160 lines
7.3 KiB
Markdown
160 lines
7.3 KiB
Markdown
---
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id:
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aliases:
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- nec-320
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tags:
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- authorship/other
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- destiny/uncertain
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- exclude-from-word-count
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- status/draft
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- topic/construction/electrical
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- type/media/reference
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title: "Article 320 Armored Cable: Type AC"
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---
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# Article 320 Armored Cable: Type AC
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## Part I. General
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### 320.1 Scope.
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This article covers the use, installation, and construction specifications for armored cable, Type AC.
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### 320.2 Definition.
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The definition in this section shall apply within this article and throughout the Code.
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Armored Cable, Type AC.
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A fabricated assembly of insulated conductors in a flexible interlocked metallic armor. See 320.100.
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### 320.6 Listing Requirements.
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Type AC cable and associated fittings shall be listed.
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## Part II. Installation
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### 320.10 Uses Permitted.
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Type AC cable shall be permitted as follows:
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1. For feeders and branch circuits in both exposed and concealed installations
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2. In cable trays
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3. In dry locations
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4. Embedded in plaster finish on brick or other masonry, except in damp or wet locations
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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
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Informational Note: The "Uses Permitted" is not an all-inclusive list.
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### 320.12 Uses Not Permitted.
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Type AC cable shall not be used as follows:
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1. Where subject to physical damage
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2. In damp or wet locations
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3. In air voids of masonry block or tile walls where such walls are exposed or subject to excessive moisture or dampness
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4. Where exposed to corrosive conditions
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5. Embedded in plaster finish on brick or other masonry in damp or wet locations
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### 320.15 Exposed Work.
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Exposed runs of cable, except as provided in 300.11(B), shall closely follow the surface of the building finish or of running boards.
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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
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subject to physical damage.
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### 320.17 Through or Parallel to Framing Members.
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Type AC cable shall be protected in accordance with 300.4(A), (C), and (D) where installed through or parallel to framing members.
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### 320.23 In Accessible Attics.
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Type AC cables in accessible attics or roof spaces shall be installed as specified in 320.23(A) and (B).
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#### 320.23(A) Cables Run Across the Top of Floor Joists.
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Where run across the top of floor joists, or within 2.1 m (7 ft) of the floor or floor joists across the face of rafters or studding, the cable
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shall be protected by guard strips that are at least as high as the cable. Where this space is not accessible by permanently instal led
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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.
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#### 320.23(B) Cable Installed Parallel to Framing Members.
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Where the cable is installed parallel to the sides of rafters, studs, or ceiling or floor joists, neither guard strips nor running boards shall
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be required, and the installation shall also comply with 300.4(D).
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### 320.24 Bending Radius.
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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
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not be less than five times the diameter of the Type AC cable.
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### 320.30 Securing and Supporting.
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#### 320.30(A) General.
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Type AC cable shall be supported and secured by staples; cable ties listed and identified for securement and support; straps, hangers,
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or similar fittings; or other approved means designed and installed so as not to damage the cable.
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#### 320.30(B) Securing.
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Unless otherwise permitted, Type AC cable shall be secured within 300 mm (12 in.) of every outlet box, junction box, cabinet, or fitting
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and at intervals not exceeding 1.4 m (41⁄ 2 ft).
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#### 320.30(C) Supporting.
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Unless otherwise permitted, Type AC cable shall be supported at intervals not exceeding 1.4 m (41⁄ 2 ft).
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Horizontal runs of Type AC cable installed in wooden or metal framing members or similar supporting means shall be considered
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supported and secured where such support does not exceed 1.4 m (41⁄ 2 ft) intervals.
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#### 320.30(D) Unsupported Cables.
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Type AC cable shall be permitted to be unsupported and unsecured where the cable complies with any of the following:
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1. Is fished between access points through concealed spaces in finished buildings or structures and supporting is impracticable
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2. Is not more than 600 mm (2 ft) in length at terminals where flexibility is necessary
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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
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electrical equipment and the cable and point of connection are within an accessible ceiling
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For the purposes of this section, Type AC cable fittings shall be permitted as a means of cable support.
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### 320.40 Boxes and Fittings.
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At all points where the armor of AC cable terminates, a fitting shall be provided to protect wires from abrasion, unless the design of the
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outlet boxes or fittings is such as to afford equivalent protection, and, in addition, an insulating bushing or its equivalent protection shall
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be provided between the conductors and the armor. The connector or clamp by which the Type AC cable is fastened to boxes or
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cabinets shall be of such design that the insulating bushing or its equivalent will be visible for inspection. Where change is made from
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Type AC cable to other cable or raceway wiring methods, a box, fitting, or conduit body shall be installed at junction points as required
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in 300.15.
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### 320.80 Ampacity.
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The ampacity shall be determined in accordance with 310.14.
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#### 320.80(A) Thermal Insulation.
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Armored cable installed in thermal insulation shall have conductors rated at 90°C (194°F). The ampacity of cable installed in these
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applications shall not exceed that of a 60°C (140°F) rated conductor. The 90°C (194°F) rating shall be permitted to be used for
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ampacity adjustment and correction calculations; however, the ampacity shall not exceed that of a 60°C (140°F) rated conductor.
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Where more than two Type AC cables containing two or more current-carrying conductors in each cable are installed in contact with
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thermal insulation, caulk, or sealing foam without maintaining spacing between cables, the ampacity of each conductor shall be
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adjusted in accordance with Table 310.15(C)(1).
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#### 320.80(B) Cable Tray.
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The ampacity of Type AC cable installed in cable tray shall be determined in accordance with 392.80(A).
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## Part III. Construction Specifications
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### 320.100 Construction.
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Type AC cable shall have an armor of flexible metal tape and shall have an internal bonding strip of copper or aluminum in intimate
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contact with the armor for its entire length.
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### 320.104 Conductors.
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Insulated conductors shall be of a type listed in Table 310.4(A) or those identified for use in this cable. In addition, the conductors shall
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have an overall moisture-resistant and fire-retardant fibrous covering. For Type ACT, a moisture-resistant fibrous covering shall be
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required only on the individual conductors.
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### 320.108 Equipment Grounding Conductor.
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Type AC cable shall provide an adequate path for fault current as required by 250.4(A)(5) or (B)(4) to act as an equipment grounding
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conductor.
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### 320.120 Marking.
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The cable shall be marked in accordance with 310.8, except that Type AC shall have ready identification of the manufacturer by
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distinctive external markings on the cable armor throughout its entire length.
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