Article 340 of the National Electrical Code (NEC) 2023 edition covers requirements for the installation and use of underground conductors and cables in concrete and masonry. This article sets out guidelines for the installation of these conductors and cables in various environments, as well as specific requirements for the type of conductor or cable that can be used for underground applications in concrete and masonry.
NEC 2023 is the latest edition of the National Electrical Code, which is developed and published by the National Fire Protection Association (NFPA). The NEC is a widely used set of standards that is adopted by many jurisdictions in the United States and other countries as the basis for their electrical safety regulations.
Article 340 covers the installation of underground conductors and cables in concrete and masonry, which is a common practice in commercial and industrial electrical installations. These conductors and cables are typically installed in conduits or other types of raceways, and they may be exposed to a variety of environmental hazards, such as moisture, corrosive chemicals, and physical damage.
The first section of Article 340 covers general requirements for underground conductors and cables in concrete and masonry. This section sets out guidelines for the maximum length of these conductors and cables, as well as requirements for the minimum size of the conductor or cable that must be used for different service ratings. The section also includes requirements for the type of insulation that must be used for underground conductors and cables in concrete and masonry, as well as requirements for the type of conduit or raceway that must be used to protect the conductor or cable.
The next section of Article 340 covers requirements for the installation of underground conductors and cables in concrete. This section sets out specific requirements for the type of conduit or raceway that must be used to protect the conductor or cable in concrete, as well as requirements for the depth that the conduit or raceway must be installed. The section also includes requirements for the type of insulation that must be used for underground conductors and cables in concrete.
The following section covers requirements for the installation of underground conductors and cables in masonry. This section applies to conductors and cables that are installed in masonry walls or other types of masonry structures. The section sets out specific requirements for the type of conduit or raceway that must be used to protect the conductor or cable in masonry, as well as requirements for the depth that the conduit or raceway must be installed.
The final section of Article 340 covers specific types of underground conductors and cables, such as Type MI and Type MC cables. These types of conductors and cables have unique installation requirements that must be followed to ensure their safe use. For example, Type MI cables must be installed in a specific type of conduit or raceway, and the maximum allowable length for runs of Type MI cable is limited.
One of the key goals of Article 340 is to ensure that underground conductors and cables in concrete and masonry are installed in a way that minimizes the risk of fire or other hazards. To achieve this goal, the article sets out requirements for the size and type of conductor or cable that must be used for different service ratings. The article also sets out guidelines for the maximum length of underground conductors and cables, as well as the minimum size of the conductor or cable that must be used.
Another key goal of Article 340 is to ensure that underground conductors and cables in concrete and masonry are protected from damage. This is particularly important in environments where the conductor or cable may be exposed to corrosive chemicals or other environmental hazards. The article sets out specific requirements for the type of conduit or raceway that must be used to protect the conductor or cable in concrete and masonry installations.
The requirements for underground conductors and cables in concrete and masonry are also important, as these installations may involve more complex installation procedures than other types of electrical installations. For example, the installation of conduits or raceways in concrete or masonry may require special equipment and expertise to ensure that the installation is done correctly.
The final section of Article 340 covers specific types of underground conductors and cables, such as Type MI and Type MC cables. These types of conductors and cables have unique installation requirements that must be followed to ensure their safe use. For example, Type MI cables must be installed in a specific type of conduit or raceway, and the maximum allowable length for runs of Type MI cable is limited.
It’s important to note that Article 340 is just one part of the NEC, and there are many other articles that cover different aspects of electrical safety. However, Article 340 is an important part of the NEC as it provides specific guidelines for the installation and use of underground conductors and cables in concrete and masonry.
In conclusion, Article 340 of NEC 2023 covers requirements for the installation and use of underground conductors and cables in concrete and masonry. The article sets out guidelines for the installation of these conductors and cables in various environments, as well as specific requirements for the type of conductor or cable that can be used for underground applications in concrete and masonry. The goal of Article 340 is to ensure that underground conductors and cables in concrete and masonry are installed in a way that minimizes the risk of fire or other hazards, and that they are protected from damage. Following the guidelines set out in Article 340 can help ensure that electrical installations are safe and reliable.