Chapter 3 Wiring Methods and Materials

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ARTICLE 320 - ARMORED CABLE: lYPE AC 320.10 and legibly marked with the manufacturer's name or trademark. IV. Pull and Junction Boxes for Use on Systems over 600 Volts, Nominal 314.70 General. Where pull and junction boxes are used on systems over 600 volts, the installation shall comply with the provisions of Part IV and also with the following general provisions of this article: (1) Part I, 314.2, 314.3, and 314.4 (2) Part II, 314.15; 314.17; 314.20; 314.23(A), (B), or (G); 314.28(B); and 314.29 (3) Part III, 314.40(A) and (C) and 314.41 314.71 Size of Pull and Junction Boxes. Pull and junction boxes shall provide adequate space and dimensions for the installation of conductors, and they shall comply with the specific requirements of this section. Exception: Terminal housings supplied with motors shall comply with the provisions of 430.12. (A) For Straight Pulls. The length of the box shall not be less than 48 times the outside diameter, over sheath, of the largest shielded or lead-covered conductor or cable entering the box. The length shall not be less than 32 times the outside diameter of the largest nonshielded conductor or cable. (B) For Angle or U Pulls. (1) Distance to Opposite Wall. The distance between each cable or conductor entry inside the box and the opposite wall of the box shall not be less than 36 times the outside diameter, over sheath, of the largest cable or conductor. This distance shall be incmased for additional entries by the amount of the sum of the outside diameters, over sheath, of all other cables or conductor entries through the same wall of the box. Exception No.1: Where a conductor or cable entry is in the wall of a box opposite a removable cover, the distance from that wall to the cover shall be permitted to be not less than the bending radius for the conductors as provided in 300.34. Exception No.2: Where cables are nonshielded and not lead covered, the distance of 36 times the outside diameter shall be permitted to be reduced to 24 times the outside diameter. (2) Distance Between Entry and Exit. The distance between a cable or conductor entry and its exit from the box shall not be less than 36 times the outside diameter, over sheath, of that cable or conductor. Exception: Where cables are nonshielded and not lead covered, the distance of36 times the outside diameter shall be permitted to be reduced to 24 times the outside diameter. (C) Removable Sides. One or more sides of any pull box shall be removable. 314.72 Construction and Installation Requirements. (A) Corrosion Protection. Boxes shall be made of material inherently resistant to corrosion or shall be suitably protected, both internally and externally, by enameling, galvanizing, plating, or other means. (B) Passing Through Partitions. Suitable bushings, shields, or fittings having smooth, rounded edges shall be provided where conductors or cables pass through partitions and at other locations where necessary. (C) Complete Enclosure. Boxes shall provide a complete enclosure for the contained conductors or cables. (D) Wiring Is Accessible. Boxes shall be installed so that the wiring is accessible without removing any part of the building. Working space shall be provided in accordance with 110.34. (E) Suitable Covers. Boxes shall be closed by suitable covers securely fastened in place. Underground box covers that weigh over 45 kg (l00 Ib) shall be considered meeting this requirement. Covers for boxes shall be permanently marked "DANGER - HIGH VOLTAGE - KEEP OUT." The marking shall be on the outside of the box cover and shall be readily visible. Letters shall be block type and at least 13 mm (V2 in.) in height. (F) Suitable for Expected Handling. Boxes and their covers shall be capable of withstanding the handling to which they are likely to be subjected. I. General 320.1 Scope. This article covers the use, installation, and construction specifications for armored cable, Type AC. 320.2 Definition. Armored Cable, Type AC. A fabricated assembly of insulated conductors in a flexible metallic enclosure. See 320.100. II. Installation 320.10 Uses Permitted. Type AC cable shall be permitted as follows: 2008 Edition NATlO''lAL ELECTRICAL CODE 70-175
320.12 ARTICLE 320 - ARMORED CABLE: lYPE AC (I) Forf~¢t:J~rs and btaOGh ~lteQits in both exposed and concealed work (2) In cable trays (3) In dry locations (4) Embedded in plaster finish on brick or other masonry, except in damp or wet locations (5) To be run or fished in the air voids of masonry block or tile walls where such walls are not exposed or subject to excessive moisture or dampness FPN: The "Uses Permitted" is not an all-inclusive list. 320.12 Uses Not Permitted. Type AC cable shall not be used as follows: (1) Where subject to physical damage (2) In damp or wet locations (3) In air voids of masonry block or tile walls where such walls are exposed or subject to excessive moisture or dampness (4) Where exposed to corrosive fumes or vapors (5) Embedded in plaster finish on brick or other masonry in damp or wet locations 320.15 Exposed Work. Exposed runs of cable, except as provided in 300.11 (A), shall closely follow the surface of the building finish or of running boards. Exposed runs shall also be permitted to be installed on the underside of joists where supported at each joist and located so as not to be subject to physical damage. 320.17 Through or Parallel to Framing Members. Type AC cable shall be protected in accordance with 300.4(A), (C), and (D) where installed through or parallel to framing members. 320.23 In Accessible Attics. Type AC cables in accessible attics or roof spaces shall be installed as specified in 320.23(A) and (B). (A) Where Run Across the Top of Floor Joists. Where run across the top of floor joists, or within 2.1 m (7 ft) of floor or floor joists across the face of rafters or studding, in attics and roof spaces that are accessible, the cable shall be protected by substantial guard strips that are at least as high as the cable. Where this space is not accessible by permanent stairs or ladders, protection shall only be required within 1.8 m (6 ft) of the nearest edge of the scuttle hole or attic entrance. (B) Cable Installed Parallel to Framing Members. Where the cable is installed parallel to the sides of rafters, studs, or floor joists, neither guard strips nor running boards shall be required, and the installation shall also comply with 300.4(D). 320.24 Bending Radius. Bends in Type AC cable shall be made such that the cable is not damaged. The radius of the curve of the inner edge of any bend shall not be less than five times the diameter of the Type AC cable. 320.30 Securing and Supporting. (A) General. Type AC cable shall be supported and secured by staples, cable ties, straps, hangers, or similar fittings, designed and installed so as not to damage the cable. (B) Securing. Unless otherwise provided, Type AC cable shall be secured within 300 mm (12 in.) of every outlet box, junction box, cabinet, or fitting and at intervals not exceeding 1.4 m (4Vz ft) where installed on or across framing members. (C) Supporting. Unless otherwise provided, Type AC cable shall be supported at intervals not exceeding 1.4 m (4Vz ft). Horizontal runs of Type AC cable installed in wooden or metal framing members or similar supporting means shall be considered supported where such support does not exceed 1.4-m (4Vz-ft) intervals. (D) Unsupported Cables. Type AC cable shall be permitted to be unsupported where the cable complies with any of the following: (1) Is fished between access points through concealed spaces in finished buildings or structures and supporting is impracticable (2) Is not more than 600 mID (2 ft) in length at terminals where flexibility is necessary (3) Is not more than 1.8 m (6 ft) in length from the last point of cable support to the point of connection to a luminaire(s) or other electrical equipment and the cable and point of connection are within an accessible ceiling. For the purposes of this section, Type AC cable fittings shall be permitted as a means of cable support. 320.40 Boxes and Fittings. At all points where the armor ofAC cable terminates, a fitting shall be provided to protect wires from abrasion, unless the design of the outlet boxes or fittings is such as to afford equivalent protection, and, in addition, an insulating bushing or its equivalent protection shall be provided between the conductors and the armor. The connector or clamp by which the Type AC cable is fastened to boxes or cabinets shall be of such design that the insulating bushing or its equivalent will be visible for inspection. Where change is made from Type AC cable to other cable or raceway wiring methods, a box, fitting, or conduit body shall be installed at junction points as required in 300.15. 320.80 Ampacity. The ampacity shall be determined by 310.15. 70-176 NATIONAL ELECTRICAL CODE 2008 Edition
Page 1 and 2: CHAPTER 3 ARTICLE 300 - WIRING METH
Page 3 and 4: 300.5 ARTICLE 300 - WIRING METHODS
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Page 43 and 44: 314.4 ARTICLE 314 - OUTLET, DEVICE,
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Page 47 and 48: 314.24 ARTICLE 314 - OUTLET. DEVICE
Page 49: 314.30 ARTICLE 314-0UTLET, DEVICE.
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Page 55 and 56: 324.60 ARTICLE 326 - INTEGRATED GAS
Page 57 and 58: 328.100 ARTICLE 330 - METAL-CLAD CA
Page 59 and 60: 332.1 ARTICLE 332-MINERAL-INSULATED
Page 61 and 62: 334.12 ARTICLE 334-NONMETALLIC-SHEA
Page 63 and 64: 336.1 ARTICLE 336 - POWER AND CONTR
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Page 67 and 68: 342.28 ARTICLE 344-RIGID METAL COND
Page 69 and 70: 344.42 ARTICLE 348 - FLEXIBLE METAL
Page 71 and 72: 348.42 ARTICLE 350 - LIQUIDTIGHT FL
Page 73 and 74: 352.12 ARTICLE 352 - RIGID POLYVINY
Page 75 and 76: 352.60 ARTICLE 353 - HIGH DENSITY P
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Page 79 and 80: 355.22 ARTICLE 355 - REINFORCED THE
Page 81 and 82: 356.6 ARTICLE 356 - LIQUIDTIGHT FLE
Page 83 and 84: 358.22 ARTICLE 360 - FLEXIBLE METAL
Page 85 and 86: 362.1 ARTICLE 362 - ELECTRICAL NONM
Page 87 and 88: 366.1 ARTICLE 366 - AUXILIARY GUTTE
Page 89 and 90: 368.1 ARTICLE 368 - BUSWAYS (I) Sui
Page 91 and 92: 368.214 ARTICLE 370 - CABLEBUS IV.
Page 93 and 94: 372.4 ARTICLE 374 - CELLULAR METAL
Page 95 and 96: 376.12 ARTICLE 376-METAL WIREWAYS 3
Page 97 and 98: 378.30 ARTICLE 382 - NONMETALLIC EX
Page 99 and 100: 382.56 ARTICLE 384- STRUT-TIPE CHAN
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384.120 ARTICLE 386-SURFACE METAL R
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390.1 ARTICLE 390 - UNDERFLOOR RACE
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392.4 ARTICLE 392 - CABLE TRAYS the
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392.9 ARTICLE 392 - CABLE TRA YS si
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392.11 ARTICLE 392 - CABLE TRAYS Ta
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394.10 ARTICLE 394 - CONCEALED KNOB
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398.10 ARTICLE 398 - OPEN WIRING ON
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