definitions in Article 725, and then read about the power source in Part II and Part III. This should help you with your understanding of the terms a little.