The National Electrical Code (NEC) includes Article 320, which pertains to the installation and use of armored cable.
Armored cable, also known as armored wire, is a type of electrical cable that is used to provide mechanical protection and to prevent damage to the conductors inside. Armored cable consists of one or more conductors that are insulated with a layer of material such as plastic or rubber, and then covered with a metal armor. The armor may be made of steel or aluminum, and is designed to protect the conductors from damage due to impact, vibration, or other hazards.
Article 320 of the NEC sets forth the requirements for the design, installation, and use of armored cable. These requirements are intended to ensure the safety and reliability of electrical systems that use armored cable.
Section 320.10 of the NEC establishes the general requirements for the use of armored cable. Armored cable must be used in locations where the cable is exposed to physical damage or where it must be installed in hazardous locations. Hazardous locations include areas where there is a risk of fire or explosion, such as chemical plants or oil refineries. Armored cable may also be used in locations where it is necessary to protect the conductors from mechanical damage, such as in industrial settings or in outdoor environments.
Section 320.12 of the NEC outlines the requirements for the construction of armored cable. Armored cable must be constructed with a grounding conductor that is insulated from the armor. The armor must be designed to withstand the mechanical stresses that may be imposed on it during installation and use, and it must provide adequate protection to the conductors inside. The NEC also provides guidance on the minimum thickness of the armor required based on the type of cable and the application.
Section 320.16 of the NEC establishes the requirements for the installation of armored cable. Armored cable must be installed so that the armor is in contact with a metal enclosure or grounded conductor. This ensures that any electrical faults or short circuits are safely grounded, rather than creating a dangerous electrical shock hazard. The NEC also provides guidance on the minimum bend radius and the maximum pull tension that may be applied to the cable during installation.
Section 320.18 of the NEC outlines the requirements for the protection of armored cable from damage. Armored cable must be protected from damage due to nails, screws, or other fasteners that may be driven into the walls, ceilings, or floors. The NEC provides guidance on the types of protection required based on the location of the cable and the potential for damage.
Section 320.20 of the NEC establishes the requirements for the use of fittings with armored cable. Fittings must be designed and installed so that they provide adequate mechanical protection to the cable and do not damage the insulation or the armor. The NEC also provides guidance on the types of fittings that may be used with armored cable and the minimum spacing requirements between fittings.
Section 320.22 of the NEC outlines the requirements for the grounding of armored cable. Armored cable must be grounded to the equipment grounding conductor or to the grounding electrode system of the building. The NEC provides guidance on the methods that may be used to ground armored cable, such as the use of grounding screws, clips, or pigtails.
In conclusion, Article 320 of the NEC sets forth the requirements for the design, installation, and use of armored cable. Armored cable is an essential component of many electrical systems, and its proper installation and use are critical to the safety and reliability of the system. By following the requirements set forth in Article 320, electricians and contractors can ensure that armored cable is installed safely and in compliance with national safety standards.
One of the key requirements of Article 320 is the general requirement for the use of armored cable in locations where the cable is exposed to physical damage or where it must be installed in hazardous locations. This ensures that the conductors inside the cable are protected from potential hazards such as impact, vibration, or exposure to chemicals.
Another important requirement of Article 320 is the construction of the armored cable itself. The cable must be constructed with a grounding conductor that is insulated from the armor, and the armor must be designed to provide adequate protection to the conductors inside. The minimum thickness of the armor required is specified by the NEC based on the type of cable and the application.
Additionally, Article 320 requires that armored cable be installed so that the armor is in contact with a metal enclosure or grounded conductor. This ensures that any electrical faults or short circuits are safely grounded, rather than creating a dangerous electrical shock hazard. The NEC also provides guidance on the minimum bend radius and the maximum pull tension that may be applied to the cable during installation.
It is also important to note that Article 320 provides guidance on the protection of armored cable from damage due to nails, screws, or other fasteners that may be driven into the walls, ceilings, or floors. This is especially important for cables installed in areas where they may be subject to impact or where there is a risk of damage due to construction work or other activities.
Furthermore, Article 320 specifies the types of fittings that may be used with armored cable and the minimum spacing requirements between fittings. Fittings must be designed and installed so that they provide adequate mechanical protection to the cable and do not damage the insulation or the armor.
Finally, Article 320 requires that armored cable be grounded to the equipment grounding conductor or to the grounding electrode system of the building. The NEC provides guidance on the methods that may be used to ground armored cable, such as the use of grounding screws, clips, or pigtails.
In summary, Article 320 of the NEC is an essential safety standard that sets forth the requirements for the installation and use of armored cable. Compliance with these regulations is critical for ensuring the safety and reliability of electrical systems in homes, buildings, and other structures. Electricians and contractors must be familiar with the requirements of Article 320 and take care to ensure that all armored cable is installed and used in compliance with these regulations. By doing so, they can help prevent electrical fires, electrocution, and other safety hazards, and ensure that electrical systems are safe and reliable for years to come.