What term is used for mandatory rules in the NEC characterized by the use of the word "shall"?

The term used in the National Electrical Code (NEC) for mandatory rules characterized by the use of the word "shall" is known as mandatory regulations. In the NEC, whenever "shall" is used, it indicates a requirement that must be followed, meaning these provisions are not optional; compliance is necessary for ensuring safety and proper installation practices.

Understanding this distinction is important because it clarifies what is legally enforceable and what is merely suggested or recommended. Other terms like informational notes and advisory notes provide guidance or clarification but do not impose a requirement. Knowing how to identify and apply mandatory regulations ensures that electrical work adheres to legal standards and promotes safety in electrical installations.