260519 Low Voltage - Copy.docx
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- 36C24826Q0188
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This document is a technical specification for low-voltage electrical power conductors and cables (Section 26 05 19). The specification provides detailed requirements for copper conductors, cable types, conductor color coding, splices, connectors, and terminations, covering electrical systems rated 600V and below. Key technical requirements include conductor sizes ranging from No. 12 AWG minimum, insulation types (THHN-THWN and XHHW-2), color coding standards for different voltage systems, and specific installation guidelines for various conductor types and environments.
The specification outlines comprehensive installation instructions, including conductor pulling techniques, splice and termination methods, identification requirements, and acceptance testing procedures. Notable execution requirements include limiting branch circuits to three per conduit, using appropriate pulling equipment to prevent cable damage, performing insulation resistance tests, and ensuring mechanical and electrical security of all connections. The document is structured to provide engineers and contractors with precise technical guidance for electrical conductor and cable installation in compliance with national electrical standards.
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11-01-22
SECTION 26 05 19
LOW-VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES
SPEC WRITER NOTE: Delete between //_____// if not applicable to project. Also delete any other item or paragraph not applicable to the section and renumber the paragraphs.
PART 1 ‑ GENERAL
1.1 DESCRIPTION
A. This section specifies the furnishing, installation, connection, and testing of the electrical conductors and cables for use in electrical systems rated 600 V and below, indicated as cable(s), conductor(s), wire, or wiring in this section.
1.2 RELATED WORK
| A. | Section 07 84 00, FIRESTOPPING: Sealing around penetrations to maintain the integrity of fire-resistant rated construction. |
| B. | Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS: Requirements that apply to all sections of Division 26. |
| C. | Section 26 05 26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS: Requirements for personnel safety and to provide a low impedance path for possible ground fault currents. |
| D. | Section 26 05 33, RACEWAY AND BOXES FOR ELECTRICAL SYSTEMS: Conduits for conductors and cables. |
| E. | Section 26 05 41, UNDERGROUND ELECTRICAL CONSTRUCTION: Installation of conductors and cables in manholes and ducts. |
1.3 qualITY ASSURANCE A. Quality Assurance shall be in accordance with Paragraph, QUALIFICATIONS (PRODUCTS AND SERVICES) in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS.
1.4 SUBMITTALS
| A. | Submit in accordance with Paragraph, SUBMITTALS in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS, and the following requirements: |
| 1. | Shop Drawings: |
| a. | Submit sufficient information to demonstrate compliance with drawings and specifications. |
| b. | Submit the following data for approval: |
| 1) | Electrical ratings and insulation type for each conductor and cable. |
| 2) | Splicing materials and pulling lubricant. |
| 2. | Certifications: Two weeks prior to final inspection, submit the following. |
| a. | Certification by the manufacturer that the conductors and cables conform to the requirements of the drawings and specifications. |
| b. | Certification by the Contractor that the conductors and cables have been properly installed, adjusted, and tested. |
1.5 APPLICABLE PUBLICATIONS
| A. | Publications listed below (including amendments, addenda, revisions, supplements and errata) form a part of this specification to the extent referenced. Publications are reference in the text by designation only. |
| B. | American Society of Testing Material (ASTM): |
| D2301-10 | Standard Specification for Vinyl Chloride Plastic Pressure-Sensitive Electrical Insulating Tape |
| D2304-18 | Test Method for Thermal Endurance of Rigid Electrical Insulating Materials |
| D3005-17 | Low-Temperature Resistant Vinyl Chloride Plastic Pressure-Sensitive Electrical Insulating Tape |
| C. | National Electrical Manufacturers Association (NEMA): |
| WC 70-21 | Power Cables Rated 2000 Volts or Less for the Distribution of Electrical Energy |
| D. | National Fire Protection Association (NFPA): |
| 70-23 | National Electrical Code (NEC) |
| E. | Underwriters Laboratories, Inc. (UL): |
| 44-18 | Thermoset-Insulated Wires and Cables |
| 83-17 | Thermoplastic-Insulated Wires and Cables |
| 467-13 | Grounding and Bonding Equipment |
| 486A-486B-18 | Wire Connectors |
| 486C-18 | Splicing Wire Connectors |
| 486D-15 | Sealed Wire Connector Systems |
| 486E-15 | Equipment Wiring Terminals for Use with Aluminum and/or Copper Conductors |
| 493-18 | Thermoplastic-Insulated Underground Feeder and Branch Circuit Cables |
| 514B-12 | Conduit, Tubing, and Cable Fittings |
PART 2 ‑ PRODUCTS
2.1 conductors and CABLES
| A. | Conductors and cables shall be in accordance with ASTM, NEMA, NFPA, UL, as specified herein, and as shown on the drawings. |
| B. | Conductors shall be copper. |
| C. | Single Conductor: |
| 1. | No. 12 AWG: Minimum size, except where smaller sizes are specified herein or shown on the drawings. |
| 2. | No. 8 AWG and larger: Stranded. |
| 3. | No. 10 AWG and smaller: Solid; except shall be stranded for final connection to motors, transformers, and vibrating equipment. |
| 4. | Insulation: THHN-THWN and XHHW-2. XHHW-2 shall be used for isolated power systems. |
SPEC WRITER NOTE: Delete the paragraph below if these cables types are not required. These cables types are used only for temporary installation of normal power.
| //D. | Direct Burial Cable: UF or USE cable.// |
| E. | Conductor Color Code: |
| 1. | No. 10 AWG and smaller: Solid color insulation or solid color coating. |
| 2. | No. 8 AWG and larger: Color-coded using one of the following methods: |
| a. | Solid color insulation or solid color coating. |
| b. | Stripes, bands, or hash marks of color specified. |
| c. | Color using 19 mm (0.75 inches) wide tape. |
| 4. | For modifications and additions to existing wiring systems, color coding shall conform to the existing wiring system. |
| 5. | Conductors shall be color-coded as follows: |
| 208/120 V | |
| Phase | |
| 480/277 V |
| Black |
| A |
| Brown |
| Red |
| B |
| Orange |
| Blue |
| C |
| Yellow |
| White |
| Neutral |
| Gray * |
* or white with colored (other than green) tracer.
| 6. | Lighting circuit “switch legs”, and 3-way and 4-way switch “traveling wires,” shall have color coding that is unique and distinct (e.g., pink and purple) from the color coding indicated above. The unique color codes shall be solid and in accordance with the NEC. Coordinate color coding in the field with the //Resident Engineer// //COR///. |
| 7. | Color code for isolated power system wiring shall be in accordance with the NEC. |
2.2 SPLICES
| A. | Splices shall be in accordance with NEC and UL. |
| B. | Above Ground Splices for No. 10 AWG and Smaller: |
| 1. | Solderless, screw‑on, reusable pressure cable type, with integral insulation, approved for copper and aluminum conductors. |
| 2. | The integral insulator shall have a skirt to completely cover the stripped conductors. |
| 3. | The number, size, and combination of conductors used with the connector, as listed on the manufacturer's packaging, shall be strictly followed. |
| C. | Above Ground Splices for No. 8 AWG to No. 4/0 AWG: |
| 1. | Compression, hex screw, or bolt clamp‑type of high conductivity and corrosion‑resistant material, listed for use with copper and aluminum conductors. |
| 2. | Insulate with materials approved for the particular use, location, voltage, and temperature. Insulation level shall be not less than the insulation level of the conductors being joined. |
| 3. | Splice and insulation shall be product of the same manufacturer. |
| 4. | All bolts, nuts, and washers used with splices shall be //zinc-plated//cadmium-plated// steel. |
| D. | Above Ground Splices for 250 kcmil and Larger: |
| 1. | Long barrel “butt-splice” or “sleeve” type compression connectors, with minimum of two compression indents per wire, listed for use with copper and aluminum conductors. |
| 2. | Insulate with materials approved for the particular use, location, voltage, and temperature. Insulation level shall be not less than the insulation level of the conductors being joined. |
| 3. | Splice and insulation shall be product of the same manufacturer. |
SPEC WRITER NOTE: Delete the paragraphs below if underground splices types are not required.
| //E. | Underground Splices for No. 10 AWG and Smaller: |
| 1. | Solderless, screw‑on, reusable pressure cable type, with integral insulation. Listed for wet locations, and approved for copper and aluminum conductors. |
| 2. | The integral insulator shall have a skirt to completely cover the stripped conductors. |
| 3. | The number, size, and combination of conductors used with the connector, as listed on the manufacturer's packaging, shall be strictly followed. |
| F. | Underground Splices for No. 8 AWG and Larger: |
| 1. | Mechanical type, of high conductivity and corrosion‑resistant material. Listed for wet locations, and approved for copper and aluminum conductors. |
| 2. | Insulate with materials approved for the particular use, location, voltage, and temperature. Insulation level shall be not less than the insulation level of the conductors being joined. |
| 3. | Splice and insulation shall be product of the same manufacturer.// |
| G. | Plastic electrical insulating tape: Per ASTM D2304, flame-retardant, cold and weather resistant. |
2.3 CONNECTORS and terminations
| A. | Mechanical type of high conductivity and corrosion‑resistant material, listed for use with copper and aluminum conductors. |
| B. | Long barrel compression type of high conductivity and corrosion‑resistant material, with minimum of two compression indents per wire, listed for use with copper and aluminum conductors. |
| C. | All bolts, nuts, and washers used to connect connections and terminations to bus bars or other termination points shall be //zinc-plated//cadmium-plated// steel. |
2.4 CONTROL WIRING
| A. | Unless otherwise specified elsewhere in these specifications, control wiring shall be as specified herein, except that the minimum size shall be not less than No. 14 AWG, or as required by the control wiring equipment manufacturer. |
| B. | Control wiring shall be sized such that the voltage drop under in-rush conditions does not adversely affect operation of the controls. |
2.5 WIRE LUBRICATING COMPOUND
| A. | Lubricating compound shall be suitable for the wire insulation and conduit, and shall not harden or become adhesive. |
| B. | Shall not be used on conductors for isolated power systems. |
PART 3 ‑ EXECUTION
3.1 GENERAl
| A. | Installation shall be in accordance with the NEC, as shown on the drawings, and manufacturer’s instructions. |
| B. | Install conductors in raceway systems. |
| C. | Splice conductors only in outlet boxes, junction boxes, pullboxes, manholes, or handholes. |
| D. | Conductors of different systems (e.g., 120 V and 277 V) shall not be installed in the same raceway. |
| E. | For conductors installed in vertical raceways, provide conductor support (also known as cable support), to counter gravity pull on conductor weight. Conductor support shall be split-wedge conductor support type. Prior to installing the conductor support plug, remove all pulling compound from conductors where they pass through the conductor support body. After installing the conductor support plug, tap the conductor support plug firmly in the conductor support body. |
| F. | In panelboards, cabinets, wireways, switches, enclosures, and equipment assemblies, neatly form, train, and tie the conductors with non-metallic “zip” ties. |
| G. | For connections to motors, transformers, and vibrating equipment, stranded conductors shall be used only from the last fixed point of connection to the motors, transformers, or vibrating equipment. |
| H. | Use expanding foam or non-hardening duct-seal to seal conduits entering a building, after installation of conductors. |
| I. | Conductor Pulling: |
| 1. | Provide installation equipment that will prevent the cutting or abrasion of insulation during pulling. Use lubricants approved for the cable. |
| 2. | Use nonmetallic pull ropes. |
| 3. | Attach pull ropes by means of either woven basket grips or pulling eyes attached directly to the conductors. |
| 4. | All conductors in a single conduit shall be pulled simultaneously. |
| 5. | Do not exceed manufacturer’s recommended maximum pulling tensions and sidewall pressure values. |
| J. | Number of conductors for branch circuits shall not exceed more than three branch circuits in any one conduit. |
| K. | When stripping stranded conductors, use a tool that does not damage the conductor or remove conductor strands. |
3.2 INSTALLATION IN MANHOLES
| A. | Train the conductors around the manhole walls, but do not bend to a radius less than six times the overall conductor diameter. |
| //B. | Fireproofing: |
| 1. | Install fireproofing on low-voltage conductors where the low-voltage conductors are installed in the same manholes with medium-voltage conductors. |
| 2. | Use fireproofing tape as specified in Section 26 05 13, MEDIUM-VOLTAGE CABLES, and apply the tape in a single layer, half-lapped, or as recommended by the manufacturer. Install the tape with the coated side towards the cable and extend it not less than 25 mm (1 inch) into each duct. |
| 3. | Secure the fireproofing tape in place by a random wrap of glass cloth tape.// |
3.3 SPLICE and termination INSTALLATION
| A. | Splices and terminations shall be mechanically and electrically secure, and tightened to manufacturer’s published torque values using a torque screwdriver or wrench. |
| B. | Where the Government determines that unsatisfactory splices or terminations have been installed, replace the splices or terminations at no additional cost to the Government. |
3.4 conductor identification A. When using colored tape to identify phase, neutral, and ground conductors larger than No. 8 AWG, apply tape in half-overlapping turns for a minimum of 75 mm (3 inches) from terminal points, and in junction boxes, pullboxes, and manholes. Apply the last two laps of tape with no tension to prevent possible unwinding. Where markings are covered by tape, apply tags to conductors, stating size and insulation type.
3.5 FEEDER conductor IDENTIFICATION
A. In each interior pullbox and each underground manhole and handhole, install brass tags on all feeder conductors to clearly designate their circuit identification and voltage. The tags shall be the embossed type, 40 mm (1-1/2 inches) in diameter and 40 mils thick. Attach tags with plastic ties.
3.6 existIng conductors A. Unless specifically indicated on the plans, existing conductors shall not be reused.
3.7 CONTROL WIRING INSTALLATION
A. Unless otherwise specified in other sections, install control wiring and connect to equipment to perform the required functions as specified or as shown on the drawings.
SPEC WRITER NOTE: Each separate system shall have a dedicated power supply circuit.
B. Install a separate power supply circuit for each system, except where otherwise shown on the drawings.
3.8 CONTROL wiring IDENTIFICATION
| A. | Install a permanent wire marker on each wire at each termination. |
| B. | Identifying numbers and letters on the wire markers shall correspond to those on the wiring diagrams used for installing the systems. |
| C. | Wire markers shall retain their markings after cleaning. |
| D. | In each manhole and handhole, install embossed brass tags to identify the system served and function. |
SPEC WRITER NOTE: Delete the paragraph below if these cables types are not required. These cables types are used only for temporary installation of normal power.
//3.9 DIRECT BURIAL CABLE INSTALLATION
| A. | Tops of the cables: |
| 1. | Below the finished grade: Minimum 600 mm (24 inches) unless greater depth is shown. |
| 2. | Below road and other pavement surfaces: In conduit as specified, minimum 760 mm (30 inches) unless greater depth is shown. |
| 3. | Do not install cables under railroad tracks. |
| B. | Under road and paved surfaces: Install cables in concrete-encased galvanized steel rigid conduits. Size as shown on plans, but not less than 50 mm (2 inches) trade size with bushings at each end of each conduit run. Provide size/quantity of conduits required to accommodate cables plus one spare. |
| C. | Work with extreme care near existing ducts, conduits, cables, and other utilities to prevent any damage. |
| D. | Excavation and backfill is specified in Section 31 20 00, EARTH MOVING. In addition: |
| 1. | Place 75 mm (3 inches) bedding sand in the trenches before installing the cables. |
| 2. | Place 75 mm (3 inches) shading sand over the installed cables. |
| 3. | Install continuous horizontal 25 mm by 200 mm (1 inch x 8 inches) preservative-impregnated wood planking 75 mm (3 inches) above the cables before backfilling. |
| E. | Provide horizontal slack in the cables for contraction during cold weather. |
| F. | Install the cables in continuous lengths. Splices within cable runs shall not be accepted. |
| G. | Connections and terminations shall be listed submersible-type designed for the cables being installed. |
| H. | Warning tape shall be continuously placed 300 mm (12 inches) above the buried cables.// |
3.10 Acceptance Checks and Tests
| A. | Perform in accordance with the manufacturer's recommendations. In addition, include the following: |
| 1. | Visual Inspection and Tests: Inspect physical condition. |
| 2. | Electrical tests: |
| a. | After installation but before connection to utilization devices, such as fixtures, motors, or appliances, test conductors phase-to-phase and phase-to-ground resistance with an insulation resistance tester. Existing conductors to be reused shall also be tested. |
| b. | Applied voltage shall be 500 V DC for 300 V rated cable, and 1000 V DC for 600 V rated cable. Apply test for one minute or until reading is constant for 15 seconds, whichever is longer. Minimum insulation resistance values shall not be less than 25 megohms for 300 V rated cable and 100 megohms for 600 V rated cable. |
| c. | Perform phase rotation test on all three-phase circuits. |
---END---
26 05 19 - 2
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