|
ARTICLE 300 — WTIZI lG MF.,THDDS
<br />(C) Cables Through Spaces. Behind Panels Designed to
<br />Allow Access. Cables or raceway -type wiring methods, in-
<br />stalled behind panels designed to allow access, shall be
<br />supported according to their applicable articles.
<br />(D) Cables and Raceways Parallel to Framing Vlein-
<br />bers and Furring Strips. In both exposed and concealed
<br />locations, where a cable- or raceway -type wiring method is
<br />installed parallel to framing members, such as joists,
<br />rafters, or studs, or is installed parallel to furring strips, the
<br />cable or raceway shall be installed and supported so that the
<br />nearest outside surface of the cable or raceway is not less
<br />than 32 mm (1 /a in.) from the nearest edge of the framing
<br />member or furring strips where nails or screws are likely to
<br />penetrate. Where this distance cannot be maintained, the
<br />cable or raceway shall be protected from penetration by
<br />nails or screws by a steel plate, sleeve, or equivalent at least
<br />1.6 MM ( in.) thick,
<br />Exception No, 1: Steel plates, sleeves, or the equivalent
<br />shall not be required to protect rigid metal conduit, inter-
<br />mediate metal conduit, rigid nonmetallic conduit, or elec-
<br />trical metallic tubing.
<br />Exception rVo, 2: For concealed work in finished build-
<br />ings, or finished parcels for prefabricated buildings where
<br />such supporting is impracticable, it shall be permissible to
<br />fish the cables between access points.
<br />Exception No. 3': A listed and marked steel plate less than
<br />1.6 nun ( in.) thick that provides equal or better protec-
<br />tion against mail or° screw penetration shall be permitted.
<br />(1) Cables; Raceways, or Boxes Installed in or Under
<br />Roof Decking. A cable, raceway, or box, installed in ex-
<br />posed or concealed locations under metal- corrugated sheet
<br />roof decking, shall be installed and supported so there is
<br />not less than 38 mm (1' /z in.) Measured from the lowest
<br />surface of the roof decking to, the top of the cable, raceway,
<br />or box. A cable, raceway, or box- shall not be installed in
<br />concealed locations in metal - con ugated, sheet `i decking–
<br />type roof.
<br />Informational Note: Roof decking material is often re-
<br />paired or replaced after the initial raceway or cabling and
<br />rooting installation and may be penetrated by the screws or
<br />other mechanical devices designed to provide "hold down"
<br />strength of the waterproof membrane or roof insulating
<br />material.
<br />Exception: Rigid metal conduit and intermediate metal
<br />conduit .shall not be required to comply with 300.4(E).
<br />(F) Cables and Raceways Installed in Shallow Grooves.
<br />Cable- or raceway type wiring methods installed in a
<br />groove, to be covered by wallboard, siding, paneling, car-
<br />peting, or similar finish, shall be protected by 1,6 mni
<br />( /t6 in.) thick steel plate, sleeve, or equivalent or by not
<br />300.,5
<br />less than 32 -mni (I 1 /4-in.) free space for the full length of
<br />the groove in which the cable or raceway is installed,
<br />Exception No. 1: Steel plates, sleeves, or the equivalent
<br />shall not be required to protect ri metal conduit, inter_
<br />mediate metal conduit, rigid nonmetallic conduit, or elec-
<br />trical metallic tubing.
<br />Exception aVo. 2: A listed and marked steel plate less than
<br />1.6 non (alas in.) thick that provides equal or better protec-
<br />tion against mail or screw penetration shall be permitted.
<br />(G) Insulated Fittings. Where raceways contain 4 AWG
<br />or larger insulated circuit conductors, and these conductors .
<br />enter a cabinet, a box, an enclosure, or a raceway, the con-
<br />ductors shall be protected by an identified fitting providing
<br />a smoothly rounded insulating surface, unless the conduc-
<br />tors are separated from the fitting or raceway by identified
<br />insulating material that is securely fastened in place.
<br />Exception: Where threaded )rubs or bosses that are an
<br />integral part of a cabinet, box, enclosure, or raceivay pro -
<br />vide a smoothly rounded or flared entry for conductors.
<br />Conduit bushings constructed wholly of insulating ma-
<br />terial shall not be used to secure a fitting or raceway. The
<br />insulating fitting or insulating material shall have a tem-
<br />perature rating not less than the insulation temperature rat-
<br />ing of the installed conductors.
<br />(H) Structural Joints. A listed expansion/deflection fitting
<br />or other approved means shall be used where a raceway
<br />crosses a structural joint intended for expansion, contrac-
<br />tion or deflection, used in buildings, bridges, parking ga-
<br />rages, or other structures
<br />300.5 Underground Installations.
<br />(A) Minimum Cover Requirements. Direct- buried cable
<br />or conduit or other raceways shall be installed to meet the
<br />minimum cover requirements of Table 300.5.
<br />(B) Wet Locations. The interior of enclosures or raceways
<br />installed underground shall be considered to be a wet location.
<br />Insulated conductors and cables installed in these enclosures
<br />or raceways in underground installations shall be listed for use
<br />in wet locations and shall comply with 310.10(0). Any con-
<br />nections or splices in an underground installation shall be ap-
<br />proved for wet locations.
<br />(C) Underground Cables Under Buildings. Underground
<br />cable installed under a building shall be in a raceway.
<br />Exception aVo. 1: Type All usable shall be permitted under-
<br />a building without installation in a raceivay i0iew embed-
<br />ded in concrete, ,fall, or other masonry in accorxdnracc With
<br />332.10(6) or in underground nuns Where "suitably protected
<br />against physical damage and corrosive conditions in accor-
<br />dance with 3. 2.1 ®(11?):
<br />2011 Edition NATIONAL ELECTRICAL CODE 70-137
<br />
|