“Other Articles” of NFPA 70 That Apply to Fire Alarm Systems
Article 760 (Fire Alarm Systems) of NFPA 70 (National Electrical Code) governs fire alarm system wiring and equipment, including all circuits controlled and powered by the fire alarm. Article 760.3 (Other Articles) identifies other sections of NFPA 70 that also apply to fire alarm systems. In this post, we will look at some of these requirements.
760.3 states that only sections of Article 300 (General Requirements for Wiring Methods and Materials) that are specifically referenced in Article 760.3 apply to fire alarm systems. Chapter 3 generally applies to all electrical wiring, but NFPA 70 states in this article that only specific parts apply to fire alarm requirements.
Article 300.21 covers spread of fire or products of combustion. This requires that wiring in spaces be installed so that it does not substantially increase the possibility of the spread of fire. This includes sealing penetrations through fire resistant surfaces to maintain the fire resistance rating (fire stopping).
Article 300.22 restricts cable using in environmental air spaces (plenums) be in metal conduit or raceway, or be a plenum rated cable.
Equipment installed in hazardous (classified) locations shall be installed based on the requirements of the Article governing the application (Articles 500-517). Hazardous locations are areas where fire or explosion hazards exist due to gasses or material in the atmosphere. Equipment is required to be listed for the application and installed based on the requirements of the classification.
Corrosive, damp, and wet locations have special requirements for cabling and raceways covered in 110.11, 300.5(B), 300.6, 300.9, and 310.10(G). This includes locations above and below ground, exposed to sunlight, and in concrete.
Article 725 covers building control circuits like fan or elevator control. The parts of the circuits powered by the fire alarm are covered by Article 760, while the parts not powered by the fire alarm are covered by Article 725. For example, a failsafe relay powered by the fire alarm panel is Article 760 up to the relay, but the contacts of the relay controlling the device or circuit are covered by Article 725.
Article 770 cover fiber optic cable. The class of circuit for the cabling is covered by NFPA 72, Chapter 12 (Circuits and Pathways), but the application and installation of the cable itself are governed by Article 770.
Article 300.8 specifically prohibits running electrical cable and raceway in the same pipe or tube as nonelectric systems like steam, water, or gas. Specific sections of Article 760 details the requirements for mixing fire alarm circuits with other electrical circuits depending on the classification of the circuit as power-limited or nonpower-limited.
Article 300.7(A) covers raceways or sleeves exposed to different temperatures, like running in or out of a building or refrigerated space. The sleeves are required to include material to help prevent condensation.
Vertical installation of circuit integrity (CI) cable shall be installed in accordance with 300.19. Table 300.19(A) give the support intervals based on the gauge of the cable.
Article 300.17 states that the size and number of conductors in a raceway shall not be more than would allow dissipation of heat and withdraw of the conductors from the raceway without damaging their insulation.
Article 300.15(C ) requires bushings where cables emerge from the raceway to protect the cable from damage.
Article 300.4(D) requires that cable and raceways parallel to framing members be installed so that surface of the cable is not less than 1-1/4 inch from the nearest edge of the framing member where the nail or screw is likely to penetrate. Additionally, where the distance cannot be maintained, it shall be protected by steel plate or sleeve at least 1/16 inch thick.
While it is common for many code officials to require compliance with other parts of NFPA 70, particularly the general requirements of Article 300, the code itself does not specifically require it.