616Conduits and Pull Boxes

616.01 Description

This work is furnishing and installing plastic and steel electrical conduit, including fittings, junction boxes, pull boxes, and accessories.

616.02 Materials

Furnish materials in accordance with the following subsection requirements: Conduit ................................................................... 703.02 Pull Boxes ............................................................... 703.03

616.03 Construction Requirements

616.03.1 General

Install conduit and pull boxes in accordance with the NEC. Conduit lengths in the contract are estimated, and may require changes, approved by the Project Manager, to avoid underground obstructions. Refer to Subsection 107.18 regarding locating of underground utilities before excavation. Provide the specified conduit type and size or substitute a larger size conduit at Contractor expense. Do not change conduit size within any conduit run. Use minimum 2-inch (53 mm) diameter conduit between pull boxes and adjacent standard bases. Have conduit enter the foundation at least 24 inches (610 mm) below the top. Conduit stubs on structures are specified in the contract. Place and securely hold in position conduit ends, anchor bolts, and other fittings set in concrete until the concrete sets. Lay conduit a minimum of 18 inches (455 mm) below the curb grade in sidewalk areas and not less than 24 inches (610 mm) below the finished grade in all other areas. Install conduits under railroad tracks to railroad company requirements. Notify the Department and the railroad company at least 48 hours before starting work on railroad property. Terminate conduit in standard or pedestal foundations at least 3 inches (75 mm) above the foundation top. Keep conduit within foundations at least 6 inches (150 mm) from the foundation face. Extend conduit terminating in standards or pedestals above the foundation and slope it towards the handhole opening. Terminate conduit entering concrete pull boxes 2 inches (50 mm) inside the box wall, at least 2 inches (50 mm) above the bottom and slope it to aid cable pulling. Locate conduit entrances in pull box bottoms near the end walls leaving most of the box clear. Install conduit outlets in the box from the direction of the run. Seal conduit leading into socket walls, lights, or fixtures below the pull box grade using a watertight sealing compound. Install a pull wire in all unused conduits over 10 feet (3 m) long. Double at least 2 feet (610 mm) of pull wire back into the conduit at each termination point for runs over 100 feet (30.5 m); double 1-foot (305 mm) back for shorter runs. Install a conduit expansion joint, detailed in the contract, where the conduit crosses a fixed or structure expansion joint. Equip each expansion fitting with a grounding strap jumper. Thoroughly clean contact areas before clamping grounding straps. Secure all conduit bonds, lighting bracket anchor bolts, and bridge rail anchor bolts to form a continuous mechanical and electrical system. When not included as part of a new foundation, 616 – CONDUITS AND PULL BOXES 2020 EDITION V5.1 616-2 furnish, install, and pay for all work and materials (such as grounding straps and bare AWG No. 6 wire) necessary to make a continuous grounded system as part of the unit price for conduit. Clean out existing underground conduit incorporated into new conduit with compressed air and mandrel for size if required. Install pull boxes and conduits as specified with the pull box covers flush with the concrete facing or as directed. Compact backfill material for conduit trenches constructed outside of the roadbed sections to the density of the adjacent material. Restore existing surfaces disturbed by conduit or pull box installations to the original type and condition. Push or bore conduit under existing roadways. Install conduit that is to be under new surfacing prior to new surfacing being put in place. Keep jacking and drilling pits at least 2 feet (610 mm) away from the roadway surface edge. Do not undermine the roadway surface or soften subgrade when using water. Open cutting across the existing roadway will be allowed only after 3 unsuccessful attempts at conduit installation using either a fluid assisted directional boring system with a minimum push and pull back force of 4,946 lbf (22 kN), or a directional rod pusher with a minimum push and pull back force of 38,217 lbf (170 kN). The Project Manager may approve cutting small test holes in the roadway surface to locate obstructions. When approved by the Project Manager, trench across paved roadways without disturbing or injuring the paved surface on both sides of the trench. Cut asphalt pavements leaving a straight cut face. Excavate, install conduit, and backfill with approved material. Fill the top 1-foot (305 mm) of the trench with compacted plant mix or as directed. Replace all damaged pavement. Fill open cuts across roadways with CLSM in accordance with the contract. Furnish and place CLSM as an alternative to compacted soil to the lines and grades shown in the contract. Submit a mix design and furnish CLSM in accordance with Section 551 . Payment for all costs associated with furnishing and placing CLSM is included as part of the conduit bid item.

616.03.2 Plastic Conduit

Excavate trenches for plastic conduit a minimum 24 inches (610 mm) deep. Tamp the trench bottom and bed with 2 inches (50 mm) of sand before laying the conduit. Once the conduit is placed, place compact sand, or soil free of rocks or hard lumps, 6 inches (150 mm) above the pipe. Complete the backfill using material passing a minus 3-inch (75 mm) screen. Join conduit using a solvent-welded slip-fitter coupling to provide a watertight joint. Separate plastic parallel and perpendicular conduit runs from each other with at least 3 inches (75 mm) of sand or soil cushion. Cap open ends of conduit to prevent moisture, dirt, or rocks from entering the conduit. For plastic conduit runs 300 feet (91 m) or longer, leave one end disconnected or insert an “O” ring expansion coupling near one end of the run.

616.03.3 Steel Conduit

Install rigid conduit in accordance with the NEC article 346. Make field cuts square and true so that the ends join full circumference. Ream the conduit ends to remove burrs and rough edges. 2020 EDITION V5.1 CONDUITS AND PULL BOXES – 616 616-3 Slip joints or running threads are not permitted for coupling conduit. Use an approved threaded union coupling when a standard coupling cannot be used. Coat any new threads on conduit with a cold galvanizing compound before making couplings. Tighten couplings until the conduit ends are brought together making a good electrical connection throughout the entire conduit run. Paint damaged conduit coating with a cold galvanizing compound. Thread and cap conduit with standard pipe caps until the wiring is placed. Install insulated grounding bushings when caps are removed. Connect new steel conduit directly to stubs of existing steel conduit protruding from existing foundations and at nearest coupling points. New threaded joints may be approved by the Project Manager if the above requirements are met. Do not use plastic conduit in the system. Make conduit field bends having a minimum radius of six times the inside diameter of the conduit. Factory conduit bends must not crimp or flatten the conduit and use the longest practical radius.

616.03.4 Pull Boxes and Manholes

Construct and install pull boxes and manholes as specified. The Contractor may install additional pull boxes to aid the work at the Contractor’s expense. Install pull boxes and manholes with covers level with curbs, sidewalks, and surrounding ground. Bed the box bottoms in concrete or crushed rock as specified. When replacing or adjusting an existing pull box, adjust conduit stub heights accordingly. When installing pull boxes in sidewalk, install so water runs away from the pull box lip. When installing pull boxes in open ground, encase pull box in a Class General concrete pad extending 12 inches (305 mm) horizontally away from the pull box in all directions and at least 12 inches (305 mm) deep. Prevent damage to any existing pull box to be re-used on this project. Any pull box damaged by the Contractor is to be replaced by the Contractor at no cost to the Department. This item includes all excavation, gravel base, the concrete pad around the pull box, placement of the pull box, electrical bonding of conduits, backfill, and repair of the surface and surrounding area.

616.04 Method of Measurement

616.04.1 Lump Sum Basis

When a conduit system or portion thereof is specified in the contract on a lump sum basis, the system is measured by the lump sum.

616.04.2 Conduit

Conduit is measured by the foot (m).

616.04.3 Pull Boxes and Manholes

Pull boxes and manholes are measured by the unit. 616 – CONDUITS AND PULL BOXES 2020 EDITION V5.1 616-4

616.05 Basis of Payment

Payment for the completed and accepted quantities is made under the following: Pay Item Pay Unit Conduit Foot (m) Conduit System Lump Sum Manhole Each Pull Box Each