SECTION 918 – ELECTRICAL MATERIALS
918.01 Conduit and Fittings
Ensure that exposed conduit and fittings on sign structures are aluminum conforming to UL standards for rigid metallic conduit. Use fittings and accessories for aluminum conduit that are made of aluminum or stainless steel. Ensure that conduit and fittings used as a raceway for the installation of wires and cables conform to the following:
1.Rigid Nonmetallic Conduit. For rigid nonmetallic conduit, use PVC conduit made from virgin polyvinyl resins conforming to ASTM D 1784, Class 12454 -B. Ensure that the conduit exceeds all the property requirements including impact strength, chemical resistance, and flammability as listed in UL 651 and NEMA TC 2. Use rigid nonmetallic conduit that is Type II, Schedule 40 suitable for direct burial under ground in grass and/or berm areas, and Schedule 80 under roadways. Use fittings that are made from high-impact PVC, are the socket type, and are joined to the conduit using PVC solvent cement. Ensure that fittings, including couplings, conform to NEMA TC 3. Us e solvent cement to join PVC conduit that is a heavy -bodied cement complying with ASTM D 2564 and apply with a natural bristle or nylon brush.
2.Rigid Metallic Conduit. For rigid metallic conduit and fittings, use steel that conforms to UL 6, UL 514B, and ANSI C80.1. Manufacture steel conduit from milled steel tubing with a wall thickness equivalent to Schedule 40 pipe. Hot-dip galvanize the conduit for the entire length, including the threads. Ensure that the minimum weight of galvanized coating is 1 ounce per square foot. Supply electro-galvanized couplings. Manufacture rigid metallic conduit sweep elbows to conform to UL 6. Fabricate aluminum conduit and fittings from a copper-free, corrosion-resistant aluminum alloy, conforming to ASTM B 429, Alloy 6061-T6.
3.Flexible Metallic Conduit. Use flexible metal conduit that consists of spirally wound steel core covered with a PVC jacket manufactured according to Federal Specification A -A-55810 for liquid -tight, flexible, metal conduit. Ensure that associated fittings are of like material and provide positive grounding and a liquid -tight seal. Ensure that flexible metal conduit for use on sign structures has an aluminum core with a neoprene jacket.
4.Flexible Nonmetallic Conduit. Use coil able HDPE conduit made from virgin HDPE resin as per the minimum standard of PE345440E according to ASTM D 3350. Ensure conduit is circular and of uniform cross sectional area and dimensions in accordance with ASTM F 2160. Ensure conduit is of continuous length containing no welds or joints coiled on a reel. Additionally, conduit’s inner and outer walls are to be smooth and the inner wall is to be lubricated with manufacturer’s recommended lubricant . Conduit colors are to be integrally extruded throughout the conduit in the manufacturing process. Ensure conduit is permanently marked with a laser ink imprinter or heat embossed white lettering showing the diameter, size, sequential length marks, owners name, ASTM, SDR, and/or Schedule rating. Additional markings of date -of-manufacture, time, and batch-of-resin are to be identified and referenced to certifications and quality control test results. Ensure manufacturer provides certification of the pr operties specified and mark/label the reels with purchase order, project name and/or other information for tracking and receiving. Applicable material standards are required based on the following applications:
a.Direct Burial. Use conduit material with a rating of Schedule 80 conforming to ASTM F 2160, NEMA TC-7 EPEC-80 and certified for its intended use.
b.Innerduct. Use conduit material with a rating of Schedule 40 conforming to ASTM F 2160, NEMA TC-7 EPEC-40. ITS conduits used for the installation of Fiber Optic Cable including tracer wire, are to be extruded integrally colored orange to indicate its use for Communications. ITS conduits designated for electrical use are to be extruded integrally colored red to indicate its use for Electrical wiring. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
918.02 Cable and Wire
The manufacturer shall provide to the RE and the Contractor all splicing and terminating information necessary for proper installation of the cables and wires. Ensure that conductors are made of stranded copper and conform to the standard rule s of the American Institute of Electrical Engineers and of the National Board of Fire Underwriters. Do not use conductors that are smaller than No. 14 AWG or Brown and Sharp Gage. Ensure that conductors are soft annealed copper wire according to ASTM B 3, Class B for tin -coated conductors or are bare copper conductors according to ASTM B 8, Class B. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
918.02.01 Loop Detector Lead
Use only one type of loop detector lead on the Project.
918.02.02 Loop Wire
Ensure that the loop wire is thermoplastic single conductor wire with a 1/4 inch PVC tube or 1/4 inch, HDPE tube extruded over the loop detector wire, is manufactured in conformance with ICEA Publication No. S -61-402/NEMA Publication No. WC5, and conforms to the following:
1.For the conductor, use No. 14 AWG soft -drawn copper wire with 19 wire (Class C) stranding or 7 wire (Class B) stranding conforming to ASTM B 3 and ASTM B 8.
2.Use insulation that conforms to UL Type THHN/THWN and is rated for 600 volts.
3.Use extruded PVC tubing that is UL listed FR -1 rated at 221 °F, with a minimum wall thickness of 30 mils. Ensure that the tubing is chemical resistant and oil resistant with a moisture absorption of less than 1 percent. Use HDPE tubing that is UL listed with a minimum wall thickness of 30 mils.
918.02.03 Multiple Lighting and Service Wire
Use wire conforming to current ICEA -NEMA Standards Publi cation for Cross -linked-thermosetting-polyethylene- insulated Wire and Cable for the Tran smission and Distribution of Electrical Energy, ICEA Publication No. S-66-524/NEMA Publication No. WC 7 and UL Type RHW-USE. Ensure that the insulation is a heat -resistant, moisture-resistant submarine compound conforming to ICEA Publication No. S-66-524/NEMA Publication No. WC 7, except for the thickness of insulation. For all conductors, use insulation that is required for 600 volt rated circuit voltage according to Table 3-1 for cross-linked-thermosetting-polyethylene-insulated power cables, Column A of ICEA Publication No. S-66-524/NEMA Publication No. WC 7.
918.02.04 Traffic Signal Cable
Use only one type of traffic signal cable on the Project.
918.03 Bonding and Grounding Materials
For rigid metallic conduit with a diameter of 1 inch or more, use bushings that are hot-dip galvanized or electro-galvanized malleable iron, with a bakelite, nylon, or some other type of heat-resistant plastic molded and locked into the bushing. Use an aluminum, bronze, copper, or other corrosion-resistant metal lug. Ensure that the set screws, lug mounting, and binding screws are stainless steel. The Contractor may use threadless bushings at specific locations where the conduit is not threaded. Fabricate insulating bushings for rigid metallic conduit with a diameter of less than 1 inch of molded high-impact thermoset plastic with a high dielectric and mechanical strength. Bond the conduit with bonding lock nuts. Do not use bushings made of materials that support combustion. Use ground wire that is bare or insulated with a conductor that is 7 strand, soft-drawn copper conforming to ASTM B 8, Class B. Ensure that bare conductors are tinned. For insulated conductors, cover the conductor with an insulation that meets or exceeds the requirements of UL Type THW. Use ground rods that are 5/8 inch in diameter and 12 feet long, composed of a steel core with copper covering. Thoroughly weld the 2 metals so that an interlocking crystalline union is secur ed between the 2 metals. Ensure that the minimum thickness of the copper on the cylindrical portion of the rod averages at least 0.010 inch. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
918.04 Cable Connectors
Use cable connectors that are fused for on line wires and nonfused on neutral wires. Ensure that the connec tors are a waterproof inline type connector and are composed of a line side and a load side housing, each made of water -resistant synthetic rubber. In each housing, include a section to form a watertight seal around the cable, an interior arrangement to receive and retain the copper fuse contacts, and a watertight seal section at the point of disconnection. Use contacts that are spring loaded, designed for a maximum current of 30 amperes at 600 volts and have a 90 percent minimum conductivity. Ensure that the contacts are suitable for gripping a cartridge -type midget fuse. Ensure that the fuse is 13/32 inch in diameter and 1 1/2 inches in length and is rated at 5 amperes and that the contacts are fully annealed and compressed onto the cable. Determine the size of each housing based on the cable diameter. Permanently mark each side of the housing as either load side or line side. Submit manufacturer’s certification for all materials, components, and assemblies as specified in 106.07.
918.05 Resin Splicing Kits
A.Traffic Signals. Ensure that resin splicing kits are of a type having a soft plastic sealing packet and meet or exceed the conductor’s insulation voltage rating.
B.Highway Lighting and ITS. Ensure that resin splicing kits are of a type having a rigid molded plastic casing that is capable of being split laterally to allow insertion of the conductors. Ensure that the resin splicing kits meet or exceed the conductor’s insulation voltage rating and are suitable for use with the insulation material.
918.06 Electrical Tape
A.Friction Tape. Use friction tape that is the self-sticking, rubber-impregnated, woven cotton fabric type.
B.Insulating Tape. Use insulating tape that is self -bonding and designed for use with cross -linked polyethylene or rubber-insulated wire and cable and that provides a permanent electrical and watertight seal.
C.Jacket Tape. Use jacket tape that is a conformable vinyl, plastic electrical tape, is flame retardant, water resistant, and cold weather pliable. Ensure that the tape is heavy-duty with a minimum tensile strength of 20 pounds per inch, a minimum adhesion of 20 ounces per inch, and a minimum thickness of 8.5 mils.
918.07 Cable Racks
Use cable racks that are molded polycarbonate and have a dielectric strength of less than 2 microamps at 100,000 volts. Ensure that the polycarbonate used in the construction of the rack is fire retardant with an SE -1 rating. Use a cable rack that is 3 inches wide and 3 feet long in ground-installed junction boxes or that is 3 inches wide and 1 foot long in structures. Ensure that the cable rack contains 3 saddle arms with a capacity of 2 inches. As an alternative, the Contractor may use steel cable racks that consist of a steel channel, welded steel supports, a clip, and porcelain insulators for each support. Hot -dip galvanize all steel components. Use a cab le rack that is approximately 2 feet long with 3 supports in ground installed boxes an d 7 inches long with 1 support in junction boxes located on structures. Space support holes on the channel approximately 1 1/2 inches on center. Ensure that the cable supports are designed with an interlocking feature at the rear of the support to prevent tilting and that the installed cable supports extend approximately 4 inches from the rack. Construct the porcelain insulator required on each support with a hook bottom groove to prevent slipping. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
918.08 Cast Boxes and Fittings
Use cast boxes with suitable covers of lik e material held in place with stainless steel fasteners and sealed with a weatherproof neoprene gasket. Provide mounting lugs with cast boxes. Ensure that all mounting hardware is stainless steel. For cast iron boxes, conform to the requirements specified in 909.03. Hot-dip galvanize cast iron boxes and covers. Use aluminum boxes and covers that are either sand cast conforming to ASTM B 26, Alloy 356.0 -F or 356.0-T6, or die cast conforming to ASTM B 108, Alloy 356.0-T6. Use junction boxes for underdeck lighting that are cast iron of approved design, suited and adapted to the specific location and the number of conduit, nipples, and other required details. Use flush -type boxes for installation in a structure and surface-mounted-type boxes in all surface applications. Ensure that the cover has a neoprene gasket and is secured with stainless steel screws. If required, equip the box with busses to provide at least 5 full threads or a UL-approved watertight rigid conduit hub at each entry point of the conduit. Use cast aluminum for pull boxes and pull fittings exposed on sign structures. Use boxes that are of approved design, suited and adapted to the specific location and the number and arrangement of conduit, and other details for the installation. Ensure that boxes have external lugs for mounting and internal mounting buttons for mounting equipment. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
918.09 Cabinets
For cabinets, use aluminum alloy conforming to ASTM B 209, Alloy 6061-T6. Label the door of all meter and control equipment cabinets, other than traffic signal cabinets, with a permanent reflective metallic sign indicating the voltage and the word DANGER. Apply the sign on a 0.040 inch minimum thickness aluminum alloy sheet. Use lettering that is approximately 1 1/2 inches high and is red on a white background. Install the sign with 4 stainless steel vandal proof screws. Seal a print of the system field w iring in plastic and attach it to the inside of the door of each meter cabinet, control equipment, and controller cabinet. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
918.10 Panel Boards and Circuit Breakers
A.Traffic Signals. Use panel boards that are single-phase, 3 wire, 120/240 volt, with 70 ampere main-rated busses, conforming to Federal Specification W -P-115C, Type 1, Class 2. Use circuit breakers that are UL listed, comply with NEMA Standards, and conform to Federal Specification W-C-375C, Class 10A. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
B.Highway and Sign Lighting and ITS Device. Use panel boards and circuit breakers conforming to the following:
1.120/240-Volt. For 120/240 volt installations use panel boards that are single-phase, 3 wire with 100 ampere main-rated busses, conforming to Federal Specification W-P-115C, Type 1, Class 1. Use circuit breakers that are UL listed, comply with NEMA Standards, and to Federal Specification W -C-375B for Class 10A or Class 10B.
2.240/480-Volt. For 240/480 volt installations use panel boards that are single-phase, 3-wire, have main busses, rated as designated, and conform to Federal Specification W-P-115C, Type 1, Class 1. Use circuit breakers that are UL listed, comply with NEMA Standards, and conform to Federal Specification W-C-375B for Class 13B.
3.480-Volt. For 480 volt installations, use panel boards that are the size and type indicated and conform to Federal Specification W-P-115C, Type 1, Class 1. Use circuit breakers that are UL listed and comply with NEMA Standards. Ensure that the circuit breakers are manually operated, molded -case units conforming to Federal Specification W-C-375B for Class 13B. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
918.11 Photoelectric Controls
Use photoelectric controls that are rated for the control or lighting circuit voltage indicated. Provide mounting hardware to allow the u nit to be installed in whatever type of location is shown. Ensure that the mounting conforms to the EEI-NEMA Standards for physical and electrical interchangeability of light sensitive control devices. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
918.12 Pedestals, Poles, Transformer Bases, and Mast Bracket Arms
Fabricate pedestals, poles, transformer bases, and mast brac ket arms for traffic signal, highway lighting, and camera standards with materials according to the appropriate ASTM standard and the AASHTO Sta ndard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals. Weld and fabricate steel members according to AWS D1.1, Structural Welding code. For aluminum members, weld and fabricate according to ANSI/AWS D1.2 Structural Welding Code - Aluminum. Ensure that welding is performed by welders who are qualified according to ANSI/AWS D1.1 or ANSI/AWS D1.2, as appropriate. Submit copies of the welder qualifications upon request. Perform at least the minimum specified number of quality control inspections according to the applicable ANSI/AASHTO/AWS specification and any other tests and inspections necessary to control the quality of the work. Ensure that aluminum poles, lighting, bracket arms, and traffic signal mast arms have a rotary, sand-polish finish giving a nonreflecting outer surface. Ensure that the external surfaces of transformer bases and shoe bases have a satin-type finish. Hot-dip galvanize steel poles and steel traffic signal arms according to ASTM A 123. If wire or cable passes through a hole or runs along a surface at any point, through or on the complete assembly, ensure that the holes and surfaces are deburred and void of any sharp edges or protuberances that may damage the wire or cable. Install rubber grommets in the entrance hole to the shaft and mast arms where mid-mounted traffic signals are installed. When installing aluminum traffic signal standards, use stainless steel hardware, bolts, nuts, and washers conforming to
908.04 For steel traffic signal standards, use galvanized hardware, bolts, nuts, and washers conforming to 908.01.
The manufacturer shall test standards and mast bracke t arms to ensure compliance with specified material and strength requirements. Perform testing that also ensures that the items have been manufactured in conformance with the AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals. Ensure aluminum poles and mast bracket arms are factory wrapped to protect them during shipment. Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies. Submit 5 copies of the certification stipulating that the items conform to the strength and material requirements.
918.13 Tower Poles
Fabricate according to AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals.
918.14 Lamps
Submit a certificate of compliance, as specified in 106.07, for all materials, components, and assemblies.
1.Traffic Signal. Ensure that traffic signal lamps are 120/125 volts and clear. Use 135 watt lamps that are rated for 6,000 hours of life and 60 watt lamps that are rated for 8,000 hours of life. Ensure that the lamps meet or exceed the beam candlepower requirements of the ITE signal lamp standard and conform to with the following: Table 918.14-1 Requirements for Traffic Signal Lamps Indication Size Wattage Rated Initial Lumens Center Length 8 inch 60 595 2 7/16 inches 12 inch 135 1,750 3 inches Pedestrian 60 595 2 7/16 inches
2.Highway Lighting. Use high pressure sodium lamps that have electrical, physical, and photometric characteristics that conform to ANSI Standards. Ensure that the lamps are rated for 24,000 hours of average life (based on 10 hours per start) and are equipped with borosilicate glass, have a mogul base, have a universal burning position, and are of the following ANSI designation, initial lumen rating, and nominal lamp voltage:
Referenced in this section
Electrical Materials in other states
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Source: Standard Specifications for Road and Bridge Construction, 2019 (rev. 2022-12-21) Edition. Pages 545–549 of 651. View official source ↗