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NEC Quiz: Article 328 Answers

by Mark Lamendola

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  1. It addresses Medium Voltage Cable (Type MV). [328.1]. It's a single or multi-dielectric insulated cable rated 2001V or higher.
     

  2. You can use Type MV in wet or dry locations. You can use it in raceways. You can use it for direct burial per 300.50. You can use Type MV in messenger-supported wiring conforming to Article 396. So far, it sounds like you can use it just about anywhere, but that's not quite the case.

    When using it in cable trays, you must comply with several requirements in Article 392. If you run it exposed, the installation must conform to 300.37 [328.10]. The NEC does not list all permitted uses. Essentially, you can use it anywhere it's not exposed to direct sunlight (if it's identified for that use, you can) if you have the approval of the Authority Having Jurisdiction.
     

  3. You can't use it where it's exposed to direct sunlight, unless it's identified for the use [328.12].
     

  4. That question does not have a generally applicable answer. The specifics depend upon the exact cable and the application. Type MV cannot be installed by just any electrician. Because of the voltages involved in the (intended) applications, it must be installed by people specifically qualified to install that particular cable [328.14]. This qualification typically comes from the manufacturer.
     

  5. As with the previous question, that question does not have a generally applicable answer. Type MV cable must be terminated by people who are specifically qualified to terminate that cable. They will use very specialized tools, for example electric crimpers with dies made for those specific terminations.

    And before the cable can be put into service, it must be tested by qualified test technicians [328.14]. We strongly advise working with a NETA member firm if you are installing Type MV cable. Shermco, for example, does this kind of work and does it well. Actually, if we may borrow from Carly Simon, nobody does it better.