Article 311 Medium Voltage Conductors and Cable.
Code Change Summary: New code article.
In an effort to improve overall usability of the NEC®, the medium voltage requirements located in Article 310 and Article 328 have been combined into new Article 311.
Previously, the ampacity tables for medium voltage cables were located in Article 310 while the installation requirements were located in Article 328. It makes sense to consolidate the requirements into one article.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2017 Code Language:
Article 311 did not exist.
2020 Code Language:
N ARTICLE 311 Medium Voltage Conductors and Cable
Part I. General
311.1 Scope. This article covers the use, installation, construction specifications, and ampacities for Type MV medium voltage conductors and cable.
311.2 Definitions. The definitions in this section shall apply within this article and throughout the Code.
Electrical Ducts. Electrical conduits, or other raceways round in cross section, that are suitable for use underground or embedded in concrete.
Medium Voltage Cable, Type MV. A single or multiconductor solid dielectric insulated cable rated 2001 volts up to and including 35,000 volts, nominal.
Thermal Resistivity. As used in this Code, the heat transfer capability through a substance by conduction.
Informational Note: Thermal resistivity is the reciprocal of thermal conductivity and is designated Rho, which is expressed in the units °C-cm/W.
311.6 Listing Requirements. Type MV cables and associated fittings shall be listed.