SURFACE METAL RACEWAYS AND

SURFACE NONMETALLIC RACEWAYS A. Surface Metal Raceways 352-1. Use. The use of surface metal raceways shall be permitted in dry locations. They shall not be used (1) where subject to severe physical damage unless otherwise approved; (2) where the voltage is 300 volts or more between conductors unless the metal has a thickness of not less than .040 inch (1.02 mm); (3) where subject to corrosive vapors; (4) in hoistways; (5) in any hazardous (classified) location except Class I, Division 2 locations as permitted in the exception to Section 501-4(b); nor (6) concealed except as follows: Exception No. 1: Surface metal raceways shall be permitted for underplaster extensions where identified for such use. Exception No. 2: As permitted in Section 645-5(d)(2). (FPN): See definition of "Exposed - (As applied to wiring methods)" in Article 100. 352-2. Other Articles. Surface metal raceways shall comply with the applicable provisions of Article 300. 352-3. Size of Conductors. No conductor larger than that for which the raceway is designed shall be installed in surface metal raceway. 352-4. Number of Conductors in Raceways. The number of conductors installed in any raceway shall be no greater than the number for which the raceway is designed. The derating factors of Article 310, Note 8 (a) of Notes to Ampacity Tables of 0 to 2000 Volts shall not apply to conductors installed in surface metal raceways where all of the following conditions are met: (1) the crosssectional area of the raceway exceeds 4 square inches (2580 sq mm); (2) the current-carrying conductors do not exceed thirty in number; (3) the sum of the cross-sectional areas of all contained conductors does not exceed 20 percent of the interior cross-sectional area of the surface metal raceway. (FPN): For conductor cross-sectional area, see Tables 5, 5A, 6, and 8 and the applicable Notes to Tables at the beginning of Chapter 9. 352-5. Extension Through Walls and Floors. It shall be permissible to extend unbroken lengths of surface metal raceways through dry walls, dry partitions, and dry floors.