Lesser depths shall be permitted where cables and conductors rise for terminations or splices or where access is otherwise required.Ģ. Raceways Under Buildings or Exterior Concrete Slabs, 100 mm (4 in.) Minimum Thickness dĬables in Airport Runways or Adjacent Areas Where Trespass Is ProhibitedĪreas Subject to Vehicular Traffic, Such as Thoroughfares and Commercial Parking Areas Rigid Metal Conduit and Intermediate Metal Conduit General Conditions (not otherwise specified) Table 300.50 Minimum Cover a Requirements Circuit Voltage The raceways shall be covered by a minimum of 50 mm (2 in.) of concrete extending down to rock. Where solid rock prevents compliance with the cover depths specified in this table, the wiring shall be installed in a metal raceway, or a nonmetallic raceway permitted for direct burial. Where one of the wiring method types listed in Columns 1 through 3 is used for one of the circuit types in Columns 4 and 5, the shallowest depth of burial shall be permitted.ĥ. Lesser depths shall be permitted where cables and conductors rise for terminations or splices or where access is otherwise required.Ĥ. Raceways approved for burial only where concrete encased shall require concrete envelope not less than 50 mm (2 in.) thick.ģ. Cover is defined as the shortest distance in mm (in.) measured between a point on the top surface of any direct-buried conductor, cable, conduit, or other raceway and the top surface of finished grade, concrete, or similar cover.Ģ. In or under airport runways, including adjacent areas where trespassing prohibitedĪA lesser depth shall be permitted where specified in the installation instructions of a listed low-voltage lighting system.īA depth of 150 mm (6 in.) shall be permitted for pool, spa, and fountain lighting, installed in a nonmetallic raceway, limited to not more than 30 volts where part of a listed low-voltage lighting system.ġ. One- and two-family dwelling driveways and outdoor parking areas, and used only for dwelling-related purposes Under streets, highways, roads, alleys, driveways, and parking lots Under minimum of 102 mm (4 in.) thick concrete exterior slab with no vehicular traffic and the slab extending not less than 152 mm (6 in.) beyond the underground installation (in raceway or Type MC or Type MI cable identified for direct burial) In trench below 50 mm (2 in.) thick concrete or equivalent Table 300.5 Minimum Cover Requirements, 0 to 1000 Volts, Nominal, Burial in Millimeters (Inches) Location of Wiring Method or CircuitĬolumn 1 Direct Burial Cables or ConductorsĬolumn 2 Rigid Metal Conduit or Intermediate Metal ConduitĬolumn 3 Nonmetallic Raceways Listed for Direct Burial Without Concrete Encasement or Other Approved RacewaysĬolumn 4 Residential Branch Circuits Rated 120 Volts or Less with GFCI Protection and Maximum Overcurrent Protection of 20 AmperesĬolumn 5 Circuits for Control of Irrigation and Landscape Lighting Limited to Not More Than 30 Volts and Installed with Type UF or in Other Identified Cable or Raceway
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