VA 26 05 41-2010 UNDERGROUND ELECTRICAL CONSTRUCTION.pdf

1、09-10 26 05 41 - 1 SECTION 26 05 41 UNDERGROUND ELECTRICAL CONSTRUCTION SPEC WRITER NOTE: Delete /_/ if not applicable to project. Also delete any other item or paragraph not applicable in the section and renumber the paragraphs. Insert additional provisions as required for this project. PART 1 - GE

2、NERAL 1.1 DESCRIPTION A. This section specifies the furnishing, installation, and connection of precast manholes and pullboxes with ducts to form a complete underground raceway system. B. “Duct” and “conduit,” and “rigid metal conduit” and “rigid steel conduit” are used interchangeably in this speci

3、fication. 1.2 RELATED WORK A. Section 07 92 00, JOINT SEALANTS: Sealing of conduit penetrations. B. Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS: General electrical requirements and items that are common to more than one section of Division 26. C. Section 26 05 26, GROUNDING AND BONDI

4、NG 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, fittings and boxes for raceway systems. E. /Section 31 20 00, EARTH MOVING/ /Section 31 20 11,

5、 EARTH MOVING (SHORT FORM)/: Trenching, backfill and compaction. 1.3 QUALITY ASSURANCE A. Refer to Paragraph, QUALIFICATIONS, in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS. B. Coordinate layout and installation of ducts, manholes, pullboxes, and pull-boxes with final arrangement of

6、other utilities, site grading, and surface features, as determined in the field. 1.4 SUBMITTALS A. Submit in accordance with Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS. B. Shop Drawings: 1. Clearly present sufficient information to determine compliance with drawings and specificatio

7、ns. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 05 41 - 2 2. Include manholes, pullboxes, duct materials, and hardware. Submit plan and elevation drawings, showing openings, pulling irons, cable supports, cover, ladder, sump, and other a

8、ccessories and details. 3. Proposed deviations from details on the drawings shall be clearly marked on the submittals. If it is necessary to locate manholes or pullboxes at locations other than shown on the drawings, show the proposed locations accurately on scaled site drawings, and submit four cop

9、ies to the /Resident Engineer/ /COTR/ for approval prior to construction. C. Certifications: Two weeks prior to the final inspection, submit four copies of the following certifications to the /Resident Engineer/ /COTR/: 1. Certification by the manufacturer that the materials conform to the requireme

10、nts of the drawings and specifications. 2. Certification by the contractor that the materials have been properly installed, connected, and tested. 1.5 APPLICABLE PUBLICATIONS A. Publications listed below (including amendments, addenda, revisions, supplements, and errata) form a part of this specific

11、ation to the extent referenced. Publications are referenced in the text by designation only. B. American Concrete Institute (ACI): Building Code Requirements for Structural Concrete 318/318M-05 Building Code Requirements for Structural Concrete & Commentary SP-66-04 . ACI Detailing Manual C. America

12、n National Standards Institute (ANSI): 77-07 Underground Enclosure Integrity D. American Society for Testing and Materials (ASTM): C478-09 Standard Specification for Precast Reinforced Concrete Manhole Sections C858-09 Underground Precast Concrete Utility Structures C990-09 Standard Specification fo

13、r Joints for Concrete Pipe, Manholes and Precast Box Sections Using Preformed Flexible Joint Sealants. E. Institute of Electrical and Electronic Engineers (IEEE): C2-07 National Electrical Safety Code Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-0

14、9-10 26 05 41 - 3 F. National Electrical Manufacturers Association (NEMA): TC 2-03 Electrical Polyvinyl Chloride (PVC) Tubing And Conduit TC 3-2004 PVC Fittings for Use With Rigid PVC Conduit And Tubing TC 6 & 8 2003 PVC Plastic Utilities Duct For Underground Installations TC 9-2004 Fittings For PVC

15、 Plastic Utilities Duct For Underground Installation G. National Fire Protection Association (NFPA): 70-08 National Electrical Code (NEC) H. Underwriters Laboratories, Inc. (UL): 6-07 . Electrical Rigid Metal Conduit-Steel 467-07 . Grounding and Bonding Equipment 651-05 . Schedule 40 and 80 Rigid PV

16、C Conduit and Fittings 651A-00 Type EB and A Rigid PVC Conduit and HDPE Conduit 651B-07 Continuous Length HDPE Conduit I. U.S. General Services Administration (GSA): A-A-60005-1998 . Frames, Covers, Gratings, Steps, Sump and Catch Basin, Manhole 1.6 STORAGE Lift and support pre-cast concrete structu

17、res only at designated lifting or supporting points. PART 2 - PRODUCTS SPEC WRITER NOTES: 1. Make material requirements agree with applicable requirements specified in the referenced Applicable Publications. Update and specify only that which applies to the project. 2. This specification is intended

18、 to be used in concert with VA manhole and pullbox Standard Details. Include details on plans and edit details as necessary to fit project needs. 2.1 PRE-CAST CONCRETE MANHOLES AND HARDWARE A. Structure: Factory-fabricated, reinforced-concrete, monolithically-poured walls and bottom. Frame and cover

19、 shall form top of manhole. Comply with ASTM C 858. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 05 41 - 4 B. Cable Supports: 1. Cable stanchions shall be hot-rolled, heavy duty, hot-dipped galvanized “T“ section steel, 2.25 in 56 mm x 0.

20、25 in 6 mm in size, and punched with 14 holes on 1.5 in 38 mm centers for attaching cable arms. 2. Cable arms shall be 0.1875 in 5 mm gauge, hot-rolled, hot-dipped galvanized sheet steel, pressed to channel shape. Arms shall be approximately 2.5 in 63 mm wide x 14 in 350 mm long. 3. Insulators for c

21、able supports shall be high-glazed, wet process porcelain, and shall completely encircle the cable. 4. Equip each cable stanchion with two spare cable arms and six spare insulators for future use. SPEC WRITER NOTE: Edit paragraph below to conform to project requirements. C. Ladder: /Aluminum/ /Fiber

22、glass/ with 16 in 400 mm rung spacing. Provide securely-mounted ladder for every manhole over 4 ft 1.2 M deep. D. Ground Rod Sleeve: Provide a 3 in 75 mm PVC sleeve in manhole floors so that a driven ground rod may be installed. E. Sump: Provide 12 in x 12 in 305 mm x 305 mm covered sump frame and c

23、over. 2.2 PULLBOXES SPEC WRITER NOTE: Edit paragraphs below to conform to project requirements. A. General: Size as indicated on drawings. Provide pullboxes with weatherproof, non-skid covers with recessed hook eyes, secured with corrosion- and tamper-resistant hardware. Cover material shall be iden

24、tical to pullbox material. Covers shall have molded lettering, ELECTRIC or SIGNAL as applicable. Pullboxes shall comply with the requirements of ANSI/SCTE 77 /Tier 5/ /Tier 8/ /Tier 15/ /Tier 22/ loading. Provide pulling irons, 0.875 in 22 mm diameter galvanized steel bar with exposed triangular-sha

25、ped opening. /B. Polymer Concrete Pullboxes: Shall be molded of sand, aggregate, and polymer resin, and reinforced with steel, fiberglass, or both. Pullbox shall have open bottom./ /C. Fiberglass Pullboxes: Shall be sheet-molded, fiberglass-reinforced, polyester resin enclosure joined to polymer con

26、crete top ring or frame./ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 05 41 - 5 /D. Concrete Pullboxes: Shall be monolithically-poured reinforced concrete./ SPEC WRITER NOTE: Include VA duct Standard Detail on plans. 2.3. DUCTS A. Number

27、 and sizes shall be as shown on drawings. B. Ducts (concrete-encased): 1. Plastic Duct: a. / NEMA TC6 & 8 and TC9 plastic utilities duct / / UL 651 and 651A Schedule 40 PVC /. b. Duct shall be suitable for use with 194 F 90 C rated conductors. 2. Conduit Spacers: Prefabricated plastic. C. Ducts (dir

28、ect-burial): 1. Plastic duct: a. NEMA TC2 and TC3 b. UL 651, 651A, and 651B, / Schedule 40 / / Schedule 80 / PVC or HDPE. c. Duct shall be suitable for use with 167 F 75 C rated conductors. 2. Rigid metal conduit: UL6 and NEMA RN1 galvanized rigid steel, threaded type, half-lapped with 10 mil PVC ta

29、pe. 2.4 GROUNDING A. Rods: Per Section 26 05 26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS. B. Ground Wire: Stranded bare copper 6 AWG 16 mm minimum. 2.5 WARNING TAPE Standard 4-mil polyethylene 3 in 76 mm wide detectable tape, red with black letters, imprinted with “CAUTION - BURIED ELECTRIC CAB

30、LE BELOW” or similar. 2.6 PULL ROPE FOR SPARE DUCTS Plastic with 200 lb 890 N minimum tensile strength. PART 3 - EXECUTION 3.1 MANHOLE AND PULLBOX INSTALLATION A. Assembly and installation shall follow the printed instructions and recommendations of the manufacturer. Install manholes and pullboxes l

31、evel and plumb. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 05 41 - 6 1. Units shall be installed on a 12 in 300 mm level bed of 90% compacted granular fill, well-graded from the 1 in 25 mm sieve to the No. 4 sieve. Granular fill shall b

32、e compacted with a minimum of four passes with a plate compactor. 2. Seal duct terminations so they are watertight. B. Access: Ensure the top of frames and covers are flush with finished grade. C. Ground Rods in Manholes: Drive a ground rod into the earth, through the floor sleeve, after the manhole

33、 is set in place. Fill the sleeve with sealant to make a watertight seal. Rods shall protrude approximately 4 in 100 mm above the manhole floor. D. Grounding in Manholes: 1. Install a No. 3/0 AWG 95 mm bare copper ring grounding conductor around the inside perimeter of the manhole and anchor to the

34、walls with metallic cable clips. 2. Connect the ring grounding conductor to the ground rod by an exothermic welding process. 3. Bond the ring grounding conductor to the duct bank equipment grounding conductors, the exposed non-current carrying metal parts of racks, sump covers, and like items in the

35、 manholes with a minimum No. 6 AWG 16 mm bare copper jumper. SPEC WRITER NOTE: Remove paragraphs below if not required by project. Include illumination in manholes close to an electrical power source. Include sump pump circuit in manholes subject to flooding. Show circuits on plans. /E. Manhole Ligh

36、ting: Provide NEMA 3R lighting switch mounted no more than 2 ft 0.6 M from top of ladder and a 27 W compact fluorescent wet location light fixture in manhole. Provide dedicated 0.75 in 20 mm direct-buried conduit and conductors to nearest electrical panel board./ /F. Sump Pump: Provide sump pump com

37、plete with float switch, GFCI receptacle, and T-rated switch in NEMA 3R boxes in manhole. Provide dedicated 0.75 in 20 mm direct-buried conduit and conductors to nearest electrical panelboard./ 3.2 TRENCHING SPEC WRITER NOTE: Edit paragraph below to conform to project requirements. Provided by IHSNo

38、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 05 41 - 7 A. Refer to /Section 31 20 00, EARTH MOVING/ /Section 31 20 11 EARTH MOVING (SHORT FORM)/ for trenching, backfilling, and compaction. B. Before performing trenching work at existing facilities, the Gr

39、ound Penetrating Radar Survey shall be carefully performed by certified technician to reveal all existing underground ducts, conduits, cables, and other utility systems. C. Work with extreme care near existing ducts, conduits, cables, and other utilities to avoid damaging them. D. Cut the trenches n

40、eatly and uniformly. E. For Concrete-Encased Ducts: 1. After excavation of the trench, stakes shall be driven in the bottom of the trench at 4 ft 1.2 M intervals to establish the grade and route of the duct bank. 2. Pitch the trenches uniformly toward manholes or both ways from high points between m

41、anholes for the required duct line drainage. Avoid pitching the ducts toward buildings wherever possible. 3. The walls of the trench may be used to form the side walls of the duct bank, provided that the soil is self-supporting and that concrete envelope can be poured without soil inclusions. Forms

42、are required where the soil is not self-supporting. 4. After the concrete-encased duct has sufficiently cured, the trench shall be backfilled to grade with earth, and appropriate warning tape installed. F. Conduits to be installed under existing paved areas and roads that cannot be disturbed shall b

43、e jacked into place. Conduits shall be heavy wall rigid steel. 3.3 DUCT INSTALLATION A. General Requirements: 1. Ducts shall be in accordance with the NEC and IEEE C2, as shown on the drawings, and as specified. 2. Slope ducts to drain towards manholes and pullboxes, and away from building and equip

44、ment entrances. Pitch not less than 4 in 100 mm in 100 ft 30 M. 3. Underground conduit stub-ups and sweeps to equipment inside of buildings shall be taped galvanized rigid steel, and shall extend a minimum of 5 ft 1.5 M outside the building foundation. Tops of conduits below building slab shall be m

45、inimum 24 in 610 mm below bottom of slab. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 05 41 - 8 4. Stub-ups, sweeps, and risers to equipment mounted on outdoor concrete slabs shall be taped galvanized rigid steel, and shall extend a mini

46、mum of 5 ft 1.5 M away from the edge of slab. 5. Install insulated grounding bushings on the terminations. 6. Radius for turns of direction shall be sufficient to accomplish pulls without damage. Minimum radius shall be six times conduit diameter. Use manufactured long sweep bends. 7. Additional bur

47、ial depth shall be required in order to accomplish NEC-required minimum bend radius of ducts. 8. All multiple conduit runs shall have conduit spacers. Spacers shall securely support and maintain uniform spacing of the duct assembly a minimum of 3 in 75 mm above the bottom of the trench during the co

48、ncrete pour. Spacer spacing shall not exceed 5 ft 1.5 M. Secure spacers to ducts and earth to prevent floating during concrete pour. Provide nonferrous tie wires to prevent displacement of the ducts during pouring of concrete. Tie wires shall not act as substitute for spacers. 9. Duct lines shall be installed no less than 12 in 300 mm from other utility systems, such as water, sewer, and chilled water. 10. Clearances between individual ducts: a. For like services, not less than 3 in 75 mm. b. For power and signal services, not less than 6 in 150 mm. 11. Duct