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Article 430 provides the NEC requirements for installing motors, motor circuits, and related protection devices. You’ll find additional requirements for a special type of motor, the hermetic motor (used in chillers and air conditioners), in Article 440. Other Articles may also apply; see Table 430.5.
A notable characteristic of Article 430 is its sheer size. It’s the biggest article in the NEC. But look a little closer and you'll find something that will help you quickly make sense of it all – Table 430.1.
This table isn’t a design guide; the NEC focuses on hazard prevention [90.1]. But it will help you more efficiently apply the NEC requirements for your motor installation. It outlines the major steps in the logical sequence of completion, and shows you which of the 12 Parts of Article 430 applies to each one.
Another very helpful feature of Article 430 consists of the three Full Load Current (FLC) tables at its very end. These eliminate the need to perform multiple calculations when determining conductor ampacity. We’ll look at FLC more closely in a future issue.
When applying Article 430, keep in mind that it doesn’t work in isolation. As with any other NEC Article, the first four Chapters of the NEC apply except as amended by this Article. In our next issue, we’ll see why we need the amendments made by Article 430 (and why it’s so big).