Article 424 is a nine-part article on fixed electric space heating. Why so much text for what seems to be a simple application? The answer is that Art. 424 covers a variety of applications — heaters come in various configurations for various uses. Not all of these parts are for the electrician in the field — the requirements in Part IV are for manufacturers.
Article 424 does not cover the wiring for fossil-fuel heating equipment, such as gas, oil, or coal central furnaces. Ins