You can still browse the site but some services may not work properly. This site requires Google Chrome, Firefox, Safari or Internet Explorer 10 and above. For mobile devices use an HTML5 capable browser.Download Chrome
The first four chapters of the NEC apply to all installations (Articles 80 and 90 do, too). Chapter Two contains the requirements for wiring and protection. It begins with Article 200, “Use and Identification of Grounded Conductors.”
To properly apply Article 200, you must know what a “grounded” conductor is and how it differs from a “grounding” conductor.
Article 100 tells us a grounded conductor is a system or circuit conductor that’s intentionally grounded. While a grounding conductor is also intentionally grounded, it’s not a system or circuit conductor. Article 200 doesn’t address grounding conductors. Grounding conductors can be system grounding conductors, in which case they’re connected to earth. They can also be equipment conductors, in which case they don’t actually ground anything; we’ll explain that in a future issue (hint: they bond).
In some wiring systems, the grounded conductor and the neutral conductor are one and the same. But in some systems, the grounded conductor isn’t connected to the neutral (for example, you can wire a corner-grounded delta system without a neutral). So be careful not to use these terms interchangeably.
In 200.2, we find two requirements that are frequently misunderstood and perhaps the winners of the “most violated” award for Article 200:
1. Spec the grounded conductor insulation type the same way you spec that of the ungrounded conductors. Remember, like the ungrounded conductors, it’s a system conductor.
2. The continuity of this conductor can’t depend on a connection to cable armor, raceway, or an enclosure.
Source: Mark Lamendola | Mindconnection