923.1 General Description
This section includes the requirements for metallic, nonmetallic, and flexible electrical conduit.
923.1.01 Related References
A. Standard Specifications General Provisions 101 through 150. B. Referenced Documents ANSI C-80.1, American National Standard for Electrical Rigid Steel Conduit (ERSC) ASTM A 90, Standard Test Method for Weight [Mass] of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings ASTM D1784 Standard Classification System and Basis for Specification for Rigid Poly(Vinyl Chloride) (PVC) Compounds and Chlorinated Poly(Vinyl Chloride) (CPVC) Compounds Federal Specification WW-C-540c, CONDUIT, METAL RIGID, (ELECTRICAL ALUMINUM) Federal Specification W-C-1094a, CONDUIT AND CONDUIT FITTINGS PLASTIC, RIGID National Electrical Manufacturer’s Association (NEMA) standards: NEMA FB 1 Fittings, Cast Metal Boxes, and Conduit Bodies for Conduit and Cable Assemblies NEMA TC-2, Electrical Polyvinyl Chloride (PVC) Conduit NFPA 70, National Electrical Code (latest edition) Underwriter’s Laboratories (UL) Standards: UL 6, Standard for Electrical Rigid Metal Conduit - Steel UL 6A, Standard for Electrical Rigid Metal Conduit - Aluminum, Red Brass, and Stainless Steel UL 44, Standard for Thermoset-Insulated Wires and Cables UL 50, Standard for Enclosures for Electrical Equipment UL 50E, Standard for Elastomers for Electrical Equipment Enclosure Requirements UL 83, Standard for Thermoplastic-Insulated Wires and Cables UL 94, Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances UL 486A-486B, Standard for Wire Connectors UL 514B – Conduit, Tubing and Cable Fittings UL 651, Standard for Schedule 40, 80, Type EB and A Rigid PVC Conduit and Fittings UL 746A, Standard for Polymeric Materials - Short Term Property Evaluations UL 746B, Standard for Polymeric Materials - Long Term Property Evaluations UL 969, Standard for Marking and Labeling Systems UL- 1660 Liquid-Tight Flexible Nonmetallic Conduit (Type B). UL 1684, Standard for Safety for Reinforced Thermosetting Resin Conduit (RTRC) and Fittings National Electrical Manufacturers Association (NEMA) Standards: NEMA TC-2, Electrical Polyvinyl Chloride (PVC) Tubing and Conduit NEMA TC-3, Polyvinyl Chloride (PVC) Fittings for Use with Rigid PVC Conduit and Tubing NEMA TC-6&8, Polyvinyl Chloride (PVC) Plastic Utilities for Underground Installations NEMA TC-7, Smooth Wall Coilable Electrical Polyethylene Conduit NEMA TC-9, Fittings for Polyvinyl Chloride (PVC) Plastic Utilities Duct for Underground Installations NEMA TC-13, Electrical Nonmetallic Tubing (ENT) NEMA TC-14, Reinforced Thermosetting Resin Conduit and Fittings Series. Same as UL 1684.
923.2 Materials
923.2.01 Rigid Metallic Conduit
A. Requirements 1. General Requirements for all Rigid Metallic Conduit a. Use metallic conduit that meets the requirements of and is used according to the latest edition of the National Electrical Code Article 344. b. the type and material of conduit specified within the Contract. c. Ensure each section of conduit bears the listing mark by the Underwriter’s Laboratories, Inc. (UL) or a Nationally Recognized Testing Laboratory (NRTL). d. All RMC conduit must be listed to UL 6 or 6A. e. Ensure that rigid steel conduit, elbows, and couplings meet ANSI C-80.1. f. Use fittings of the same material as the conduit to avoid galvanic corrosion. g. Use fittings that are NRTL listed to the appropriate UL standards 2. Galvanized Rigid Steel Conduit a. Galvanized steel shall be used for all Rigid Metall Conduit installations, unless otherwise specified. b. Use conduit protected by a uniform metallic zinc coating on both the exterior and interior surfaces. c. Conduit and couplings must have a minimum zinc coating of 1.24 oz./ft.² (378 g/m²), total of both surfaces. d. Determine the weight of the zinc coating using either ASTM A 90, or, if the Engineer elects, a magnetic or electromagnetic thickness gage to measure the coating thickness. 3. Rigid Aluminum Conduit (Aluminum RMC) a. Ensure that rigid aluminum conduit, elbows, and couplings meet Federal Specification WW-C-540c. b. Aluminum RMC shall be provided with approved supplementary corrosion protection where encased in concrete or in direct contact with the earth. c. Install only as specified in the Contract. 4. Stainless Steel Conduit a. Stainless steel conduit, elbows, couplings, and fittings may be permitted to be installed in concrete, in direct contact with the earth, or in areas subject to severe corrosive influences where protected by corrosion protection approved for the condition. b. Install only as specified in the Contract. B. Fabrication General Provisions 101 through 150. C. Acceptance General Provisions 101 through 150. D. Materials Warranty General Provisions 101 through 150.
923.2.02 Rigid Nonmetallic Conduit
A. Requirements All Non-Metallic Conduit shall be Polyvinyl Chloride (Type PVC) Conduit. Ensure unplasticized PVC conduit meets the requirements of UL 651. 1. Type II Conduit (Schedule 40 PVC) a. Use Type II conduit for all direct buried conduit as well as all conduit encased or embedded in concrete. b. May be used as specified in Contract for exposed or concealed applications above ground c. All Type II shall be Schedule 40 (heavy wall), unplasticized PVC conduit that meets the requirements of Federal Specification W-C-1094a, unless otherwise specified. d. Must be rated for use with 90°C conductors. e. Must meet Federal Specification WC1094a and NEC Article 352. 2. Type III Conduit (HDPE) Use Type III conduit when specified within the Contract, which is HDPE. ASTM D3035-15, Standard Specification for Polyethylene (PE) Plastic Pipe (DR-PR) Based on Controlled Outside Diameter, ASTM International, West Conshohocken, PA, 2015, www.astm.org 3. Fiberglass Reinforced Epoxy (FRE) Conduit: Type RTRC a. Use FRE conduit and fittings that meet the requirements of NEMA Standard TC 14, NEC Article 355 applies. b. The Department shall approve all materials and design of bridge-attached conduit systems prior to any field installation. All bridge hanger assembly components that are in contact with the FRE conduit’s outer surface shall be manufactured of the same fiberglass reinforced epoxy material or shall employ low- friction roller bushings.
923.2.03 Directionally Bored Conduit
A. Requirements Conduits used for boring shall be either steel or HDPE, standard dimension ratio 11 (SDR-11) or better and shall meet the requirements of ASTM D3035-15. B. Fabrication General Provisions 101 through 150. C. Acceptance General Provisions 101 through 150. D. Materials Warranty General Provisions 101 through 150.
923.2.04 Flexible Conduit: Type LFMC (Liquid tight Flexible Nonmetallic Conduit)
A. Requirements 1. Use flexible liquid tight UV-resistant conduit that is compliant with UL 1660 (Type B). 2. Use conduit that meets the requirements of Article 350 of the National Electrical Code, including maximum lengths allowed. 3. This type should be used for electrical service to luminaires under bridge decks or in tunnels, or where vibration may be an issue. B. Fabrication General Provisions 101 through 150. C. Acceptance General Provisions 101 through 150. D. Materials Warranty General Provisions 101 through 150.
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