This specification covers the furnishing and installation of complete raceway systems used to enclose and protect electrical conductors rated 1000V and below in commercial, institutional, and industrial construction. Raceway systems include rigid metal conduit, intermediate metal conduit, electrical metallic tubing, flexible metal conduit, liquidtight flexible metal and nonmetallic conduit, rigid polyvinyl chloride conduit, electrical nonmetallic tubing, surface metal and nonmetallic raceways, metal and nonmetallic wireways, and all associated fittings, connectors, outlet and junction boxes, conduit bodies, supports, and identification.
All raceway materials and installation shall comply with NFPA 70 (National Electrical Code), the applicable building code, and the requirements of the authority having jurisdiction. All raceway components shall be listed and labeled by a Nationally Recognized Testing Laboratory (NRTL) for the specific application and environment in which they are installed. Where a referenced standard and the NEC conflict, the more stringent requirement shall govern unless the Engineer directs otherwise in writing.
This standard establishes the type of raceway permitted in each location and environment, the methods for sizing raceway and limiting conductor fill, the requirements for supporting and securing raceway, and the procedures for routing, bending, sealing, firestopping, and proving raceway before conductors are installed. Conductors and cables pulled into the raceway are specified separately in Conductors And Cables. Equipment grounding conductors and the bonding of metallic raceway systems are coordinated with Grounding And Bonding.
This standard does not cover underground concrete-encased duct banks, busway, or cable tray used as a primary cable support system. It does not address raceway seals, fittings, or wiring methods unique to hazardous (classified) locations; where any portion of the work occurs in a classified location, the Contractor shall notify the Engineer and apply the additional requirements of NEC Chapter 5.
Raceway materials and installation shall comply with the latest edition of the following standards in effect at the time of bid, except where the contract documents specify a particular edition. Where conflicts exist between referenced standards, the more stringent requirement shall govern unless otherwise directed by the Engineer of Record.
| Standard | Title |
|---|---|
| NFPA 70 | National Electrical Code |
| NFPA 70E | Standard for Electrical Safety in the Workplace |
| UL 6 | Electrical Rigid Metal Conduit — Steel |
| UL 6A | Electrical Rigid Metal Conduit — Aluminum, Red Brass, and Stainless Steel |
| UL 1242 | Electrical Intermediate Metal Conduit — Steel |
| UL 797 | Electrical Metallic Tubing — Steel |
| UL 1 | Flexible Metal Conduit |
| UL 360 | Liquid-Tight Flexible Steel Conduit |
| UL 651 | Schedule 40, 80, Type EB and A Rigid PVC Conduit and Fittings |
| UL 1653 | Electrical Nonmetallic Tubing |
| UL 1660 | Liquid-Tight Flexible Nonmetallic Conduit |
| UL 5 | Surface Metal Raceways and Fittings |
| UL 5A | Nonmetallic Surface Raceways and Fittings |
| UL 870 | Wireways, Auxiliary Gutters, and Associated Fittings |
| UL 514A | Metallic Outlet Boxes |
| UL 514B | Conduit, Tubing, and Cable Fittings |
| UL 514C | Nonmetallic Outlet Boxes, Flush-Device Boxes, and Covers |
| UL 467 | Grounding and Bonding Equipment |
| ANSI C80.1 | Electrical Rigid Steel Conduit (ERSC) |
| ANSI C80.3 | Steel Electrical Metallic Tubing (EMT) |
| ANSI C80.6 | Electrical Intermediate Metal Conduit (EIMC) |
| NEMA TC 2 | Electrical Polyvinyl Chloride (PVC) Conduit |
| NEMA TC 3 | PVC Fittings for Use with Rigid PVC Conduit and Tubing |
| NEMA RN 1 | Polyvinyl Chloride (PVC) Externally Coated Galvanized Rigid Steel Conduit and Intermediate Metal Conduit |
| NEMA FB 1 | Fittings, Cast Metal Boxes, and Conduit Bodies for Conduit, EMT, and Cable |
| NECA 1 | Standard for Good Workmanship in Electrical Construction |
| NECA 101 | Standard for Installing Steel Conduit (Rigid, IMC, EMT) |
| NECA 102 | Standard for Installing Aluminum Rigid Metal Conduit |
| NECA 111 | Standard for Installing Nonmetallic Raceways (RNC, ENT, LFNC) |
| ASTM A123 | Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products |
| ASTM E814 | Fire Tests of Penetration Firestop Systems |
The Contractor shall submit the following for review and approval prior to ordering raceway materials or beginning installation:
The Contractor shall provide at substantial completion record (as-built) drawings indicating the actual routing, size, and type of all concealed, underground, and exposed raceway, the location of all pull boxes and junction boxes, and the location and type of all firestop systems. Where raceway routing differs from the contract drawings, the as-built documentation shall reflect the installed condition. Closeout submittals shall be coordinated with the project record documents required by the General Conditions.
Raceway systems shall be installed by electricians regularly engaged in commercial and industrial electrical construction and working under the supervision of a licensed electrical contractor. Installation workmanship shall meet or exceed NECA 1 and the applicable NECA installation standard for the raceway type (NECA 101 for steel conduit, NECA 102 for aluminum conduit, NECA 111 for nonmetallic raceways).
All raceway materials shall be listed and labeled by an NRTL for the intended use. The installation shall be inspected and approved by the authority having jurisdiction. The Contractor shall schedule rough-in inspections before concealed raceway is covered and shall not conceal any raceway until it has been inspected where inspection is required.
For each raceway type, fittings and connectors shall be of a design and material listed for use with that raceway. Steel conduit, fittings, and supports exposed to the weather or to corrosive conditions shall be of compatible materials to prevent galvanic corrosion. Mixing of dissimilar metals in direct contact shall be avoided; where unavoidable, an approved isolating fitting or coating shall be provided.
Raceway type selection is governed primarily by the environment in which the raceway is installed. The Contractor shall not substitute a raceway type that is not listed and permitted by the NEC for the specific location. The following conditions shall be evaluated for every raceway run.
Dry interior locations not subject to moisture, physical damage, or corrosion permit the widest range of raceway types, including EMT, IMC, RMC, rigid PVC, ENT (where concealed in permitted construction), surface raceways, and wireways. EMT is the standard raceway for exposed and concealed dry interior branch-circuit and feeder work in commercial buildings because it is economical, lightweight, and provides an equipment grounding path through its listed fittings.
In wet and damp locations, raceway, fittings, boxes, and supports shall be listed for wet-location use and installed to prevent the accumulation of water within the raceway system. Where raceway passes from a heated interior to an unheated or exterior space, condensation will form and drain within the raceway; the Contractor shall route raceway and locate drain points to prevent water from collecting at equipment or in low boxes. Per NEC 358.10, EMT may be installed in wet locations only where the fittings are identified for wet-location use and the raceway is supported away from masonry and concrete surfaces. RMC, IMC, and rigid PVC are suitable for wet locations.
In corrosive environments — coastal exposure, chemical processing areas, wastewater facilities, swimming pool equipment rooms, and similar — the Contractor shall provide raceway with corrosion resistance suitable for the specific exposure. Per NEC 300.6, metal raceway and supports shall be protected against corrosion. Options include PVC-coated rigid metal conduit conforming to NEMA RN 1, aluminum RMC, stainless steel RMC, or nonmetallic raceway. Where PVC-coated conduit is used, all field cuts, threads, and damaged coating shall be repaired with the manufacturer's patching compound to maintain the continuous coating.
Nonmetallic raceway exposed to direct sunlight shall be listed and marked as sunlight resistant. Rigid PVC conduit and PVC fittings exposed to sunlight shall be listed for the exposure; standard PVC conduit not so marked shall not be used in sunlight-exposed locations because UV degradation embrittles the material over time. The Contractor shall verify the sunlight-resistant marking on the conduit and fittings before installation in any exposed exterior location.
Raceway installed underground by direct burial shall be listed for direct burial and shall be installed at the minimum cover depth required by NEC 300.5. Permitted direct-burial raceways include RMC, IMC, rigid PVC (Schedule 40 and Schedule 80), HDPE conduit, and RTRC. PVC conduit is the most common direct-burial raceway for branch circuits and feeders; Schedule 80 PVC or RMC/IMC shall be used where the conduit emerges from the ground and is subject to physical damage, and at the transition fitting from underground to above-grade routing.
Burial cover depth shall comply with NEC Table 300.5 for the specific raceway type, circuit voltage, and location (under a building, under a driveway, under a roadway, or in open earth). The depth selected above shall be confirmed against the contract drawings and the governing NEC table; the more stringent value governs.
Raceway encased in concrete slabs or structural members shall be of a type permitted for the application and shall be installed so that the conduit does not displace required reinforcing steel or compromise the structural section. Rigid PVC, RMC, and IMC are commonly encased in concrete. Where raceway is embedded in a structural slab, the outside diameter of the conduit shall not exceed one-third of the slab thickness, and conduit shall be spaced and located as coordinated with the Structural Engineer. Underground concrete-encased duct banks are outside the scope of this standard; see Underground Ductbank.
In ducts, plenums, and other spaces used for environmental air, only wiring methods permitted by NEC 300.22 shall be installed. Metal raceway — EMT, IMC, RMC, FMC — and metal wireway are permitted in such spaces. Nonmetallic raceway, ENT, and surface nonmetallic raceway shall not be installed in plenums or environmental-air spaces unless specifically listed and permitted for that use. The Contractor shall confirm the plenum rating of any raceway routed above a suspended ceiling used as a return-air plenum.
This standard does not cover hazardous (classified) locations. Where any raceway is routed through or terminates in a Class I, II, or III location, the Contractor shall notify the Engineer and apply the sealing, fitting, and wiring-method requirements of NEC Articles 500 through 516.
Rigid metal conduit shall comply with UL 6 (steel) or UL 6A (aluminum, red brass, stainless steel) and, for steel RMC, the dimensional requirements of ANSI C80.1, and shall be installed per NEC Article 344. RMC is the heaviest-wall threaded metal conduit and provides the greatest mechanical protection. RMC is permitted in all atmospheric conditions and occupancies, including exposed exterior, wet, and direct-burial applications, and provides a code-recognized equipment grounding path. Steel RMC shall be hot-dip galvanized inside and out. Use RMC where conductors require maximum physical protection, at building entrances, in exposed exterior risers, and where the conduit is subject to severe physical damage.
Threadless (compression or set-screw) fittings are not permitted on RMC where a threaded connection is required for the application. Running threads shall not be used to couple conduit; use a listed three-piece (Erickson) coupling or split coupling instead.
Intermediate metal conduit shall comply with UL 1242 and the dimensional requirements of ANSI C80.6 and shall be installed per NEC Article 342. IMC has a thinner wall than RMC but the same outside diameter and is permitted in all the same applications as RMC, including exposed exterior, wet, and direct-burial use. IMC weighs roughly one-third less than RMC, which reduces material cost and installation labor. IMC may be used wherever RMC is permitted and is the recommended choice for exterior and physically exposed feeder runs where the additional wall thickness of RMC is not required.
Electrical metallic tubing shall comply with UL 797 and the dimensional requirements of ANSI C80.3 and shall be installed per NEC Article 358. EMT is an unthreaded thin-wall steel raceway and is the standard wiring method for concealed and exposed branch-circuit and feeder raceway in dry commercial interiors. EMT is lighter and faster to install than threaded conduit and, with listed fittings, provides an equipment grounding path.
Per NEC 358.12, EMT is not permitted where subject to severe physical damage. In areas such as loading docks, vehicle traffic zones, and exposed locations below 8 ft where impact is likely, the Contractor shall use RMC or IMC instead.
Per NEC 358.10, EMT fittings used in wet locations shall be identified for wet-location use. Set-screw fittings are permitted in dry locations; compression (gland) fittings, identified as raintight or concrete-tight, shall be used where the raceway is exposed to weather or embedded in concrete. Indenter-type fittings are not permitted.
Flexible metal conduit shall comply with UL 1 and shall be installed per NEC Article 348. FMC provides a flexible metallic raceway used to connect equipment subject to vibration or movement, to make final connections to recessed luminaires, and to accommodate equipment that must be removable for service. FMC shall not be used in wet locations, in concrete, or where subject to physical damage. Where FMC is used as an equipment grounding path, the length and conditions shall meet NEC 348.60; otherwise, a separate equipment grounding conductor shall be installed in the FMC.
Flexible connections to vibrating or adjustable equipment shall be long enough to absorb movement and permit equipment service but no longer than necessary. A flexible whip to a recessed luminaire is limited by NEC 410.117(C) to a maximum of 6 ft. Where FMC is relied on for equipment grounding, the total length in the ground-fault return path shall not exceed 6 ft.
Liquidtight flexible metal conduit shall comply with UL 360 and shall be installed per NEC Article 350. LFMC is a flexible metallic raceway with a liquidtight nonmetallic outer jacket, used for final connections to outdoor equipment, motors, transformers, rooftop units, and other equipment subject to vibration or located in wet or oily environments. LFMC shall be terminated with fittings listed for liquidtight use.
Liquidtight flexible nonmetallic conduit shall comply with UL 1660 and shall be installed per NEC Article 356. LFNC provides a flexible, corrosion-resistant, liquidtight connection where a metallic raceway is undesirable. Because LFNC contains no metallic path, a separate equipment grounding conductor shall always be installed within it.
Rigid polyvinyl chloride conduit shall comply with UL 651 and NEMA TC 2, fittings shall comply with NEMA TC 3, and the system shall be installed per NEC Article 352. Rigid PVC is a nonmetallic raceway widely used for underground, direct-burial, wet-location, and corrosive-area applications. Schedule 40 PVC is the standard wall thickness; Schedule 80 PVC has a thicker wall and shall be used where the conduit is exposed to physical damage, including at above-grade transitions from underground routing.
Because PVC conduit is nonconductive, it cannot serve as an equipment grounding path. Per NEC 250.118, an equipment grounding conductor sized per NEC Table 250.122 shall be pulled in every PVC raceway containing circuit conductors.
PVC conduit expands and contracts significantly with temperature change. Expansion fittings shall be provided as described in the expansion-fitting section below. Solvent-cemented joints shall be made with the cement listed for the conduit, with clean, square-cut, deburred ends, following the cement manufacturer's instructions for ambient temperature.
Electrical nonmetallic tubing shall comply with UL 1653 and shall be installed per NEC Article 362. ENT is a flexible, corrugated, nonmetallic raceway used concealed within walls, floors, and ceilings, and within concrete. ENT shall not be installed where exposed except as permitted by NEC 362.10, shall not be used in plenums or environmental-air spaces unless listed for that use, and shall not be used where ambient temperature exceeds its rating. A separate equipment grounding conductor shall be installed in every ENT run.
Surface metal raceway shall comply with UL 5 and be installed per NEC Article 386; surface nonmetallic raceway shall comply with UL 5A and be installed per NEC Article 388. Surface raceway is used for exposed extensions of branch circuits in finished spaces where concealment is impractical, such as adding receptacles or data outlets to existing masonry or finished walls. Surface raceway shall be installed in dry locations only and shall not be used where subject to severe physical damage, in plenums, or where concealed.
Metal wireway and nonmetallic wireway shall comply with UL 870 and be installed per NEC Article 376 (metal) or 378 (nonmetallic). Wireway is a sheet-metal or nonmetallic trough with a hinged or removable cover, used to consolidate and route large numbers of conductors between distribution equipment, in equipment rooms, and at gutter connections to panelboards. Per NEC 376.22, the sum of the cross-sectional areas of all contained conductors shall not exceed 20 percent of the interior cross-sectional area of a metal wireway. Where more than 30 current-carrying conductors are installed in a wireway, ampacity adjustment factors apply.
Fittings, connectors, and couplings shall comply with UL 514B and NEMA FB 1 and shall be of a type listed for the raceway with which they are used and for the location and environment of the installation. Connectors at boxes and enclosures shall maintain the mechanical integrity and, for metal raceway systems, the electrical continuity of the equipment grounding path.
Per NEC 300.4(G), where conductors size 4 AWG and larger enter a raceway in a cabinet, box, or enclosure, the conductors shall be protected from abrasion by a fitting providing a smooth, rounded insulating surface. Bushings shall be installed on all raceway terminations carrying these conductors.
Per NEC 250.97, raceway terminations at equipment operating over 250V to ground, and at terminations where concentric or eccentric knockouts compromise the bonding path, shall be bonded around the knockout with bonding bushings, bonding locknuts, or bonding jumpers. The Contractor shall provide bonding bushings at service equipment and at all terminations where standard locknut connections do not establish a reliable ground-fault current path. Coordinate bonding requirements with Grounding And Bonding.
Metallic boxes shall comply with UL 514A, nonmetallic boxes with UL 514C, and conduit bodies with UL 514B and NEMA FB 1. Boxes and conduit bodies shall be sized, located, and supported per NEC Article 314. The box or conduit body material shall match the environment: cast or sheet-metal boxes with gasketed covers for wet and exterior locations, and FS/FD cast boxes where the box is part of an exposed conduit system.
Per NEC 314.16, the number of conductors, devices, and fittings permitted in an outlet or device box is limited by the box volume and the volume allowance per conductor. The Contractor shall size boxes so the calculated fill does not exceed the box volume marked by the manufacturer. Overfilled boxes overheat conductors and make device installation unreliable.
Pull boxes, junction boxes, and conduit bodies containing conductors 4 AWG and larger shall meet the dimensional requirements of NEC 314.28. For straight pulls, the length of the box shall be at least 8 times the trade size of the largest raceway. For angle and U pulls, the distance from the raceway entry to the opposite wall shall be at least 6 times the trade size of the largest raceway, plus the sum of the remaining raceway diameters. Undersized pull boxes damage conductor insulation during pulling and exceed the allowable bend radius of large conductors.
Per NEC 314.29, boxes and conduit bodies shall be installed so the wiring inside is accessible without removing any part of the building or, in underground installations, without excavating paved areas. Boxes shall not be concealed behind finished surfaces.
Raceway shall be sized so that the conductors within it do not exceed the fill limits of NEC Chapter 9. Per NEC Chapter 9, Table 1, the maximum conductor fill is 53 percent of the raceway interior cross-sectional area for one conductor, 31 percent for two conductors, and 40 percent for three or more conductors. Conductor and raceway dimensions for fill calculations shall be taken from NEC Chapter 9, Tables 4, 5, and 8, or the prepared combinations in Annex C. Fill limits ensure heat dissipation and allow conductors to be pulled and withdrawn without damage to the insulation.
The Contractor shall not add conductors to a raceway beyond the indicated count or upsize conductors without verifying that the resulting fill remains within the Table 1 limit. Where the raceway size is not shown on the drawings, the Contractor shall size the raceway for the conductors indicated using the NEC fill tables.
Per NEC 310.15(C)(1), the ampacity of conductors shall be adjusted when more than three current-carrying conductors are installed in a single raceway. The Engineer shall account for this derating in feeder and branch-circuit sizing; the Contractor shall not combine circuits into a common raceway in a manner that exceeds the design assumptions without the Engineer's approval.
Although NEC permits 1/2 in. raceway for many branch circuits, a 3/4 in. minimum is recommended for homerun and feeder raceway and for any raceway that may be extended in the future, because the marginal cost is small and the additional capacity reduces fill conflicts.
Spare raceways stubbed from flush-mounted panelboards to an accessible ceiling space allow future circuits to be added without opening finished walls. Where spare raceways are provided, the Contractor shall install a pull string and cap each end. Spare raceway quantity and routing shall be as indicated on the panelboard schedules and electrical plans.
Raceway shall be securely fastened in place and supported independently of other systems. Raceway shall not be supported by ceiling grid wires, piping, ductwork, or another contractor's work, and shall not be used to support other raceways or equipment except as specifically permitted by the NEC. Supports shall be of a material and finish suitable for the environment; in wet and corrosive locations, supports, straps, and hardware shall be corrosion-resistant.
EMT shall be securely fastened within 3 ft of each outlet box, junction box, device box, cabinet, conduit body, or other termination, and supported at intervals not exceeding 10 ft, per NEC 358.30. RMC and IMC shall be fastened within 3 ft of each termination and supported at intervals not exceeding the distances in NEC Table 344.30(B)(2) and NEC 342.30, generally 10 ft for the larger trade sizes. Rigid PVC conduit shall be supported at the closer intervals of NEC Table 352.30 because PVC is less rigid than metal conduit. Flexible conduits shall be supported per NEC 348.30 (FMC) and 350.30 (LFMC), generally within 12 in. of each termination and at 4.5 ft intervals.
Grouped parallel raceway runs shall be supported on trapeze hangers or channel strut sized for the combined load. Threaded rod and channel strut shall be sized for the supported weight with an appropriate safety factor. In areas subject to seismic design requirements, raceway support and bracing shall comply with the seismic provisions of the applicable building code and ASCE 7.
Vertical raceway shall be secured at the top and supported at intervals that prevent the weight of the raceway and conductors from bearing on fittings. Where conductors rise vertically, conductor supports per NEC 300.19 shall be provided at the spacing required for the conductor size.
Per NEC 300.7(B), raceway shall be provided with expansion fittings, expansion-deflection fittings, or deflection fittings where necessary to compensate for thermal expansion and contraction and for structural movement.
Where any raceway crosses a structural expansion joint, seismic joint, or settlement joint, the Contractor shall install an expansion-deflection fitting that accommodates movement in the required directions. The bonding jumper across the fitting shall maintain electrical continuity of the equipment grounding path. Joint locations are as indicated on the structural and architectural drawings.
Rigid PVC conduit has a coefficient of thermal expansion roughly five times that of steel. Per NEC 352.44, expansion fittings shall be provided for PVC conduit where the expected length change due to temperature variation is 1/4 in. or more. The Contractor shall calculate the expected length change from the installed-to-operating temperature differential and the run length, set the expansion fitting piston at installation per the manufacturer's temperature chart, and locate fittings so each conduit segment can move freely. Long exposed exterior PVC runs and PVC risers are the most common locations where expansion fittings are omitted in error, resulting in pulled joints and broken conduit.
Metallic raceway systems and the equipment grounding path within them shall be electrically continuous and shall be bonded to provide an effective ground-fault current path per NEC 250.4 and NEC Article 250, Part V.
All metal raceway, fittings, boxes, and enclosures shall be joined so the assembly is electrically continuous from every point in the system to the grounding electrode system. Listed RMC, IMC, and EMT with listed fittings are recognized equipment grounding conductors per NEC 250.118; however, the Contractor shall verify that every coupling and connector is fully made up and that locknuts are seated through clean knockouts.
Rigid PVC, ENT, RTRC, HDPE, and LFNC do not provide a metallic grounding path. An equipment grounding conductor sized per NEC Table 250.122 shall be installed in every nonmetallic raceway containing circuit conductors.
Per NEC 250.118, FMC and LFMC qualify as equipment grounding conductors only within specified length, trade size, and overcurrent-protection limits. Where the installation exceeds those limits, where flexibility is required after installation, or where the circuit serves equipment requiring a reliable ground, the Contractor shall install a separate equipment grounding conductor within the flexible conduit.
Installing a separate equipment grounding conductor in all raceways — including metallic raceway that would otherwise qualify on its own — provides a low-impedance, redundant ground-fault path that does not depend on the long-term integrity of every threaded and mechanical raceway joint. This practice is recommended for feeders, for circuits serving sensitive equipment, and where the project requires the highest reliability. The selected method shall be coordinated with Grounding And Bonding.
Raceway shall be routed parallel and perpendicular to building lines, concealed in finished areas, and grouped where practical for orderly installation and support. Routing shall avoid mechanical and plumbing equipment, maintain access to valves, dampers, and other serviceable equipment, and preserve the working clearances required at electrical equipment by NEC 110.26. Raceway routing shown on the drawings is diagrammatic; the Contractor shall route raceway to suit field conditions while meeting all support, bend, and fill requirements. Raceway shall be installed as coordinated with the reflected ceiling plans and structural framing.
Per NEC 300.18, raceway shall be installed as a complete system before conductors are pulled in. Conductors shall not be used as a means to assemble or support the raceway.
The Contractor shall cap or plug all raceway openings during construction to keep out water, concrete, dust, and debris. Raceway found with water or debris inside shall be cleaned and swabbed before conductors are installed.
Per NEC 358.26 (EMT), 344.26 (RMC), 342.26 (IMC), 352.26 (PVC), and the corresponding articles for other raceway types, the sum of all bends between a raceway's pull points — outlet to outlet, fitting to fitting, or outlet to fitting — shall not exceed 360 degrees, equivalent to four quarter-bends. Where a run would require more than 360 degrees of bend, the Contractor shall install an additional pull point. Excessive cumulative bending makes conductors impossible to pull without damaging the insulation.
Field bends shall be made with a bender designed for the raceway type and trade size and shall meet the minimum radius of NEC Chapter 9, Table 2. PVC conduit shall be bent only with equipment designed to heat the conduit uniformly; scorched or flattened PVC bends shall be rejected.
The Contractor shall provide pull boxes, junction boxes, or conduit bodies at intervals that limit raceway runs to the 360-degree bend rule and to a length that conductors can be pulled without exceeding their maximum pulling tension and sidewall pressure. Pull points shall be located in accessible spaces and sized per NEC 314.28.
Conductors shall be pulled into raceway using a listed wire-pulling lubricant compatible with the conductor insulation and the raceway material. Pulling tension and sidewall bearing pressure shall not exceed the conductor manufacturer's limits. Conductor installation is further specified in Conductors And Cables.
Per NEC 300.7(A), where a raceway is exposed to widely different temperatures — such as a raceway entering a refrigerated space, a building from outdoors, or a heated space from an unheated attic — the raceway shall be sealed to prevent circulation of warm air to a colder section, which causes condensation inside the raceway. Approved duct-sealing compound shall be installed in the raceway at the point of transition.
Where raceway penetrates a fire-rated or smoke-rated wall, floor, or ceiling, the Contractor shall restore the rating of the assembly using a firestop system tested per ASTM E814 (UL 1479) and listed for the specific penetrant, opening size, and assembly construction. The installed firestop system shall provide an F-rating and, where required, a T-rating not less than the rating of the penetrated assembly. The Contractor shall maintain documentation of the firestop system used at each penetration for the project record. Firestopping coordinates with the fire-rated assembly requirements of the architectural drawings.
The Contractor shall verify that every underground and concealed raceway run is clear, continuous, and free of obstruction, water, and debris before pulling conductors. Underground PVC and direct-burial raceway shall be proved by pulling a mandrel — a rigid cylinder approximately 1/4 in. smaller than the raceway interior diameter — completely through each run, followed by a swab. A raceway that does not pass the mandrel shall be excavated and corrected.
For metallic raceway systems relied upon as the equipment grounding conductor, the Contractor shall verify electrical continuity of the raceway path from equipment enclosures back to the grounding electrode system. Loose couplings, missing locknuts, and unbonded knockouts that interrupt the path shall be corrected. Grounding system testing is coordinated with Grounding And Bonding.
The Contractor shall request inspection of rough-in raceway by the authority having jurisdiction, and by the Engineer where required, before concealed raceway is covered. Raceway concealed without required inspection shall be uncovered at the Contractor's expense.
Per NEC 314.44, the cover of each junction box, pull box, and conduit body shall be marked to identify the system or circuits enclosed. Covers for boxes serving systems other than normal power — emergency power, fire alarm, or low-voltage systems — shall be marked or color-coded to distinguish them and shall comply with the marking requirements of the applicable NEC article for that system.
Empty and spare raceways shall be labeled at each end to indicate the origin and destination of the raceway, and shall contain a pull string for future use.
Raceway, fittings, and boxes shall be delivered to the site in the manufacturer's original packaging with listing labels intact. Materials shall be stored to prevent damage, corrosion, and UV degradation. PVC conduit and nonmetallic raceway shall be stored out of direct sunlight and supported to prevent bowing and deformation. Conduit threads and coatings shall be protected from damage; PVC-coated conduit shall be handled to avoid nicking or scraping the coating. Damaged raceway, fittings, or coatings shall not be installed.
The Contractor shall warrant the raceway installation against defects in materials and workmanship for the warranty period, beginning at substantial completion. The warranty shall cover correction of raceway found to be improperly sized, supported, sealed, bonded, or firestopped, and replacement of corroded or degraded raceway resulting from installation of a raceway type not suited to its environment.