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ARTICLE 770

Optical Fiber Cables

  1. Insulated Continuous Line-Type Fire Detectors. Insulated continuous line-type fire detectors shall be rated in accordance with 760.179(C), listed as being resistant to the spread of fire in accordance with 760.179(D) through (F), and marked in accordance with 760.179(I), and the jacket compound shall have a high degree of abrasion resistance.

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Informational Note: See Informational Note Figure 800(a) and Informational Note Figure 800(b) for illustrative application of a bonding conductor or grounding electrode conductor.

Part I. General

  1. Scope. This article covers the installation of optical fiber cables. This article does not cover the construction of optical fiber cables.
  2. Definitions. See Part I of Article 100. For purposes of this article, the following additional definitions apply.Abandoned Optical Fiber Cable. Installed optical fiber cable that is not terminated at equipment other than a connector and not identified for future use with a tag.•Cable Sheath. A covering over the optical fiber assembly thatincludes one or more jackets and may include one or more metallic members or strength members.•
    Informational Note: See Part I of Article 100 for two other defi‐nitions of Exposed: Exposed (as applied to live parts) and Exposed (as applied to wiring methods).Exposed (to Accidental Contact). A conductive optical fiber cable in such a position that, in case of failure of supports or insulation, contact between the cable’s non–current-carrying conductive members and an electrical circuit might result.
    •Point of Entrance. The point within a building at which theoptical fiber cable emerges from an external wall or from a concrete floor slab.
  3. Other Articles. Installations of optical fiber cables shall comply with 770.3(A) and (B). Only those sections of Chap‐ ter 2 and Article 300 referenced in this article shall apply to optical fiber cables.
  1. Hazardous (Classified) Locations. Listed optical fiber cables shall be permitted to be installed in hazardous (classi‐ fied) locations. The cables shall be sealed in accordance with the requirements of 501.15, 502.15, 505.16, or 506.16, as appli‐ cable.
  2. Cables in Ducts for Dust, Loose Stock, or Vapor Removal. The requirements of 300.22(A) for wiring systems shall apply to conductive optical fiber cables.
  3. Composite Cables. Composite optical fiber cables shall be classified as electrical cables in accordance with the type of electrical conductors. They shall be constructed, listed, and marked in accordance with the appropriate article for each type of electrical cable.

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770.21 Access to Electrical Equipment Behind Panels Designed

to Allow Access. Access to electrical equipment shall not be denied by an accumulation of optical fiber cables that prevents removal of panels, including suspended ceiling panels.

  1. Mechanical Execution of Work. Optical fiber cables shall be installed in a neat and workmanlike manner. Cables installed exposed on the surface of ceilings and sidewalls shall be supported by the building structure in such a manner that the cable will not be damaged by normal building use. Such cables shall be secured by hardware including straps, staples, cable ties, hangers, or similar fittings designed and installed so as not to damage the cable. The installation shall also conform with 300.4(D) through (G) and 300.11. Nonmetallic cable ties and other nonmetallic cable accessories used to secure and support cables in other spaces used for environmental air (plenums) shall be listed as having low smoke and heat release properties.Informational Note No. 1: Accepted industry practices are described in ANSI/NECA/BICSI 568-2006, Standard for Installing Commercial Building Telecommunications Cabling; ANSI/ NECA/FOA 301-2009, Standard for Installing and Testing Fiber Optic Cables; and other ANSI-approved installation standards.Informational Note No. 2: See 4.3.11.2.6.5 and 4.3.11.5.5.6 of NFPA 90A-2012, Standard for the Installation of Air-Conditioning and Ventilating Systems, for discrete combustible components installed in accordance with 300.22(C).
    Informational Note No. 3: Paint, plaster, cleaners, abrasives,corrosive residues, or other contaminants may result in an unde‐ termined alteration of optical fiber cable properties.
  2. Abandoned Cables. The accessible portion of aban‐ doned optical fiber cables shall be removed. Where cables areidentified for future use with a tag, the tag shall be of sufficient durability to withstand the environment involved.
  3. Spread of Fire or Products of Combustion. Installa‐ tions of optical fiber cables and communications raceways in hollow spaces, vertical shafts, and ventilation or air-handling ducts shall be made so that the possible spread of fire or prod‐ ucts of combustion will not be substantially increased. Open‐ ings around penetrations of optical fiber cables and communications raceways through fire-resistant–rated walls, partitions, floors, or ceilings shall be firestopped using approved methods to maintain the fire resistance rating.

Informational Note: Directories of electrical construction mate‐ rials published by qualified testing laboratories contain many listing installation restrictions necessary to maintain the fire- resistive rating of assemblies where penetrations or openings are made. Building codes also contain restrictions on membrane penetrations on opposite sides of a fire resistance–rated wall assembly. An example is the 600-mm (24-in.) minimum horizon‐ tal separation that usually applies between boxes installed on opposite sides of the wall. Assistance in complying with 770.26 can be found in building codes, fire resistance directories, and product listings.

Part II. Cables Outside and Entering Buildings

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770.44 Overhead (Aerial) Optical Fiber Cables. Overhead optical fiber cables containing a non–current-carrying metallic member entering buildings shall comply with 840.44(A) and (B).

  1. On Poles and In-Span. Where outside plant optical fiber cables and electric light or power conductors are supported by the same pole or are run parallel to each other in-span, the conditions described in 770.44(A)(1) through (A)(4) shall be met.
    1. Relative Location. Where practicable, the outside plant optical fiber cables shall be located below the electric light or power conductors.
    2. Attachment to Cross-Arms. Attachment of outside plant optical fiber cables to a cross-arm that carries electric light or power conductors shall not be permitted.
    3. Climbing Space. The climbing space through outside plant optical fiber cables shall comply with the requirements of 225.14(D).
    4. Clearance. Supply service drops and sets of overhead serv‐ ice conductors of 0 to 750 volts running above and parallel to optical fiber cable service drops shall have a minimum separa‐ tion of 300 mm (12 in.) at any point in the span, including the point of their attachment to the building. Clearance of not less than 1.0 m (40 in.) shall be maintained between the two serv‐ ices at the pole.
  2. Above Roofs. Outside plant optical fiber cables shall have a vertical clearance of not less than 2.5 m (8 ft) from all points of roofs above which they pass.

Exception No. 1: The requirement of 770.44(B) shall not apply to auxiliary buildings such as garages and the like.

Exception No. 2: A reduction in clearance above only the overhanging portion of the roof to not less than 450 mm (18 in.) shall be permitted if

(a) not more than 1.2 m (4 ft) of optical fiber cable service drop cable

passes above the roof overhang, and (b) the cable is terminated at a through- or above-the-roof raceway or approved support.

Exception No. 3: Where the roof has a slope of not less than 100 mm in 300 mm (4 in. in 12 in.), a reduction in clearance to not less than 900 mm (3 ft) shall be permitted.

Informational Note: For additional information regarding over‐ head wires and cables, see ANSI/IEEE C2-2012, National Electric Safety Code, Part 2, Safety Rules for Overhead Lines.

  1. Underground Optical Fiber Cables Entering Buildings. Underground optical fiber cables entering buildings shall comply with 770.47(A) and (B).
    1. Underground Systems with Electric Light, Power, Class 1, or Non–Power-Limited Fire Alarm Circuit Conductors. Underground conductive optical fiber cables entering build‐ ings with electric light, power, Class 1, or non–power-limited fire alarm circuit conductors in a raceway, handhole enclosure, or manhole shall be located in a section separated from such conductors by means of brick, concrete, or tile partitions or by means of a suitable barrier.
    2. Direct-Buried Cables and Raceways. Direct-buried conductive optical fiber cables shall be separated by at least 300 mm (12 in.) from conductors of any electric light, power, non–power-limited fire alarm circuit conductors, or Class 1 circuit.
    Exception No. 1: Direct-buried conductive optical fiber cables shall not be required to be separated by at least 300 mm (12 in.) from electric service conductors where electric service conductors are installed in race‐ ways or have metal cable armor.Exception No. 2: Direct-buried conductive optical fiber cables shall not be required to be separated by at least 300 mm (12 in.) from electric light or power branch-circuit or feeder conductors, non–power-limited fire alarm circuit conductors, or Class 1 circuit conductors where electric light or power branch-circuit or feeder conductors, non–power-limited fire alarm circuit conductors, or Class 1 circuit conductors are installed in a raceway or in metal-sheathed, metal-clad, or Type UF or Type USE cables.
  2. Unlisted Cables Entering Buildings.
    1. Conductive and Nonconductive Cables. Unlisted conduc‐ tive and nonconductive outside plant optical fiber cables shall be permitted to be installed in building spaces, other than risers, ducts used for environmental air, plenums used for envi‐ ronmental air, and other spaces used for environmental air, where the length of the cable within the building, measured from its point of entrance, does not exceed 15 m (50 ft) and the cable enters the building from the outside and is termina‐ ted in an enclosure.The point of entrance shall be permitted to be extended from the penetration of the external wall or floor slab by continuously enclosing the entrance optical fiber cables in rigid metal conduit (RMC) or intermediate metal conduit (IMC) to the point of emergence.Informational Note: Splice cases or terminal boxes, both metal‐ lic and plastic types, typically are used as enclosures for splicing or terminating optical fiber cables.•
    2. Nonconductive Cables in Raceway. Unlisted nonconduc‐
    tive outside plant optical fiber cables shall be permitted to enter the building from the outside and shall be permitted to be installed in any of the following raceways:
    1. Intermediate metal conduit (IMC)
    2. Rigid metal conduit (RMC)
    3. Rigid polyvinyl chloride conduit (PVC)
    4. Electrical metallic tubing (EMT)
    imagemental air, and other spaces used for environmental air.Unlisted nonconductive outside plant cables installed in rigid polyvinyl chloride conduit (PVC) or electrical metallic tubing (EMT) shall not be permitted to be installed in risers, ducts used for environmental air, plenums used for environ‐Metallic
  3. Metallic Entrance Conduit Grounding.

conduit containing optical fiber entrance cable shall be connected by a bonding conductor or grounding electrode conductor to a grounding electrode in accordance with 770.100(B).

Part III. Protection

770.93 Grounding or Interruption of Non–Current-Carrying Metallic Members of Optical Fiber Cables. Optical fiber cables entering the building or terminating on the outside of the building shall comply with 770.93(A) or (B).

  1. Entering Buildings. In installations where an optical fiber cable is exposed to contact with electric light or power conduc‐ tors and the cable enters the building, the non–current- carrying metallic members shall be either grounded as specified in 770.100, or interrupted by an insulating joint or equivalent device. The grounding or interruption shall be as close as practicable to the point of entrance.•
  2. Terminating on the Outside of Buildings. In installations

where an optical fiber cable is exposed to contact with electric light or power conductors and the cable is terminated on the outside of the building, the non–current-carrying metallic members shall be either grounded as specified in 770.100, or interrupted by an insulating joint or equivalent device. The grounding or interruption shall be as close as practicable to the point of termination of the cable.

Part IV. Grounding Methods

770.100 Entrance Cable Bonding and Grounding. Where required, the non–current-carrying metallic members of opti‐ cal fiber cables entering buildings shall be bonded or groun‐ ded as specified in 770.100(A) through (D).

  1. Bonding Conductor or Grounding Electrode Conductor.
    1. Insulation. The bonding conductor or grounding elec‐ trode conductor shall be listed and shall be permitted to be insulated, covered, or bare.
    2. Material. The bonding conductor or grounding electrode conductor shall be copper or other corrosion-resistant conduc‐ tive material, stranded or solid.
    3. Size. The bonding conductor or grounding electrode conductor shall not be smaller than 14 AWG. It shall have a current-carrying capacity not less than that of the grounded metallic member(s). The bonding conductor or grounding electrode conductor shall not be required to exceed 6 AWG.
    4. Length. The bonding conductor or grounding electrode conductor shall be as short as practicable. In one- and two- family dwellings, the bonding conductor or grounding
      electrode conductor shall be as short as practicable not to exceed 6.0 m (20 ft) in length.Informational Note: Similar bonding conductor or grounding electrode conductor length limitations applied at apartment buildings and commercial buildings help to reduce voltages that may develop between the building’s power and communications systems during lightning events.Exception: In one- and two-family dwellings where it is not practicable to achieve an overall maximum bonding conductor or grounding elec‐ trode conductor length of 6.0 m (20 ft), a separate ground rod meeting the minimum dimensional criteria of 770.100(B)(3)(2) shall be driven, the grounding electrode conductor shall be connected to the sepa‐ rate ground rod in accordance with 770.100(C), and the separate ground rod shall be bonded to the power grounding electrode system in accordance with 770.100(D).
    5. Run in Straight Line. The bonding conductor or ground‐ ing electrode conductor shall be run in as straight a line as practicable.
    6. Physical Protection. Bonding conductors and grounding electrode conductors shall be protected where exposed to phys‐ ical damage. Where the bonding conductor or grounding elec‐ trode conductor is installed in a metal raceway, both ends of the raceway shall be bonded to the contained conductor or to the same terminal or electrode to which the bonding conduc‐ tor or grounding electrode conductor is connected.
  2. Electrode. The bonding conductor and grounding elec‐ trode conductor shall be connected in accordance with 770.100(B)(1), (B)(2), or (B)(3).
    1. In Buildings or Structures with an Intersystem Bonding Termination. If the building or structure served has an inter‐ system bonding termination as required by 250.94, the bonding conductor shall be connected to the intersystem bonding termination.•
    2. In Buildings or Structures with Grounding Means. If anintersystem bonding termination is established, 250.94(A) shall apply.If the building or structure served has no intersystem bond‐ ing termination, the bonding conductor or grounding elec‐ trode conductor shall be connected to the nearest accessible location on one of the following:
      1. The building or structure grounding electrode system as covered in 250.50
      2. The grounded interior metal water piping system, within1.5 m (5 ft) from its point of entrance to the building, as covered in 250.52
      3. The power service accessible means external to enclo‐ sures using the options identified in 250.94(A), Excep‐ tion
      4. The nonflexible metallic power service raceway
      5. The service equipment enclosure
      6. The grounding electrode conductor or the grounding electrode conductor metal enclosure of the power service
      7. The grounding electrode conductor or the grounding electrode of a building or structure disconnecting means that is grounded to an electrode as covered in 250.32
      (3) In Buildings or Structures Without Intersystem Bonding Termination or Grounding Means. If the building or structure served has no intersystem bonding termination or groundingmeans, as described in 770.100(B)(2), the grounding electrode conductor shall be connected to either of the following:
      1. To any one of the individual grounding electrodes descri‐ bed in 250.52(A)(1), (A)(2), (A)(3), or (A)(4).
      2. If the building or structure served has no grounding means, as described in 770.100(B)(2) or (B)(3)(1), to any one of the individual grounding electrodes described in 250.52(A)(7) and (A)(8) or to a ground rod or pipe not less than 1.5 m (5 ft) in length and 12.7 mm (1∕2 in.) in diameter, driven, where practicable, into permanently damp earth and separated from lightning protection system conductors as covered in 800.53 and at least 1.8 m (6 ft) from electrodes of other systems. Steam, hot water pipes, or lightning protection system conductors shall not be employed as electrodes for non–current-carrying metallic members.
  3. Electrode Connection. Connections to grounding electro‐ des shall comply with 250.70.
  4. Bonding of Electrodes. A bonding jumper not smaller than 6 AWG copper or equivalent shall be connected between the grounding electrode and power grounding electrode system at the building or structure served where separate elec‐ trodes are used.

Exception: At mobile homes as covered in 770.106.

Informational Note No. 1: See 250.60 for connection to a light‐ ning protection system.

Informational Note No. 2: Bonding together of all separate elec‐ trodes limits potential differences between them and between their associated wiring systems.

770.106 Grounding and Bonding of Entrance Cables at Mobile Homes.

  1. Grounding. Grounding shall comply with 770.106(A)(1) and (A)(2).
    1. Where there is no mobile home service equipment loca‐ ted within 9.0 m (30 ft) of the exterior wall of the mobile home it serves, the non–current-carrying metallic members of optical fiber cables entering the mobile home shall be grounded in accordance with 770.100(B)(3).
    2. Where there is no mobile home disconnecting means grounded in accordance with 250.32 and located within
    9.0 m (30 ft) of the exterior wall of the mobile home it serves, the non–current-carrying metallic members of optical fiber cables entering the mobile home shall be grounded in accordance with 770.100(B)(3).
  2. Bonding. The grounding electrode shall be bonded to the metal frame or available grounding terminal of the mobile home with a copper conductor not smaller than 12 AWG under either of the following conditions:
  1. Where there is no mobile home service equipment or disconnecting means as in 770.106(A)
  2. Where the mobile home is supplied by cord and plug

Part V. Installation Methods Within Buildings

770.110 Raceways and Cable Routing Assemblies for Optical Fiber Cables.

  1. Types of Raceways. Optical fiber cables shall be permit‐ ted to be installed in any raceway that complies with either 770.110(A)(1) or (A)(2) and in cable routing assemblies instal‐ led in compliance with 770.110(C).
    1. Raceways Recognized in Chapter 3. Optical fiber cables shall be permitted to be installed in any raceway included in Chapter 3. The raceways shall be installed in accordance with the requirements of Chapter 3.
    2. Communications Raceways. Optical fiber cables shall be permitted to be installed in plenum communications raceways, riser communications raceways, and general-purpose commu‐ nications raceways selected in accordance with Table 800.154(b), listed in accordance with 800.113, and installed in accordance with 362.24 through 362.56, where the require‐ ments applicable to electrical nonmetallic tubing (ENT) apply.
    3. Innerduct for Optical Fiber Cables. Listed plenum communications raceway, listed riser communications raceway, and listed general-purpose communications raceway selected in accordance with the provisions of Table 800.154(b) shall be permitted to be installed as innerduct in any type of listed race‐ way permitted in Chapter 3.
  2. Raceway Fill for Optical Fiber Cables. Raceway fill for optical fiber cables shall comply with either 770.110(B)(1) or (B)(2).
    1. Without Electric Light or Power Conductors. Where opti‐ cal fiber cables are installed in raceway without electric light or power conductors, the raceway fill requirements of Chapters 3 and 9 shall not apply.
    2. Nonconductive Optical Fiber Cables with Electric Light or Power Conductors. Where nonconductive optical fiber cables are installed with electric light or power conductors in a race‐ way, the raceway fill requirements of Chapters 3 and 9 shall apply.
  3. Cable Routing Assemblies. Optical fiber cables shall be permitted to be installed in plenum cable routing assemblies, riser cable routing assemblies, and general-purpose cable rout‐ ing assemblies selected in accordance with Table 800.154(c), listed in accordance with 800.182, and installed in accordance with 800.110(C) and 800.113.

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  1. Installation of Optical Fiber Cables. Installation ofoptical fiber cables shall comply with 770.113(A) through (J). Installation of raceways and cable routing assemblies shall comply with 770.110.
    1. Listing. Optical fiber cables installed in buildings shall be listed in accordance with 770.179.Exception: Optical fiber cables that are installed in compliance with770.48 shall not be required to be listed.
    2. Ducts Specifically Fabricated for Environmental Air. The following cables shall be permitted in ducts specifically fabrica‐ ted for environmental air as described in 300.22(B) if they are directly associated with the air distribution system:
      1. Up to 1.22 m (4 ft) of Types OFNP and OFCP
      2. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in raceways that are installed in compliance with 300.22(B)
      Informational Note: For information on fire protection of wiring installed in fabricated ducts, see 4.3.4.1 and 4.3.11.3.3 of NFPA 90A -2015, Standard for the Installation of Air-Conditioning and Ventilating Systems.
    3. Other Spaces Used for Environmental Air (Plenums). The following cables shall be permitted in other spaces used for environmental air as described in 300.22(C):
      1. Types OFNP and OFCP
      2. Types OFNP and OFCP installed in plenum communica‐ tions raceways listed in accordance with 800.182
      3. Types OFNP and OFCP installed in plenum cable routing assemblies listed in accordance with 800.182
      4. Types OFNP and OFCP supported by open metallic cable trays or cable tray systems
      5. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in raceways that are installed in compliance with 300.22(C)
      6. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC supported by solid bottom metal cable trays with solid metal covers in other spaces used for environ‐ mental air (plenums), as described in 300.22(C)
      7. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in plenum communications raceways, riser communications raceways, or general-purpose communications raceways listed in accordance with 800.182 or supported by solid bottom metal cable trays with solid metal covers in other spaces used for environ‐ mental air (plenums), as described in 300.22(C)
      Informational Note: For information on fire protection of wiring installed in other spaces used for environmental air, see 4.3.11.2, 4.3.11.4, and 4.3.11.5 of NFPA 90A-2015, Standard for the Installation of Air-Conditioning and Ventilating Systems.•
    4. Risers — Cables in Vertical Runs. The following cablesshall be permitted in vertical runs penetrating one or more floors and in vertical runs in a shaft:
      1. Types OFNP, OFCP, OFNR, and OFCR
      2. Types OFNP, OFCP, OFNR, and OFCR installed in:
        1. Plenum communications raceways
        2. Plenum cable routing assemblies
        3. Riser communications raceways
        4. Riser cable routing assembliesInformational Note: See 770.26 for firestop requirements for floor penetrations.
    5. Risers — Cables and Innerducts in Metal Raceways. The following cables and innerducts shall be permitted in metal raceways in a riser having firestops at each floor:
      1. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC
      2. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in:
        1. Plenum communications raceways (innerduct)
        2. Riser communications raceways (innerduct)
        3. General-purpose communications raceways (inner‐ duct)
      Informational Note: See 770.26 for firestop requirements for floor penetrations.
    6. Risers — Cables in Fireproof Shafts. The following cables shall be permitted to be installed in fireproof riser shafts having firestops at each floor:
      1. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC
      2. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in:
        1. Plenum communications raceways
        2. Plenum cable routing assemblies
        3. Riser communications raceways
        4. Riser cable routing assemblies
        5. General-purpose communications raceways
        6. General-purpose cable routing assemblies
      Informational Note: See 770.26 for firestop requirements for floor penetrations.
    7. Risers — One- and Two-Family Dwellings. The following cables shall be permitted in one- and two-family dwellings:
      1. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC
      2. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in:
        1. Plenum communications raceways
        2. Plenum cable routing assemblies
        3. Riser communications raceways
        4. Riser cable routing assemblies
        5. General-purpose communications raceways
        6. General-purpose cable routing assemblies
    8. Cable Trays. The following cables shall be permitted to be supported by cable trays:
    1. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC
    2. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in:
      1. Plenum communications raceways
      2. Riser communications raceways
      3. General-purpose communications raceways
    1. Distributing Frames and Cross-Connect Arrays. The following cables shall be permitted to be installed in distribut‐ ing frames and cross-connect arrays:
      1. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC
      2. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in:
        1. Plenum communications raceways
        2. Plenum cable routing assemblies
        3. Riser communications raceways
        4. Riser cable routing assemblies
        5. General-purpose communications raceways
        6. General-purpose cable routing assemblies
    2. Other Building Locations. The following cables shall be permitted to be installed in building locations other than the locations covered in 770.113(B) through (I):
    1. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC
    2. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in:
      1. Plenum communications raceways
      2. Plenum cable routing assemblies
      3. Riser communications raceways
      4. Riser cable routing assemblies
      5. General-purpose communications raceways
      6. General-purpose cable routing assemblies
    3. Types OFNP, OFCP, OFNR, OFCR, OFNG, OFCG, OFN, and OFC installed in a raceway of a type recognized in Chapter 3
  2. Grounding. Non–current-carrying conductive members of optical fiber cables shall be bonded to a grounded equipment rack or enclosure, or grounded in accordance with the grounding methods specified by 770.110(B)(2).

770.133 Installation of Optical Fibers and Electrical Conduc‐ tors.

  1. With Conductors for Electric Light, Power, Class 1, Non– Power-Limited Fire Alarm, or Medium Power Network- Powered Broadband Communications Circuits. When optical fibers are within the same composite cable for electric light, power, Class 1, non–power-limited fire alarm, or medium-power network-powered broadband communications circuits operat‐ ing at 1000 volts or less, they shall be permitted to be installed only where the functions of the optical fibers and the electrical conductors are associated.Nonconductive optical fiber cables shall be permitted to occupy the same cable tray or raceway with conductors for elec‐ tric light, power, Class 1, non–power-limited fire alarm, Type ITC, or medium-power network-powered broadband communications circuits operating at 1000 volts or less. Conductive optical fiber cables shall not be permitted to occupy the same cable tray or raceway with conductors for elec‐ tric light, power, Class 1, non–power-limited fire alarm, Type ITC, or medium-power network-powered broadband communi‐ cations circuits.Optical fibers in composite optical fiber cables containing only current-carrying conductors for electric light, power, or Class 1 circuits rated 1000 volts or less shall be permitted to occupy the same cabinet, cable tray, outlet box, panel, raceway, or other termination enclosure with conductors for electric light, power, or Class 1 circuits operating at 1000 volts or less.Nonconductive optical fiber cables shall not be permitted to occupy the same cabinet, outlet box, panel, or similar enclo‐ sure housing the electrical terminations of an electric light, power, Class 1, non–power-limited fire alarm, or medium-power network-powered broadband communications circuit.Exception No. 1: Occupancy of the same cabinet, outlet box, panel, or similar enclosure shall be permitted where nonconductive optical fiber cable is functionally associated with the electric light, power, Class 1, non–power-limited fire alarm, or medium-power network-powered broad‐ band communications circuit.Exception No. 2: Occupancy of the same cabinet, outlet box, panel, or similar enclosure shall be permitted where nonconductive optical fiber cables are installed in factory- or field-assembled control centers.Exception No. 3: In industrial establishments only, where conditions of maintenance and supervision ensure that only qualified persons service the installation, nonconductive optical fiber cables shall be permitted with circuits exceeding 1000 volts.Exception No. 4: In industrial establishments only, where conditions of maintenance and supervision ensure that only qualified persons service the installation, optical fibers in composite optical fiber cables contain‐
    ing current-carrying conductors operating over 1000 volts shall be permitted to be installed.Exception No. 5: Where all of the conductors of electric light, power, Class 1, nonpower-limited fire alarm, and medium-power network- powered broadband communications circuits are separated from all of the optical fiber cables by a permanent barrier or listed divider.•
  2. With Other Circuits. Optical fibers shall be permitted inthe same cable, and conductive and nonconductive optical fiber cables shall be permitted in the same raceway, cable tray, box, enclosure, or cable routing assembly, with conductors of any of the following:
    1. Class 2 and Class 3 remote-control, signaling, and power- limited circuits in compliance with Article 645 or Parts I and III of Article 725
    2. Power-limited fire alarm systems in compliance with Parts I and III of Article 760
    1. Communications circuits in compliance with Parts I andV of Article 800
    2. Community antenna television and radio distribution systems in compliance with Parts I and V of Article 820
    3. Low-power network-powered broadband communications circuits in compliance with Parts I and V of Article 830
  3. Support of Optical Fiber Cables. Raceways shall be used for their intended purpose. Optical fiber cables shall not be strapped, taped, or attached by any means to the exterior of any conduit or raceway as a means of support.

Exception: Overhead (aerial) spans of optical fiber cables shall be permitted to be attached to the exterior of a raceway-type mast intended for the attachment and support of such cables.

770.154 Applications of Listed Optical Fiber Cables. Permit‐ ted and nonpermitted applications of listed optical fiber cables shall be as indicated in Table 770.154(a). The permitted appli‐ cations shall be subject to the installation requirements of

770.110 and 770.113. The substitutions for optical fiber cables in Table 770.154(b) and illustrated in Figure 770.154 shall be permitted.

Part VI. Listing Requirements

  1. Optical Fiber Cables. Optical fiber cables shall be listed and identified in accordance with 770.179(A) through(F) and shall be marked in accordance with Table 770.179. Optical fiber cables shall have a temperature rating of not less than 60°C (140°F). Temperature rating shall be marked on the jacket of optical fiber cables that have a temperature rating exceeding 60°C (140°F).
    1. Types OFNP and OFCP. Types OFNP and OFCP noncon‐ ductive and conductive optical fiber plenum cables shall be suitable for use in ducts, plenums, and other space used for environmental air and shall also have adequate fire-resistant and low smoke producing characteristics.Informational Note: One method of defining a cable that has adequate fire-resistant and low-smoke producing characteristics is that the cable exhibits a maximum peak optical density of 0.50 or less, an average optical density of 0.15 or less, and a maxi‐ mum flame spread distance of 1.52 m (5 ft) or less when tested in accordance with NFPA 262 -2015, Standard Method of Test for Flame Travel and Smoke of Wires and Cables for Use in Air-Handling Spaces.
    2. Types OFNR and OFCR. Types OFNR and OFCR nonconductive and conductive optical fiber riser cables shall be suitable for use in a vertical run in a shaft or from floor to floor and shall also have the fire-resistant characteristics capa‐ ble of preventing the carrying of fire from floor to floor.Informational Note: One method of defining fire-resistant char‐ acteristics capable of preventing the carrying of fire from floor to floor is that the cables pass the requirements of ANSI/ UL 1666-2011, Standard Test for Flame Propagation Height of Electri‐ cal and Optical-Fiber Cable Installed Vertically in Shafts.
    3. Types OFNG and OFCG. Types OFNG and OFCG nonconductive and conductive general-purpose optical fiber cables shall be suitable for general-purpose use, with the excep‐ tion of risers and plenums, and shall also be resistant to the spread of fire.Informational Note: One method of defining resistant to the spread of fire is for the damage (char length) not to exceed 1.5 m (4 ft 11 in.) when performing the CSA vertical flame test — cables in cable trays, as described in CSA C22.2 No. 0.3-M-2001, Test Methods for Electrical Wires and Cables.
    4. Types OFN and OFC. Types OFN and OFC nonconduc‐ tive and conductive optical fiber cables shall be suitable for general-purpose use, with the exception of risers, plenums, and other spaces used for environmental air, and shall also be resist‐ ant to the spread of fire.Informational Note No. 1: One method of defining resistant to the spread of fire is that the cables do not spread fire to the top of the tray in the UL flame exposure, vertical tray flame test in ANSI/UL 1685-2010, Standard for Safety for Vertical-Tray Fire- Propagation and Smoke-Release Test for Electrical and Optical-Fiber Cables. The smoke measurements in the test method are not applicable.Another method of defining resistant to the spread of fire is for the damage (char length) not to exceed 1.5 m (4 ft 11 in.) when performing the CSA vertical flame test — cables in cable trays, as described in CSA C22.2 No. 0.3-M-2001, Test Methods for Electri‐ cal Wires and Cables.Informational Note No. 2: Cable types are listed in descending order of fire resistance rating. Within each fire resistance rating, nonconductive cable is listed first because it is often substituted for conductive cable.
    5. Circuit Integrity (CI) Cable or Electrical Circuit Protective System. Cables that are used for survivability of critical circuits under fire conditions shall meet either 770.179(E)(1) or (E)(2).Informational Note: The listing organization provides informa‐ tion for circuit integrity (CI) cable and electrical circuit protec‐ tive systems, including installation requirements necessary to maintain the fire rating.
      1. Circuit Integrity (CI) Cables. Circuit integrity (CI) cables specified in 770.179(A) through (D), and used for survivability of critical circuits, shall have an additional classification using the suffix “CI.” In order to maintain its listed fire rating, circuit integrity (CI) cable shall only be installed in free air.Informational Note: One method of defining circuit integrity (CI) cable is by establishing a minimum 2-hour fire resistance rating for the cable when tested in accordance with ANSI/ UL 2196-2006, Standard for Tests of Fire-Resistive Cable.
        Table 770.154(a) Applications of Listed Optical Fiber Cables in Buildings

        ApplicationsListed Optical Fiber Cable TypeOFNP, OFCPOFNR, OFCROFNG, OFCG, OFN, OFCIn ducts specifically fabricated for environmental air as described in 300.22(B)In fabricated ductsY*NNIn metal raceway that complies with 300.22(B)Y*Y*Y*In other spaces used for environmental air (plenums) as described in 300.22(C)In other spaces used for environmental airY*NNIn metal raceway that complies with 300.22(C)Y*Y*Y*In plenum communications racewaysY*NNIn plenum cable routing assembliesY*NNSupported by open metal cable traysY*NNSupported by solid bottom metal cable trays with solid metal coversY*Y*Y*In risersIn vertical runsY*Y*NIn metal racewaysY*Y*Y*In fireproof shaftsY*Y*Y*In plenum communications racewaysY*Y*NIn plenum cable routing assembliesY*Y*NIn riser communications racewaysY*Y*NIn riser cable routing assembliesY*Y*NIn one- and two-family dwellingsY*Y*Y*Within buildings in other than air- handling spaces and risersGeneralY*Y*Y*Supported by cable traysY*Y*Y*In distributing frames and cross- connect arraysY*Y*Y*In any raceway recognized in Chapter 3Y*Y*Y*In plenum communications racewaysY*Y*Y*In plenum cable routing assembliesY*Y*Y*In riser communications racewaysY*Y*Y*In riser cable routing assembliesY*Y*Y*In general-purpose communications racewaysY*Y*Y*In general-purpose cable routing assembliesY*Y*Y*Note: “N” indicates that the cable type shall not be permitted to be installed in the application.“Y*” indicates that the cable type shall be permitted to be installed in the application subject to the limitations described in 770.110 and 770.113. Informational Note No. 1: Part V of Article 770 covers installation methods within buildings. This table covers the applications of listed optical fiber cables in buildings. The definition of Point of Entrance is in 770.2.Informational Note No. 2: For information on the restrictions to the installation of optical fiber cables in ducts specifically fabricated for environmental air, see 770.113(B).•
        Table 770.154(b) Cable Substitutions
        imageCable Type Permitted SubstitutionsimageOFNP NoneOFCP OFNPOFNR OFNPOFCR OFNP, OFCP, OFNROFNG, OFN OFNP, OFNROFCG, OFC OFNP, OFCP, OFNR, OFCR, OFNG, OFN
        Nonconductive Conductive
        imageOFCPOFNPimagePlenum
        imageOFCROFNROFCG OFCOFNG OFNimageRiser
        imageGeneral purpose              
        imageA BCable A shall be permitted to be used in place of cable B.
        FIGURE 770.154 Cable Substitution Hierarchy.
        Table 770.179 Cable Markings
        imageCable Marking TypeimageOFNP Nonconductive optical fiber plenum cableOFCP Conductive optical fiber plenum cableOFNR Nonconductive optical fiber riser cableOFCR Conductive optical fiber riser cableOFNG Nonconductive optical fiber general- purpose cableOFCG Conductive optical fiber general-purpose cableOFN Nonconductive optical fiber general- purpose cableOFC Conductive optical fiber general-purpose cable
      2. Fire-Resistive Cables. Cables specified in 770.179(A) through (D) and 770.179(E)(1) that are part of an electrical circuit protective system shall be fire-resistive cable and identi‐ fied with the protective system number on the product or on the smallest unit container in which the product is packaged and installed in accordance with the listing of the protective system.Informational Note No. 1: One method of defining an electrical circuit protective system is by establishing a minimum 2-hour fire resistance rating for the system when tested in accordance with UL Subject 1724, Outline of Investigation for Fire Tests for Elec‐ trical Circuit Protective Systems.Informational Note No. 2: The listing organization provides information for electrical circuit protective systems (FHIT), including installation requirements for maintaining the fire rating.
    6. Field-Assembled Optical Fiber Cables. Field-assembled optical fiber cable shall comply with 770.179(F)(1) through (4).
    1. The specific combination of jacket and optical fibers intended to be installed as a field-assembled optical fiber cable shall be one of the types in 770.179(A), (B), or (D) and shall be marked in accordance with Table 770.179.
    2. The jacket of a field-assembled optical fiber cable shall have a surface marking indicating the specific optical fibers with which it is identified for use.
    3. The optical fibers shall have a permanent marking, such as a marker tape, indicating the jacket with which they are identified for use.
    4. The jacket without fibers shall meet the listing require‐ ments for communications raceways in 800.182(A), (B), or (C) in accordance with the cable marking.
  2. Grounding Devices. Where bonding or grounding is required, devices used to connect a shield, a sheath, or non– current-carrying metallic members of a cable to a bonding conductor or grounding electrode conductor shall be listed or be part of listed equipment.

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