xcm

Article 336 Power and Control Tray Cable: Type TC Part I. General 336.1 Scope. This article covers the use, installation, and construction specifications for power and control tray cable, Type TC. ENHANCED CONTENT Collapse The basic standard to investigate power and control tray cable is ANSI/UL 127...

Article 336 Power and Control Tray Cable: Type TC Part I. General 336.1 Scope. This article covers the use, installation, and construction specifications for power and control tray cable, Type TC. ENHANCED CONTENT Collapse The basic standard to investigate power and control tray cable is ANSI/UL 1277, Electrical Power and Control Tray Cables with Optional Optical-Fiber Members. Summary information regarding listed power and control tray cable may be found in the UL Guide Information for Electrical Equipment, under category QPOR. 336.6 Listing Requirements. Type TC cables and associated fittings shall be listed. Part II. Installation 336.10 Uses Permitted. Type TC cable shall be permitted to be used as follows: (1) For power, lighting, control, and signal circuits. In cable trays, including those with mechanically discontinuous segments up to 300 mm (1 ft). In raceways. In outdoor locations supported by a messenger wire. For Class 1 circuits as permitted in Parts II and III of Article 725. For non-power-limited fire alarm circuits if conductors comply with the requirements of 760.49. Between a cable tray and the utilization equipment or device(s), provided all of the following apply: The cable is Type TC-ER. The cable is installed in industrial establishments where the conditions of maintenance and supervision ensure that only qualified persons service the installation. The cable is continuously supported and protected against physical damage using mechanical protection such as struts, angles, or channels. The cable complies with the crush and impact requirements of Type MC cable and is identified with the marking “TC–ER.” The cable is secured at intervals not exceeding 1.8 m (6 ft). Equipment grounding for the utilization equipment is provided by an equipment grounding conductor within the cable. In cables containing conductors sized 6 AWG or smaller, the equipment grounding conductor shall be provided within the cable or, at the time of installation, one or more insulated conductors shall be permanently identified as an equipment grounding conductor in accordance with 250.119(C). Exception to (7): Where not subject to physical damage, Type TC-ER shall be permitted to transition between cable trays and between cable trays and 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 exceeded. Type TC cable shall be resistant to moisture and corrosive agents where installed in wet locations. For one- and two-family dwelling units, Type TC-ER-JP cable containing conductors for both power and control circuits shall be permitted for branch circuits and feeders. Type TC-ER-JP cable used as interior wiring shall be installed per the requirements of Part II of Article 334 and where installed as exterior wiring shall be installed per the requirements of Part II of Article 340. Exception: Where used to connect a generator and associated equipment having terminals rated 75°C (140°F) or higher, the cable shall not be limited in ampacity by 334.80 or 340.80. Informational Note No. 1: See 725.136 for limitations on Class 2 or 3 circuits contained within the same cable with conductors of electric light, power, or Class 1 circuits. Direct buried, where identified for such use. In hazardous (classified) locations where specifically permitted by other articles in this Code. For service-entrance conductors where identified for such use and marked Type TC-ER. Informational Note No. 2: See 310.14(A)(3) for temperature limitation of conductors. ENHANCED CONTENT Collapse Specific types of tray cable are permitted to extend from a cable tray to a piece of equipment without the use of conduit. According to ANSI/UL 1277, Electrical Power and Control Tray Cables with Optional Optical-Fiber Members, cables suitable for use as exposed wiring between cable tray and the utilization equipment are surface-marked “Type TC-ER” (tray cable for exposed runs). The Exception to (7) permits TC-ER cable to exit a cable tray without continuous support for a maximum of 6 feet. However, extension from cable tray to cable tray or from cable tray to equipment is not allowed beyond 6 feet without continuous support. Power conductors and control conductors are often used to run between a generator and transfer switch, or between equipment of an HVAC system. Type TC-ER cable allows the power and control circuit conductors to occupy the same cable. 336.12 Uses Not Permitted. Type TC tray cable shall not be installed or used as follows: (1) Installed where it will be exposed to physical damage Installed outside a raceway or cable tray system, except as permitted in 336.10(4), 336.10(7), 336.10(9), and 336.10(10) Used where exposed to direct rays of the sun, unless identified as sunlight resistant 336.24 Bending Radius. Bends in Type TC cable shall be made so as not to damage the cable. For Type TC cable without metal shielding, the minimum bending radius shall be as follows: (1) Four times the overall diameter for cables 25 mm (1 in.) or less in diameter Five times the overall diameter for cables larger than 25 mm (1 in.) but not more than 50 mm (2 in.) in diameter Six times the overall diameter for cables larger than 50 mm (2 in.) in diameter Type TC cables with metallic shielding shall have a minimum bending radius of not less than 12 times the cable overall diameter. 336.80 Ampacity. The ampacity of Type TC tray cable shall be determined in accordance with 392.80(A) for 14 AWG and larger conductors, in accordance with 402.5 for 18 AWG through 16 AWG conductors where installed in cable trays, and in accordance with 310.14 where installed outside of cable trays, where permitted. Part III. Construction Specifications 336.100 Construction. A metallic sheath or armor as defined in 330.116 shall not be permitted either under or over the nonmetallic jacket. Metallic shield(s) shall be permitted over groups of conductors, under the outer jacket, or both. 336.104 Conductors. For ungrounded, grounded, and equipment grounding conductors, the conductor sizes shall be 14 AWG through 1000 kcmil copper, nickel, or nickel-coated copper and 12 AWG through 1000 kcmil aluminum or copper-clad aluminum. Insulation types shall be one of the types listed in Table 310.4(1) or Table 310.4(2) that is suitable for branch circuit and feeder circuits or one that is identified for such use. For control and signal conductors, the minimum conductor sizes shall be 18 AWG copper, nickel, or nickel-coated copper, 14 AWG copper-clad aluminum, and 12 AWG aluminum. Fire Alarm Systems. Where used for fire alarm systems, conductors shall also be in accordance with 760.49. Thermocouple Circuits. Conductors in Type TC cable used for thermocouple circuits in accordance with Part III of Article 724 shall also be permitted to be any of the materials used for thermocouple extension wire. Class 1 Circuit Conductors. Insulated conductors of 18 AWG and 16 AWG copper shall also be in accordance with 724.49. 336.116 Jacket. The outer jacket shall be a flame-retardant, nonmetallic material. 336.120 Marking. There shall be no voltage marking on a Type TC cable employing thermocouple extension wire. 336.130 Hazardous (Classified) Location Cable. Cable listed and marked Type TC-ER-HL shall comply with the following: (1) The overall nonmetallic jacket shall be suitable for the environment. The overall cable construction shall be es