ARTICLE 725

Class 1, Class 2, and Class 3 Remote- Control, Signaling, and Power-Limited Circuits

Part I. General

Scope. This article covers remote-control, signaling, and power-limited circuits that are not an integral part of a device or of utilization equipment.Informational Note: The circuits described herein are character‐ ized by usage and electrical power limitations that differentiate them from electric light and power circuits; therefore, alterna‐ tive requirements to those of Chapters 1 through 4 are given with regard to minimum wire sizes, ampacity adjustment and correction factors, overcurrent protection, insulation require‐ ments, and wiring methods and materials.
Definitions.Abandoned Class 2, Class 3, and PLTC Cable. Installed Class 2, Class 3, and PLTC cable that is not terminated at equipment and not identified for future use with a tag.Circuit Integrity (CI) Cable. Cable(s) used for remote-control, signaling, or power-limited systems that supply critical circuits to ensure survivability for continued circuit operation for a specified time under fire conditions.Class 1 Circuit. The portion of the wiring system between the load side of the overcurrent device or power-limited supply and the connected equipment.Informational Note: See 725.41 for voltage and power limita‐ tions of Class 1 circuits.Class 2 Circuit. The portion of the wiring system between the load side of a Class 2 power source and the connected equip‐ ment. Due to its power limitations, a Class 2 circuit considers safety from a fire initiation standpoint and provides acceptable protection from electric shock.Class 3 Circuit. The portion of the wiring system between the load side of a Class 3 power source and the connected equip‐ ment. Due to its power limitations, a Class 3 circuit considers
safety from a fire initiation standpoint. Since higher levels of voltage and current than for Class 2 are permitted, additional safeguards are specified to provide protection from an electric shock hazard that could be encountered.Power-Limited Tray Cable (PLTC). A factory assembly of two or more insulated conductors rated at 300 V, with or without associated bare or insulated equipment grounding conductors, under a nonmetallic jacket.
Other Articles. Circuits and equipment shall comply with the articles or sections listed in 725.3(A) through (N). Only those sections of Article 300 referenced in this article shall apply to Class 1, Class 2, and Class 3 circuits.

Number and Size of Conductors in Raceway.Section 300.17.
Spread of Fire or Products of Combustion. Installation of Class 1, Class 2, and Class 3 circuits shall comply with 300.21.
Ducts, Plenums, and Other Air-Handling Spaces. Class 1, Class 2, and Class 3 circuits installed in ducts, plenums, or other space used for environmental air shall comply with 300.22.Exception No. 1: Class 2 and Class 3 cables selected in accordance with Table 725.154 and installed in accordance with 725.135(B) and 300.22(B), Exception shall be permitted to be installed in ducts specifi‐ cally fabricated for environmental air.
Exception No. 2: Class 2 and Class 3 cables selected in accordance withTable 725.154 and installed in accordance with 725.135(C) shall be permitted to be installed in other spaces used for environmental air (plenums).
Hazardous (Classified) Locations. Articles 500 through516 and Article 517, Part IV, where installed in hazardous (classified) locations.
Cable Trays. Article 392, where installed in cable tray.
Motor Control Circuits. Article 430, Part VI, where tapped from the load side of the motor branch-circuit protective device(s) as specified in 430.72(A).
Instrumentation Tray Cable. See Article 727.
Raceways Exposed to Different Temperatures. Installa‐ tions shall comply with 300.7(A).
Vertical Support for Fire-Rated Cables and Conductors. Vertical installations of circuit integrity (CI) cables and conduc‐ tors installed in a raceway or conductors and cables of electrical circuit protective systems shall be installed in accordance with 300.19.
Bushing. A bushing shall be installed where cables emerge from raceway used for mechanical support or protection in accordance with 300.15(C).
Installation of Conductors with Other Systems. Installa‐ tions shall comply with 300.8.
Corrosive, Damp, or Wet Locations. Class 2 and Class 3 cables installed in corrosive, damp, or wet locations shall comply with the applicable requirements in 110.11, 300.5(B), 300.6, 300.9, and 310.10(G).N
Cable Routing Assemblies. Class 2, Class 3, and Type PLTC cables shall be permitted to be installed in plenum cablerouting assemblies, riser cable routing assemblies, and general- purpose cable routing assemblies selected in accordance with Table 800.154(c), listed in accordance with the provisions of 800.182, and installed in accordance with 800.110(C) and 800.113.N
Communications Raceways. Class 2, Class 3, and Type PLTC cables shall be permitted to be installed in plenum communications raceways, riser communications raceways, and general-purpose communications raceways selected in accord‐ ance with the provisions of Table 800.154(b), listed in accord‐ ance with 800.182, and installed in accordance with 800.113 and 362.24 through 362.56, where the requirements applicable to electrical nonmetallic tubing (ENT) apply.

725.21 Access to Electrical Equipment Behind Panels Designed to Allow Access. Access to electrical equipment shall not be denied by an accumulation of wires and cables that prevents removal of panels, including suspended ceiling panels.

Mechanical Execution of Work. Class 1, Class 2, and Class 3 circuits shall be installed in a neat and workmanlike manner. Cables and conductors 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 suppor‐ ted by straps, staples, hangers, cable ties, or similar fittings designed and installed so as not to damage the cable. The installation shall also comply with 300.4(D).
Abandoned Cables. The accessible portion of aban‐ doned Class 2, Class 3, and PLTC cables shall be removed. Where cables are identified for future use with a tag, the tag shall be of sufficient durability to withstand the environment involved.

Class 1, Class 2, and Class 3 Circuit Identification. Class 1, Class 2, and Class 3 circuits shall be identified at termi‐ nal and junction locations in a manner that prevents uninten‐ tional interference with other circuits during testing and servicing.
Safety-Control Equipment.

Remote-Control Circuits. Remote-control circuits for safety-control equipment shall be classified as Class 1 if the fail‐ ure of the equipment to operate introduces a direct fire or life hazard. Room thermostats, water temperature regulating devi‐ ces, and similar controls used in conjunction with electrically controlled household heating and air conditioning shall not be considered safety-control equipment.
Physical Protection. Where damage to remote-control circuits of safety-control equipment would introduce a hazard, as covered in 725.31(A), all conductors of such remote-control circuits shall be installed in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical metallic tubing, Type MI cable, or Type MC cable, or be otherwise suita‐ bly protected from physical damage.

725.35 Class 1, Class 2, and Class 3 Circuit Requirements. A remote-control, signaling, or power-limited circuit shall comply with the following parts of this article:

Class 1 Circuits: Parts I and II
Class 2 and Class 3 Circuits: Parts I and III

Part II. Class 1 Circuits

725.41 Class 1 Circuit Classifications and Power Source Requirements. Class 1 circuits shall be classified as either Class 1 power-limited circuits where they comply with the power limitations of 725.41(A) or as Class 1 remote-control and signaling circuits where they are used for remote-control or signaling purposes and comply with the power limitations of 725.41(B).

Class 1 Power-Limited Circuits. These circuits shall be supplied from a source that has a rated output of not more than 30 volts and 1000 volt-amperes.
1. Class 1 Transformers. Transformers used to supply power- limited Class 1 circuits shall comply with the applicable sections within Parts I and II of Article 450.
2. Other Class 1 Power Sources. Power sources other than transformers shall be protected by overcurrent devices rated at not more than 167 percent of the volt-ampere rating of the source divided by the rated voltage. The overcurrent devices shall not be interchangeable with overcurrent devices of higher ratings. The overcurrent device shall be permitted to be an integral part of the power supply.

To comply with the 1000 volt-ampere limitation of 725.41(A), the maximum output (VA max) of power sources other than transformers shall be limited to 2500 volt-amperes, and the product of the maximum current (I max) and maximum voltage (V max) shall not exceed 10,000 volt-amperes. These ratings shall be determined with any overcurrent-protective device bypassed.

Class 1 Circuit Overcurrent Device Location. Overcur‐ rent devices shall be located as specified in 725.45(A), (B), (C), (D), or (E).
1. Point of Supply. Overcurrent devices shall be located at the point where the conductor to be protected receives its supply.
2. Feeder Taps. Class 1 circuit conductors shall be permitted to be tapped, without overcurrent protection at the tap, where the overcurrent device protecting the circuit conductor is sized to protect the tap conductor.
3. Branch-Circuit Taps. Class 1 circuit conductors 14 AWG and larger that are tapped from the load side of the overcur‐ rent protective device(s) of a controlled light and power circuit shall require only short-circuit and ground-fault protection and shall be permitted to be protected by the branch-circuit over‐ current protective device(s) where the rating of the protective device(s) is not more than 300 percent of the ampacity of the Class 1 circuit conductor.
4. Primary Side of Transformer. Class 1 circuit conductors supplied by the secondary of a single-phase transformer having only a 2-wire (single-voltage) secondary shall be permitted to be protected by overcurrent protection provided on the primary side of the transformer, provided this protection is in accordance with 450.3 and does not exceed the value deter‐ mined by multiplying the secondary conductor ampacity by the secondary-to-primary transformer voltage ratio. Transformer secondary conductors other than 2-wire shall not be considered to be protected by the primary overcurrent protection.VA maxis the maximum volt-ampere output after one minute
5. Input Side of Electronic Power Source. Class 1 circuit conductors supplied by the output of a single-phase, listed elec‐
of operation regardless of load and with overcurrent protectionbypassed, if used. Current-limiting impedance shall not be bypassed when determining VA max.I max is the maximum output current under any noncapaci‐ tive load, including short circuit, and with overcurrent protec‐ tion bypassed, if used. Current-limiting impedance should not be bypassed when determining I max. Where a current-limiting impedance, listed for the purpose or as part of a listed product, is used in combination with a stored energy source, for exam‐ ple, storage battery, to limit the output current, I max limits apply after 5 seconds.V max is the maximum output voltage regardless of load with rated input applied.(B) Class 1 Remote-Control and Signaling Circuits. These circuits shall not exceed 600 volts. The power output of the source shall not be required to be limited.725.43 Class 1 Circuit Overcurrent Protection. Overcurrent protection for conductors 14 AWG and larger shall be provided in accordance with the conductor ampacity, without applying the ampacity adjustment and correction factors of 310.15 to the ampacity calculation. Overcurrent protection shall not exceed 7 amperes for 18 AWG conductors and 10 amperes for 16 AWG.Exception: Where other articles of this Code permit or require other over‐ current protection.Informational Note: For example, see 430.72 for motors, 610.53 for cranes and hoists, and 517.74(B) and 660.9 for X-ray equip‐ ment.tronic power source, other than a transformer, having only a 2-wire (single-voltage) output for connection to Class 1 circuits shall be permitted to be protected by overcurrent protection provided on the input side of the electronic power source, provided this protection does not exceed the value determined by multiplying the Class 1 circuit conductor ampacity by the output-to-input voltage ratio. Electronic power source outputs, other than 2-wire (single voltage), shall not be considered to be protected by the primary overcurrent protection.
Class 1 Circuit Wiring Methods. Class 1 circuits shall be installed in accordance with Part I of Article 300 and with the wiring methods from the appropriate articles in Chapter 3.

Exception No. 1: The provisions of 725.48 through 725.51 shall be permitted to apply in installations of Class 1 circuits.

Exception No. 2: Methods permitted or required by other articles of this Code shall apply to installations of Class 1 circuits.

Conductors of Different Circuits in the Same Cable, Cable Tray, Enclosure, or Raceway. Class 1 circuits shall be permitted to be installed with other circuits as specified in 725.48(A) and (B).
1. Two or More Class 1 Circuits. Class 1 circuits shall be permitted to occupy the same cable, cable tray, enclosure, or raceway without regard to whether the individual circuits are alternating current or direct current, provided all conductors are insulated for the maximum voltage of any conductor in the cable, cable tray, enclosure, or raceway.
2. Class 1 Circuits with Power-Supply Circuits. Class 1 circuits shall be permitted to be installed with power-supply conductors as specified in 725.48(B)(1) through (B)(4).
  1. In a Cable, Enclosure, or Raceway. Class 1 circuits and power-supply circuits shall be permitted to occupy the same cable, enclosure, or raceway only where the equipment powered is functionally associated.
  2. In Factory- or Field-Assembled Control Centers. Class 1 circuits and power-supply circuits shall be permitted to be installed in factory- or field-assembled control centers.
  3. In a Manhole. Class 1 circuits and power-supply circuits shall be permitted to be installed as underground conductors in a manhole in accordance with one of the following:
1. The power-supply or Class 1 circuit conductors are in a metal-enclosed cable or Type UF cable.
2. The conductors are permanently separated from the power-supply conductors by a continuous firmly fixed nonconductor, such as flexible tubing, in addition to the insulation on the wire.
3. The conductors are permanently and effectively separa‐ ted from the power supply conductors and securely fastened to racks, insulators, or other approved supports.
4. In Cable Trays. Installations in cable trays shall comply with 725.48(B)(4)(1) or (B)(4)(2).
1. Class 1 circuit conductors and power-supply conductors not functionally associated with the Class 1 circuit conductors shall be separated by a solid fixed barrier of a material compatible with the cable tray.
2. Class 1 circuit conductors and power-supply conductors not functionally associated with the Class 1 circuit conductors shall be permitted to be installed in a cable tray without barriers where all of the conductors are installed with separate multiconductor Type AC, Type MC, Type MI, or Type TC cables and all the conduc‐ tors in the cables are insulated at 600 volts or greater.
Class 1 Circuit Conductors.

Sizes and Use. Conductors of sizes 18 AWG and 16 AWG shall be permitted to be used, provided they supply loads that do not exceed the ampacities given in 402.5 and are installed in a raceway, an approved enclosure, or a listed cable. Conduc‐ tors larger than 16 AWG shall not supply loads greater than the ampacities given in 310.15. Flexible cords shall comply with Article 400.
Insulation. Insulation on conductors shall be rated for the system voltage and not less than 600 volts. Conductors larger than 16 AWG shall comply with Article 310. Conductors in sizes 18 AWG and 16 AWG shall be Type FFH-2, KF-2, KFF-2, PAF, PAFF, PF, PFF, PGF, PGFF, PTF, PTFF, RFH-2, RFHH-2, RFHH-3, SF-2, SFF-2, TF, TFF, TFFN, TFN, ZF, or ZFF. Conduc‐ tors with other types and thicknesses of insulation shall be permitted if listed for Class 1 circuit use.

Number of Conductors in Cable Trays and Raceway, and Ampacity Adjustment.
1. Class 1 Circuit Conductors. Where only Class 1 circuit conductors are in a raceway, the number of conductors shall be determined in accordance with 300.17. The ampacity adjust‐ ment factors given in 310.15(B)(3)(a) shall apply only if suchconductors carry continuous loads in excess of 10 percent of the ampacity of each conductor.
2. Power-Supply Conductors and Class 1 Circuit Conductors. Where power-supply conductors and Class 1 circuit conductors are permitted in a raceway in accordance with 725.48, the number of conductors shall be determined in accordance with300.17. The ampacity adjustment factors given in 310.15(B)(3)(a) shall apply as follows:
  1. To all conductors where the Class 1 circuit conductors carry continuous loads in excess of 10 percent of the ampacity of each conductor and where the total number of conductors is more than three
  2. To the power-supply conductors only, where the Class 1 circuit conductors do not carry continuous loads in excess of 10 percent of the ampacity of each conductor and where the number of power-supply conductors is more than three
3. Class 1 Circuit Conductors in Cable Trays. Where Class 1 circuit conductors are installed in cable trays, they shall comply with the provisions of 392.22 and 392.80(A).
Circuits Extending Beyond One Building. Class 1 circuits that extend aerially beyond one building shall also meet the requirements of Article 225.

Part III. Class 2 and Class 3 Circuits

725.121 Power Sources for Class 2 and Class 3 Circuits.

Power Source. The power source for a Class 2 or a Class 3 circuit shall be as specified in 725.121(A)(1), (A)(2), (A)(3), (A)(4), or (A)(5):Informational Note No. 1: Informational Note Figure 725.121, No. 1 illustrates the relationships between Class 2 or Class 3 power sources, their supply, and the Class 2 or Class 3 circuits.Informational Note No. 2: Table 11(A) and Table 11(B) in Chapter 9 provide the requirements for listed Class 2 and Class 3 power sources.
1. A listed Class 2 or Class 3 transformer
2. A listed Class 2 or Class 3 power supply
3. Other listed equipment marked to identify the Class 2 or Class 3 power sourceException No. 1 to (3): Thermocouples shall not require listing as a Class 2 power source.Exception No. 2 to (3): Limited power circuits of listed equipment where these circuits have energy levels rated at or below the limits established in Chapter 9, Table 11(A) and Table 11(B).Informational Note: Examples of other listed equipment are as follows:
  1. A circuit card listed for use as a Class 2 or Class 3 power source where used as part of a listed assembly
  2. A current-limiting impedance, listed for the purpose, or part of a listed product, used in conjunction with a non– power-limited transformer or a stored energy source, for example, storage battery, to limit the output current
  3. A thermocouple
  4. Limited voltage/current or limited impedance secondary communications circuits of listed industrial control equip‐ ment
1. Listed audio/video information technology (computer), communications, and industrial equipment limited-power circuits.Informational Note: One way to determine applicable requirements for listing of information technology (computer) equipment is to refer to UL 60950-1-2011, Standard for Safety of Information Technology Equipment. Another way to determine applicable requirements for listing of audio/video, information and communication technology equipment is to refer to UL 62368-1-2014, Safety of audio/video, information and communication technol‐ ogy equipment. Typically such circuits are used to intercon‐ nect data circuits for the purpose of exchanging information data. One way to determine applicable requirements for listing of industrial equipment is to refer to UL 61010-2-201, Safety requirements for electrical equipment for measurement, control, and laboratory use –Part 2-201: Particular requirements for control equipment, and/or UL 61800-5-1, Adjustable speed electrical power drive systems – Part 5-1: Safety requirements –Electrical, thermal and energy.
2. A dry cell battery shall be considered an inherently limi‐ ted Class 2 power source, provided the voltage is 30 volts or less and the capacity is equal to or less than that availa‐ ble from series connected No. 6 carbon zinc cells.
Interconnection of Power Sources. Class 2 or Class 3 power sources shall not have the output connections paralleled or otherwise interconnected unless listed for such interconnec‐ tion.N
Marking. The power sources for limited power circuits in 725.121(A)(3) and limited power circuits for listed audio/ video information technology (equipment) and listed indus‐ trial equipment in 725.121(A)(4) shall have a label indicating the maximum voltage and current output for each connection point. The effective date shall be January 1, 2018.

725.124 Circuit Marking. The equipment supplying the circuits shall be durably marked where plainly visible to indi‐ cate each circuit that is a Class 2 or Class 3 circuit.

Class 2 or

Class 3 circuit—

725.133 through 725.179

Power source—

725.121(A)(1)

through (A)(5)

Class 2 or

Class 3 circuit—

725.133 through 725.179

Power source—

725.127

Class 2 or

Class 3 circuit—

725.133 through 725.179

725.130

Part III of Article 725

725.121(A)(1)

through (A)(5)

Supply (0 to 1000

volts ac or dc)

Power source— 725.121(A)(1)

through (A)(5)

725.127 Wiring Methods on Supply Side of the Class 2 or Class 3 Power Source. Conductors and equipment on the supply side of the power source shall be installed in accordance with the appropriate requirements of Chapters 1 through 4. Transformers or other devices supplied from electric light or power circuits shall be protected by an overcurrent device rated not over 20 amperes.

Informational Note Figure 725.121 No. 1 Class 2 and

Class 3 Circuits.

Exception: The input leads of a transformer or other power source supplying Class 2 and Class 3 circuits shall be permitted to be smaller than 14 AWG, but not smaller than 18 AWG if they are not over 305 mm (12 in.) long and if they have insulation that complies with 725.49(B).

725.130 Wiring Methods and Materials on Load Side of the Class 2 or Class 3 Power Source. Class 2 and Class 3 circuits on the load side of the power source shall be permitted to be installed using wiring methods and materials in accordance with either 725.130(A) or (B).

Class 1 Wiring Methods and Materials. Installation shall be in accordance with 725.46.Exception No. 1: The ampacity adjustment factors given in 310.15(B)(3)(a) shall not apply.Exception No. 2: Class 2 and Class 3 circuits shall be permitted to be reclassified and installed as Class 1 circuits if the Class 2 and Class 3 markings required in 725.124 are eliminated and the entire circuit is installed using the wiring methods and materials in accord‐ ance with Part II, Class 1 circuits.Informational Note: Class 2 and Class 3 circuits reclassified and installed as Class 1 circuits are no longer Class 2 or Class 3 circuits, regardless of the continued connection to a Class 2 or Class 3 power source.
Class 2 and Class 3 Wiring Methods. Conductors on the load side of the power source shall be insulated at not less than the requirements of 725.179 and shall be installed in accord‐ ance with 725.133 and 725.154.

Exception No. 1: As provided for in 620.21 for elevators and similar equipment.

Exception No. 2: Other wiring methods and materials installed in accordance with the requirements of 725.3 shall be permitted to extend or replace the conductors and cables described in 725.179 and permit‐ ted by 725.130(B).

Exception No. 3: Bare Class 2 conductors shall be permitted as part of a listed intrusion protection system where installed in accordance with the listing instructions for the system.

725.133 Installation of Conductors and Equipment in Cables, Compartments, Cable Trays, Enclosures, Manholes, Outlet Boxes, Device Boxes, Raceways, and Cable Routing Assemblies for Class 2 and Class 3 Circuits. Conductors and equipment for Class 2 and Class 3 circuits shall be installed in accordance with 725.135 through 725.144.

Installation of Class 2, Class 3, and PLTC Cables. Installation of Class 2, Class 3, and PLTC cables shall comply with 725.135(A) through (M).
1. Listing. Class 2, Class 3, and PLTC cables installed in buildings shall be listed.
2. Ducts Specifically Fabricated for Environmental Air. The following wires and cables shall be permitted in ducts specifi‐ cally fabricated for environmental air as described in 300.22(B) if directly associated with the air distribution system:
  1. Types CL2P and CL3P cables in lengths as short as practi‐ cable to perform the required function
  2. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC cables 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 CL2P and CL3P cables
  2. Types CL2P and CL3P cables installed in plenum commu‐ nications raceways
  3. Types CL2P and CL3P cables installed in plenum cable routing assemblies
  4. Types CL2P and CL3P cables and plenum communica‐ tions raceways supported by open metallic cable trays or cable tray systems
  5. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC cables installed in raceways that are installed in compliance with 300.22(C)
  6. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC cables supported by solid bottom metal cable trays with solid metal covers in other spaces used for envi‐ ronmental air (plenums) as described in 300.22(C)
  7. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC cables installed in plenum communications raceways, riser communications raceways, and general- purpose communications raceways supported by solid bottom metal cable trays with solid metal covers in other spaces used for environmental air (plenums) as described in 300.22(C)
4. Risers — Cables in Vertical Runs. The following cables shall be permitted in vertical runs penetrating one or more floors and in vertical runs in a shaft:
  1. Types CL2P, CL3P, CL2R, and CL3R cables
  2. Types CL2P, CL3P, CL2R, and CL3R cables installed in the following:
    1. Plenum communications raceways
    2. Plenum cable routing assemblies
    3. Riser communications raceways
    4. Riser cable routing assemblies
  Informational Note: See 300.21 for firestop requirements for floor penetrations.
5. Risers — Cables in Metal Raceways. The following cables shall be permitted in metal raceways in a riser having firestops at each floor:
  1. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC cables
  2. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC cables installed in the following:
    1. Plenum communications raceways
    2. Riser communications raceways
    3. General-purpose communications raceways
  Informational Note: See 300.21 for firestop requirements for floor penetrations.
6. Risers — Cables in Fireproof Shafts. The following shall be permitted to be installed in fireproof riser shafts having fire‐ stops at each floor:
  1. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC cables
  2. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables installed in the following:
    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 300.21 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 CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables
  2. Types CL2X and CL3X cables less than 6 mm (0.25 in.) in diameter
  3. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables installed in the following:
    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. Cables installed in cable trays outdoors shall be Type PLTC. The following cables shall be permitted to be supported by cable trays in buildings:
1. Types CM CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables
2. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables installed in the following:
  1. Plenum communications raceways
  2. Riser communications raceways
  3. General-purpose communications raceways
1. Cross-Connect Arrays. The following cables shall be permitted to be installed in cross-connect arrays:
  1. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables
  2. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables installed in the following:
    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. Industrial Establishments. In industrial establishments where the conditions of maintenance and supervision ensure that only qualified persons service the installation, Type PLTC cable shall be permitted in accordance with either (1) or (2) as follows:
  1. Where the cable is not subject to physical damage, Type PLTC cable that complies with the crush and impact requirements of Type MC cable and is identified as PLTC- ER for such use shall be permitted to be exposed between the cable tray and the utilization equipment or device. The cable shall be continuously supported and protected against physical damage using mechanical protection such as dedicated struts, angles, or channels. The cable
    shall be supported and secured at intervals not exceeding1.8 m (6 ft). Where not subject to physical damage, Type PLTC-ER cable shall be permitted to transition between cable trays and between cable trays and utiliza‐ tion equipment or devices for a distance not to exceed 1.8 m (6 ft) without continuous support. The cable shall be mechanically supported where exiting the cable tray to ensure that the minimum bending radius is not excee‐ ded.
  2. Type PLTC cable, with a metallic sheath or armor in accordance with 725.179(E), shall be permitted to be installed exposed. The cable shall be continuously supported and protected against physical damage using mechanical protection such as dedicated struts, angles, or channels. The cable shall be secured at intervals not exceeding 1.8 m (6 ft).
3. Other Building Locations. The following wires and cables shall be permitted to be installed in building locations other than the locations covered in 725.135(B) through (I):
  1. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables
  2. A maximum of 3 m (10 ft) of exposed Type CL2X wires and cables in nonconcealed spaces
  3. A maximum of 3 m (10 ft) of exposed Type CL3X wires and cables in nonconcealed spaces
  4. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables installed in the following:
    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
  5. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC cables installed in raceways recognized in Chapter 3
  6. Type CMUC undercarpet communications wires and cables installed under carpet, modular flooring, and planks
4. Multifamily Dwellings. The following wires and cables shall be permitted to be installed in multifamily dwellings in locations other than the locations covered in 725.135(B) through (I):
  1. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC wires and cables
  2. Type CL2X wires and cables less than 6 mm ( 1∕4 in.) in diameter in nonconcealed spaces
  3. Type CL3X wires and cables less than 6 mm ( 1∕4 in.) in diameter in nonconcealed spaces
  4. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC wires and cables installed in the following:
    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
  5. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC wires and cables installed in raceways recog‐ nized in Chapter 3
  6. Type CMUC undercarpet communications wires and cables installed under carpet, modular flooring, and planks
5. One- and Two-Family Dwellings. The following wires and cables shall be permitted to be installed in one- and two-family dwellings in locations other than the locations covered in 725.135(B) through (I):
1. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC wires and cables
2. Type CL2X wires and cables less than 6 mm ( 1∕4 in.) in diameter
3. Type CL3X wires and cables less than 6 mm ( 1∕4 in.) in diameter
4. Communications wires and Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, and PLTC cables installed in the follow‐ ing:
  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
5. Types CL2P, CL3P, CL2R, CL3R, CL2, CL3, CL2X, CL3X, and PLTC wires and cables installed in raceways recog‐ nized in Chapter 3
6. Type CMUC undercarpet communications wires and cables installed under carpet, modular flooring, and planks
Separation from Electric Light, Power, Class 1, Non– Power-Limited Fire Alarm Circuit Conductors, and Medium- Power Network-Powered Broadband Communications Cables.

General. Cables and conductors of Class 2 and Class 3 circuits shall not be placed in any cable, cable tray, compart‐ ment, enclosure, manhole, outlet box, device box, raceway, or similar fitting with conductors of electric light, power, Class 1, non–power-limited fire alarm circuits, and medium-power network-powered broadband communications circuits unless permitted by 725.136(B) through (I).
Separated by Barriers. Class 2 and Class 3 circuits shall be permitted to be installed together with the conductors of elec‐ tric light, power, Class 1, non–power-limited fire alarm and medium power network-powered broadband communications circuits where they are separated by a barrier.
Raceways Within Enclosures. In enclosures, Class 2 and Class 3 circuits shall be permitted to be installed in a raceway to separate them from Class 1, non–power-limited fire alarm and medium-power network-powered broadband communications circuits.
Associated Systems Within Enclosures. Class 2 and Class 3 circuit conductors in compartments, enclosures, device boxes, outlet boxes, or similar fittings shall be permitted to be instal‐ led with electric light, power, Class 1, non–power-limited fire alarm, and medium-power network-powered broadband communications circuits where they are introduced solely to connect the equipment connected to Class 2 and Class 3 circuits, and where (1) or (2) applies:
1. The electric light, power, Class 1, non–power-limited fire alarm, and medium-power network-powered broadband communications circuit conductors are routed to main‐
  tain a minimum of 6 mm (0.25 in.) separation from the conductors and cables of Class 2 and Class 3 circuits.
2. The circuit conductors operate at 150 volts or less to ground and also comply with one of the following:
  1. The Class 2 and Class 3 circuits are installed using Type CL3, CL3R, or CL3P or permitted substitute cables, provided these Class 3 cable conductors extending beyond the jacket are separated by a mini‐ mum of 6 mm (0.25 in.) or by a nonconductive sleeve or nonconductive barrier from all other conductors.
  2. The Class 2 and Class 3 circuit conductors are instal‐ led as a Class 1 circuit in accordance with 725.41.
Enclosures with Single Opening. Class 2 and Class 3 circuit conductors entering compartments, enclosures, device boxes, outlet boxes, or similar fittings shall be permitted to be installed with Class 1, non–power-limited fire alarm and medium-power network-powered broadband communications circuits where they are introduced solely to connect the equip‐ ment connected to Class 2 and Class 3 circuits. Where Class 2 and Class 3 circuit conductors must enter an enclosure that is provided with a single opening, they shall be permitted to enter through a single fitting (such as a tee), provided the conductors are separated from the conductors of the other circuits by a continuous and firmly fixed nonconductor, such as flexible tubing.
Manholes. Underground Class 2 and Class 3 circuit conductors in a manhole shall be permitted to be installed with Class 1, non–power-limited fire alarm and medium-power network-powered broadband communications circuits where one of the following conditions is met:
1. The electric light, power, Class 1, non–power-limited fire alarm and medium-power network-powered broadband communications circuit conductors are in a metal- enclosed cable or Type UF cable.
2. The Class 2 and Class 3 circuit conductors are perma‐ nently and effectively separated from the conductors of other circuits by a continuous and firmly fixed noncon‐ ductor, such as flexible tubing, in addition to the insula‐ tion or covering on the wire.
3. The Class 2 and Class 3 circuit conductors are perma‐ nently and effectively separated from conductors of the other circuits and securely fastened to racks, insulators, or other approved supports.
Cable Trays. Class 2 and Class 3 circuit conductors shall be permitted to be installed in cable trays, where the conduc‐ tors of the electric light, Class 1, and non–power-limited fire alarm circuits are separated by a solid fixed barrier of a mate‐ rial compatible with the cable tray or where the Class 2 or Class 3 circuits are installed in Type MC cable.
In Hoistways. In hoistways, Class 2 or Class 3 circuit conductors shall be installed in rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible nonmetallic conduit, or electrical metallic tubing. For elevators or similar equipment, these conductors shall be permitted to be installed as provided in 620.21.
Other Applications. For other applications, conductors of Class 2 and Class 3 circuits shall be separated by at least 50 mm (2 in.) from conductors of any electric light, power, Class 1 non–power-limited fire alarm or medium power network- powered broadband communications circuits unless one of the following conditions is met:

Either (a) all of the electric light, power, Class 1, non– power-limited fire alarm and medium-power network- powered broadband communications circuit conductors or (b) all of the Class 2 and Class 3 circuit conductors are in a raceway or in metal-sheathed, metal-clad, non– metallic-sheathed, or Type UF cables.
All of the electric light, power, Class 1 non–power-limited fire alarm, and medium-power network-powered broad‐ band communications circuit conductors are perma‐ nently separated from all of the Class 2 and Class 3 circuit conductors by a continuous and firmly fixed nonconduc‐ tor, such as porcelain tubes or flexible tubing, in addition to the insulation on the conductors.

725.139 Installation of Conductors of Different Circuits in the Same Cable, Enclosure, Cable Tray, Raceway, or Cable Routing Assembly.

Two or More Class 2 Circuits. Conductors of two or more Class 2 circuits shall be permitted within the same cable, enclo‐ sure, raceway, or cable routing assembly.
Two or More Class 3 Circuits. Conductors of two or more Class 3 circuits shall be permitted within the same cable, enclo‐ sure, raceway, or cable routing assembly.
Class 2 Circuits with Class 3 Circuits. Conductors of one or more Class 2 circuits shall be permitted within the same cable, enclosure, raceway, or cable routing assembly with conductors of Class 3 circuits, provided that the insulation of the Class 2 circuit conductors in the cable, enclosure, raceway, or cable routing assembly is at least that required for Class 3 circuits.
Class 2 and Class 3 Circuits with Communications Circuits.
1. Classified as Communications Circuits. Class 2 and Class 3 circuit conductors shall be permitted in the same cable with communications circuits, in which case the Class 2 and Class 3 circuits shall be classified as communications circuits and shall be installed in accordance with the requirements of Article 800. The cables shall be listed as communications cables.
2. Composite Cables. Cables constructed of individually listed Class 2, Class 3, and communications cables under a common jacket shall be permitted to be classified as communi‐ cations cables. The fire resistance rating of the composite cable shall be determined by the performance of the composite cable.
Class 2 or Class 3 Cables with Other Circuit Cables. Jack‐ eted cables of Class 2 or Class 3 circuits shall be permitted in the same enclosure, cable tray, raceway, or cable routing assem‐ bly with jacketed cables of any of the following:
1. Power-limited fire alarm systems in compliance with Parts I and III of Article 760
2. Nonconductive and conductive optical fiber cables in compliance with Parts I and IV of Article 770
3. Communications circuits in compliance with Parts I and IV of Article 800
4. Community antenna television and radio distribution systems in compliance with Parts I and IV of Article 820
5. Low-power, network-powered broadband communica‐ tions in compliance with Parts I and IV of Article 830
Class 2 or Class 3 Conductors or Cables and Audio System Circuits. Audio system circuits described in 640.9(C), and installed using Class 2 or Class 3 wiring methods in compliance

with 725.133 and 725.154, shall not be permitted to be installed in the same cable, raceway, or cable routing assembly with Class 2 or Class 3 conductors or cables.

725.141 Installation of Circuit Conductors Extending Beyond One Building. Where Class 2 or Class 3 circuit conductors extend beyond one building and are run so as to be subject to accidental contact with electric light or power conductors oper‐ ating over 300 volts to ground, or are exposed to lightning on interbuilding circuits on the same premises, the requirements of the following shall also apply:

(1) Sections 800.44, 800.50, 800.53, 800.93, 800.100,

800.170(A), and 800.170(B) for other than coaxial conductors

(2) Sections 820.44, 820.93, and 820.100 for coaxial conduc‐ tors

Support of Conductors. Class 2 or Class 3 circuit conductors shall not be strapped, taped, or attached by any means to the exterior of any conduit or other raceway as a means of support. These conductors shall be permitted to be installed as permitted by 300.11(C)(2).N
Transmission of Power and Data. The requirements of 725.144(A) and (B) shall apply to Class 2 and Class 3 circuits that transmit power and data to a powered device. The require‐ ments of Parts I and III of Article 725 and 300.11 shall apply to Class 2 and Class 3 circuits that transmit power and data. The conductors that carry power for the data circuits shall be copper. The current in the power circuit shall not exceed the current limitation of the connectors.

Informational No. 1: One example of the use of cables that transmit power and data is the connection of closed-circuit TV cameras (CCTV).

Informational Note No. 2: The 8P8C connector is in widespread use with powered communications systems. These connectors are typically rated at 1.3 amperes maximum.

Use of Class 2 or Class 3 Cables to Transmit Power and Data. Where Types CL3P, CL2P, CL3R, CL2R, CL3, or CL2 transmit power and data, the following shall apply, as applica‐ ble:
1. The ampacity ratings in Table 725.144 shall apply at an ambient temperature of 30°C (86°F).
2. For ambient temperatures above 30°C (86°F), the correc‐ tion factors of 310.15(B)(2) shall apply.
Informational Note: One example of the use of Class 2 cables is a network of closed- circuit TV cameras using 24 AWG, 60°C rated, Type CL2R, Category 5e local area network (LAN) cables.
Use of Class 2-LP or Class 3-LP Cables to Transmit Power and Data. Types CL3P-LP, CL2P-LP, CL3R-LP, CL2R-LP, CL3-LP, or CL2-LP shall be permitted to supply power to equip‐ ment at a current level up to the marked ampere limit located immediately following the suffix LP and shall be permitted to transmit data to the equipment. The Class 2-LP and Class 3-LP cables shall comply with the following, as applicable:

Informational Note 1: The “(xxA)” following the suffix -LP indi‐ cates the ampacity of each conductor in a cable.

Informational Note 2: An example of a limited power (LP) cable is a cable marked Type CL2-LP(0.5A), 23 AWG. A Type CL2- LP(0.5), 23 AWG could be used in any location where a Type CL2 could be used; however, the LP cable would be suita‐ ble for carrying up to 0.5 A per conductor, regardless of the number of cables in a bundle. If used in a 7-cable bundle, the same cable could carry up to 1.2 amperes per conductor.

Cables with the suffix “-LP” shall be permitted to be installed in bundles, raceways, cable trays, communica‐ tions raceways, and cable routing assemblies.
Cables with the suffix “-LP” and a marked ampere level shall follow the substitution hierarchy of Table 725.154 and Figure 725.154(A) for the cable type without the suffix “LP” and without the marked ampere level.
System design shall be permitted by qualified persons under engineering supervision.

725.154 Applications of Listed Class 2, Class 3, and PLTC Cables. Class 2, Class 3, and PLTC cables shall comply with any of the requirements described in 725.154(A) through (C) and as indicated in Table 725.154.

Table 725.144 Ampacities of Each Conductor in Amperes in 4-Pair Class 2 or Class 3 Data Cables Based on Copper Conductors at an Ambient Temperature of 30°C (86°F) with All Conductors in All Cables Carrying Current, 60°C (140°F), 75°C (167°F), and 90°C (194°F) Rated Cables

AWG	Number of 4-Pair Cables in a Bundle
1	2–7	8–19	20–37	38–61	62–91	92–192
Temperature Rating	Temperature Rating	Temperature Rating	Temperature Rating	Temperature Rating	Temperature Rating	Temperature Rating
	60°C 75°C 90°C	60°C	75°C	90°C	60°C	75°C	90°C	60°C	75°C	90°C	60°C	75°C	90°C	60°C	75°C	90°C	60°C	75°C	90°C
26	1	1	1	1	1	1	0.7	0.8	1	0.5	0.6	0.7	0.4	0.5	0.6	0.4	0.5	0.6	NA	NA	NA
24	2	2	2	1	1.4	1.6	0.8	1	1.1	0.6	0.7	0.9	0.5	0.6	0.7	0.4	0.5	0.6	0.3	0.4	0.5
23	2.5	2.5	2.5	1.2	1.5	1.7	0.8	1.1	1.2	0.6	0.8	0.9	0.5	0.7	0.8	0.5	0.7	0.8	0.4	0.5	0.6
22	3	3	3	1.4	1.8	2.1	1	1.2	1.4	0.7	0.9	1.1	0.6	0.8	0.9	0.6	0.8	0.9	0.5	0.6	0.7

Note 1: For bundle sizes over 192 cables, or for conductor sizes smaller than 26 AWG, ampacities shall be permitted to be determined by qualified personnel under engineering supervision.

Note 2: Where only half of the conductors in each cable are carrying current, the values in the table shall be permitted to be increased by a factor of 1.4.

Informational Note: The conductor sizes in data cables in wide-spread use are typically 22–26 AWG.

Table 725.154 Applications of Listed Class 2, Class 3, CMUC, and PLTC Cables in Buildings

Applications	Cable Type
CL2P & CL3P	CL2R & CL3R	CL2 & CL3	CL2X & CL3X	CMUC	PLTC
In fabricated ducts as described in 300.22(B)	In fabricated ductsIn metal raceway that complies with 300.22(B)	Y* Y*	NY*	NY*	NY*	N N	NY*
In other spaces used for environmental air as described in 300.22(C)	In other spaces used for environmental air	Y*	N	N	N	N	N
In metal raceway that complies with 300.22(C)	Y*	Y*	Y*	Y*	N	Y*
In plenum communications raceways	Y*	N	N	N	N	N
In plenum cable routing assemblies	Y*	N	N	N	N	N
Supported by open metal cable trays	Y*	N	N	N	N	N
Supported by solid bottom metal cable trays with solid metal covers	Y*	Y*	Y*	Y*	N	N
In risers	In vertical runs	Y*	Y*	N	N	N	N
In metal raceways	Y*	Y*	Y*	Y*	N	Y*
In fireproof shafts	Y*	Y*	Y*	Y*	N	Y*
In plenum communications raceways	Y*	Y*	N	N	N	N
In plenum cable routing assemblies	Y*	Y*	N	N	N	N
In riser communications raceways	Y*	Y*	N	N	N	N
In riser cable routing assemblies	Y*	Y*	N	N	N	N
In one- and two-family dwellings	Y*	Y*	Y*	Y*	N	Y*
Within buildings in other than air-handling spaces and risers	General	Y*	Y*	Y*	Y*	N	YY
In one- and two-family dwellings	Y*	Y*	Y*	Y*	Y*
In multifamily dwellings	Y*	Y*	Y*	Y*	Y*	Y*
In nonconcealed spaces	Y*	Y*	Y*	Y*	Y*	Y*
Supported by cable trays	Y*	Y*	Y*	N	N	Y*
Under carpet	N	N	N	N	Y*	N
In cross-connect arrays	Y*	Y*	Y*	N	N	Y*
In any raceway recognized in Chapter 3	Y*	Y*	Y*	Y*	N	Y*
In plenum communications raceways	Y*	Y*	Y*	N	N	Y*
In plenum cable routing assemblies	Y*	Y*	Y*	N	N	Y*
In riser communications raceways	Y*	Y*	Y*	N	N	Y*
In riser cable routing assemblies	Y*	Y*	Y*	N	N	Y*
In general-purpose communications raceways	Y*	Y*	Y*	N	N	Y*
In general-purpose cable routing assemblies	Y*	Y*	Y*	N	N	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 725.130 through 725.143.

Class 2 and Class 3 Cable Substitutions. The substitutions for Class 2 and Class 3 cables listed in Table 725.154(A) and illustrated in Figure 725.154(A) shall be permitted. Where substitute cables are installed, the wiring requirements of Arti‐ cle 725, Parts I and III, shall apply.Informational Note: For information on Types CMP, CMR, CM, and CMX, see 800.179.
Class 2, Class 3, PLTC Circuit Integrity (CI) Cable or Elec‐ trical Circuit Protective System. Circuit integrity (CI) cable or a listed electrical circuit protective system shall be permitted for use in remote control, signaling, or power-limited systems that supply critical circuits to ensure survivability for continued circuit operation for a specified time under fire conditions.
Thermocouple Circuits. Conductors in Type PLTC cables used for Class 2 thermocouple circuits shall be permitted to be any of the materials used for thermocouple extension wire.

Table 725.154(A) Cable Substitutions

Cable Type Permitted Substitutions

CL3P CMP

CL2P CMP, CL3P

CL3R CMP, CL3P, CMR

CL2R CMP, CL3P, CL2P, CMR, CL3R PLTC

CL3 CMP, CL3P, CMR, CL3R, CMG, CM, PLTC

CL2 CMP, CL3P, CL2P, CMR, CL3R, CL2R, CMG, CM, PLTC, CL3

CL3X CMP, CL3P, CMR, CL3R, CMG, CM, PLTC, CL3, CMX

CL2X CMP, CL3P, CL2P, CMR, CL3R, CL2R, CMG, CM, PLTC, CL3, CL2, CMX, CL3X

CL2R

CL3R

CMR

CL2P

CL3P

CMP

Plenum

CL3X

CMX

CL2

CL3

CMG CM

CL2X

General purpose

PLTC

Riser

Dwelling

Type CM— Communications wires and cables

Type CL2 and CL3 — Class 2 and Class 3 remote-control, signaling, and power-limited cables

Type PLTC— Power-limited tray cable

A B

Cable A shall be permitted to be used in place of cable B.

FIGURE 725.154(A) Cable Substitution Hierarchy.

Part IV. Listing Requirements

725.170 Listing and Marking of Equipment for Power and Data Transmission. The listed power source for circuits inten‐ ded to provide power and data over Class 2 cables to remote equipment shall be as specified in 725.121(A)(1), (A)(2), (A)(3), or (A)(4). In accordance with 725.121(B), the power sources shall not have the output connections paralleled or otherwise interconnected, unless listed for such interconnec‐ tion. Powered devices connected to a circuit supplying data and power shall be listed. Marking of equipment output connec‐ tions shall be in accordance with 725.121(C).

725.179 Listing and Marking of Class 2, Class 3, and Type PLTC Cables. Class 2, Class 3, and Type PLTC cables, installed as wiring methods within buildings, shall be listed as resistant to the spread of fire and other criteria in accordance with 725.179(A) through (I) and shall be marked in accordance with 725.179(J).

Types CL2P and CL3P. Types CL2P and CL3P plenum cable shall be listed as suitable for use in ducts, plenums, and other space for environmental air and shall be listed as having adequate fire-resistant and low-smoke producing characteris‐ tics.Informational Note: One method of defining a cable that is low- smoke producing and fire resistant 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 maximum flame spread distance of1.52 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.
Types CL2R and CL3R. Types CL2R and CL3R riser cables shall be marked as Type CL2R or CL3R, respectively, and be listed as suitable for use in a vertical run in a shaft or from floor to floor and shall be listed as having fire-resistant charac‐ teristics capable 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 1666-2012, Test for Flame Propagation Height of Electrical and Optical-Fiber Cable Installed Vertically in Shafts.
Types CL2 and CL3. Types CL2 and CL3 cables shall be marked as Type CL2 or CL3, respectively, and be listed as suita‐ ble for general-purpose use, with the exception of risers, ducts, plenums, and other space used for environmental air, and shall be listed as resistant to the spread of fire.Informational Note: 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 for— cables in cable trays, as described in CSA C22.2 No. 0.3-M-2001, Test Methods for Electrical Wires and Cables.
Types CL2X and CL3X. Types CL2X and CL3X limited- use cables shall be marked as Type CL2X or CL3X, and be listed as suitable for use in dwellings and raceways and shall be listed as resistant to flame spread.Informational Note: One method of determining that cable is resistant to flame spread is by testing the cable to the VW-1 (vertical wire) flame test in ANSI/UL 1581-2011, Reference Stand‐ ard for Electrical Wires, Cables and Flexible Cords.
Type PLTC. Type PLTC nonmetallic-sheathed, power- limited tray cable shall be listed as being suitable for cable trays and shall consist of a factory assembly of two or more insulated conductors under a nonmetallic jacket. The insulated conduc‐ tors shall be 22 AWG through 12 AWG. The conductor material shall be copper (solid or stranded). Insulation on conductors shall be rated for 300 volts. The cable core shall be two or more parallel conductors, one or more group assemblies of twisted or parallel conductors, or a combination thereof. A metallic shield or a metallized foil shield with drain wire(s) shall be permitted to be applied over the cable core, over groups of conductors, or both. The cable shall be listed as resistant to the spread of fire. The outer jacket shall be a sunlight- and moisture-resistant nonmetallic material. Type PLTC cable used in a wet location shall be listed for use in wet locations or have a moisture-impervious metal sheath.Exception No. 1: Where a smooth metallic sheath, continuous corruga‐ ted metallic sheath, or interlocking tape armor is applied over the nonmetallic jacket, an overall nonmetallic jacket shall not be required. On metallic-sheathed cable without an overall nonmetallic jacket, the information required in 310.120 shall be located on the nonmetallic jacket under the sheath.Exception No. 2: Conductors in PLTC cables used for Class 2 thermo‐ couple circuits shall be permitted to be any of the materials used for ther‐ mocouple extension wire.Informational Note: 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 tray flame test for cables in cable trays, as described in CSA C22.2 No. 0.3-M-2001, Test Methods for Electrical Wires and Cables.
Circuit Integrity (CI) Cable or Electrical Circuit Protective System. Cables that are used for survivability of critical circuits under fire conditions shall meet either 725.179(F)(1) or (F)(2) as follows:
1. Circuit Integrity (CI) Cables. Circuit Integrity (CI) cables, specified in 725.179(A), (B), (C), and (E), and used for surviv‐ ability of critical circuits, shall have the additional classification using the suffix “CI.” Circuit integrity (CI) cables shall only be permitted to be installed in a raceway where specifically listed and marked as part of an electrical circuit protective system as covered in 725.179(F)(2).
2. Electrical Circuit Protective System. Cables specified in 725.179(A), (B), (C), (E), and (F)(1) that are part of an elec‐ trical circuit protective system shall be identified with the protective system number and hourly rating printed on the outer jacket of the cable and installed in accordance with the listing of the protective system.Informational Note No. 1: One method of defining circuit integ‐ rity (CI) cable or an electrical circuit protective system is by establishing a minimum 2-hour fire-resistive rating when tested in accordance with UL 2196-2012, Standard for Tests of Fire Resis‐ tive Cables.Informational Note No. 2: UL guide information for electrical circuit protective systems (FHIT) contains information on proper installation requirements to maintain the fire rating.
Class 2 and Class 3 Cable Voltage Ratings. Class 2 cables shall have a voltage rating of not less than 150 volts. Class 3 cables shall have a voltage rating of not less than 300 volts. Class 2 and Class 3 cables shall have a temperature rating of not less than 60°C (140°F).
Class 3 Single Conductors. Class 3 single conductors used as other wiring within buildings shall not be smaller than 18 AWG and shall be Type CL3. Conductor types described in 725.49(B) that are also listed as Type CL3 shall be permitted.Informational Note: 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 tray flame test for cables in cable trays, as described in CSA C22.2 No. 0.3-M-2001, Test Methods for Electrical Wires and Cables.N
Limited Power (LP) Cables. Limited power (LP) cables shall be listed as suitable for carrying power and data circuits up to a specified current limit for each conductor without exceeding the temperature rating of the cable where the cable is installed in cable bundles in free air or installed within a raceway, cable tray, or cable routing assembly. The cables shall be marked with the suffix “-LP” with the ampere limit located immediately following the suffix LP, where the current limit is in amperes per conductor.Informational Note: The ampere limit located immediately following the suffix LP is the ampacity of each conductor in a cable. For example, 1 ampere Class 2 limited-power cables would be marked CL2-LP (1.0A), CL2R-LP (1.0A), or CL2-LP (1.0A).•
Marking. Cables shall be marked in accordance with

310.120(A)(2), (A)(3), (A)(4), (A)(5), and Table 725.179(J).

Voltage ratings shall not be marked on the cables.

Informational Note: Voltage markings on cables may be misin‐ terpreted to suggest that the cables may be suitable for Class 1 electric light and power applications.

Exception: Voltage markings shall be permitted where the cable has multiple listings and a voltage marking is required for one or more of the listings.

Temperature rating shall be marked on the jacket of Class 2 and Class 3 cables that have a temperature rating exceeding 60°C (140°F).

727.1 ARTICLE 727 — INSTRUMENTATION TRAY CABLE: TYPE ITC

Table 725.179(J) Cable Marking

Cable Marking Type

CL3P Class 3 plenum cable

CL2P Class 2 plenum cable

CL3R Class 3 riser cable

CL2R Class 2 riser cable

PLTC Power-limited tray cable

CL3 Class 3 cable

CL2 Class 2 cable

CL3X Class 3 cable, limited use

CL2X Class 2 cable, limited use

Informational Note: Class 2 and Class 3 cable types are listed in descending order of fire resistance rating, and Class 3 cables are listed above Class 2 cables because Class 3 cables can substitute for Class 2 cables.

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