BUSWAYS

70-273 363-14. Extensions. All extensions from flat cable assemblies shall be made by approved wiring methods, within the junction boxes, installed at either end of the flat cable assembly runs. 363-15. Supports. The flat cable assemblies shall be supported by means of their special design features, within the surface metal raceways. The surface metal raceways shall be supported as required for the specific raceway to be installed. 363-16. Rating. The rating of the branch circuit shall not exceed 30 amperes. 363-17. Marking. In addition to the provisions of Section 310-11, Type FC cable shall have the temperature rating durably marked on the surface at intervals not exceeding 24 inches (610 mm). 363-18. Protective Covers. Where a flat cable assembly is installed less than 8 feet (2.44 m) from the floor, it shall be protected by a metal cover identified for the use. 363-19. Identification. The grounded conductor shall be identified throughout its length by means of a distinctive and durable white or natural gray marking. 363-20. Terminal Block Identification. Terminal blocks identified for the use shall have distinctive and durable markings for color or word coding. The grounded conductor section shall have a white marking or other suitable designation. The next adjacent section of the terminal block shall have a black marking or other suitable designation. The next section shall have a red marking or other suitable designation. The final or outer section, opposite the grounded conductor section of the terminal block, shall have a blue marking or other suitable designation. ARTICLE 364 - BUSWAYS A. General Requirements 364-1. Scope. This article covers service-entrance, feeder, and branchcircuit busways and associated fittings. 364-2. Definition. For the purpose of this article, a busway is considered to be a grounded metal enclosure containing factory-mounted, bare or insulated conductors, which are usually copper or aluminum bars, rods, or tubes. (FPN): For cablebus, refer to Article 365. 364-3. Other Articles. Installations of busways shall comply with the applicable provisions of Article 300. 70-274 NATIONAL ELECTRICAL CODE 364-4. Use. (a) Use Permitted. Busways shall be installed only where they are located in the open and are visible. Exception No. 1: Busways shall be permitted to be installed behind panels if means of access are provided and if all the following conditions are met. a. No overcurrent devices are installed on the busway other than for individual fixtures or other loads. b. The space behind the access panels is not used for air-handling purposes. C. The busway is totally enclosed, nonventilating type. d. Busway is so installed that the joints between sections and fittings are accessible for maintenance purposes. Exception No. 2: Busways shall be permitted to be installed behind access panels in accordance with Section 300-22(c). (b) Use Prohibited. Busways shall not be installed (1) where subject to severe physical damage or corrosive vapors; (2) in hoistways; (3) in any hazardous (classified) location, unless specifically approved for such use [see Section 501-4(b)]; nor (4) outdoors or in wet or damp locations unless identified for such use. 364-5. Support. Busways shall be securely supported at intervals not exceeding 5 feet (1.52 m) unless otherwise designed and marked. 364-6. Through Walls and Floors. It shall be permissible to extend unbroken lengths of busway through dry walls. It shall be permissible to extend busways vertically through dry floors if totally enclosed (unventilated) where passing through and for a minimum distance of 6 feet (1.83 m) above the floor to provide adequate protection from physical damage. 364-7. Dead Ends. A dead end of a busway shall be closed. 364-8. Branches from Busways. Branches from busways shall be made with busways, rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, electrical nonmetallic tubing, flexible metal conduit, liquidtight flexible metal conduit, electrical metallic tubing, metal surface raceway, metal-clad cable, or listed bus drop cable; or with suitable cord assemblies approved for hard usage for the connection of portable equipment or for the connection of stationary equipment to facilitate their interchange. Flexible cord assembly connections shall be permitted to be made directly to the load end terminals of a busway plug-in device, provided a suitable tension take-up device is employed on the cord and the length of the cord from the busway plug-in device to the tension take-up device does not exceed 6 feet (1.83 m). Where a nonmetallic raceway is used, connection of equipment grounding conductors in the nonmetallic raceway to the busway shall comply with Sections 250-113 and 250-118. 364-9. Overcurrent Protection. Overcurrent protection shall be provided in accordance with Sections 364-10 through 364-14. ARTICLE 364 - BUSWAYS 70-275 364-10. Rating of Overcurrent Protection - Feeders. Where the allowable current rating of the busway does not correspond to a standard rating of the overcurrent device, the next higher rating shall be permitted. 364-11. Reduction in Ampacity Size of Busway. Overcurrent protection shall be required where busways are reduced in ampacity. Exception: For industrial establishments only, omission of overcurrent protection shall be permitted at points where busways are reduced in ampacity, provided that the length of the busway having the smaller ampacity does not exceed 50 feet (15.2 m) and has an ampacity at least equal to ¹/₃ the rating or setting of the overcurrent device next back on the line, and provided further that such busway is free from contact with combustible material. 364-12. Feeder or Branch Circuits. Where a busway is used as a feeder, devices or plug-in connections for tapping off feeder or branch circuits from the busway shall contain the overcurrent devices required for the protection of the feeder or branch circuits. The plug-in device shall consist of an externally operable circuit breaker or an externally operable fusible switch. Where such devices are mounted out of reach and contain disconnecting means, suitable means such as ropes, chains, or sticks shall be provided for operating the disconnecting means from the floor. Exception No. 1: As permitted in Section 240-21 for taps. Exception No. 2: For fixed or semi-fixed lighting fixtures, where the branch-circuit overcurrent device is part of the fixture cord plug on cordconnected fixtures. Exception No. 3: Where fixtures without cords are plugged directly into the busway and the overcurrent device is mounted on the fixture. 364-13. Rating of Overcurrent Protection - Branch Circuits. A busway shall be permitted as a branch circuit of any one of the types described in