1 Scope
NOTE 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. (1.1)
NOTE 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. (1.2)
NOTE 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. (1.3)
NOTE Conductors and cables pulled into the raceway are specified separately in
Conductors And Cables.
(1.4) 1.6 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.
1.7 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.
1.8 Where a referenced standard and the NEC conflict, the more stringent requirement shall govern unless the Engineer directs otherwise in writing.
1.9 Exclusions
NOTE This standard does not cover underground concrete-encased duct banks, busway, or cable tray used as a primary cable support system. (1.9.1)
NOTE It does not address raceway seals, fittings, or wiring methods unique to hazardous (classified) locations. (1.9.2)
1.9.3 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.
2 Referenced Standards
2.1 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.
2.2 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 |
3 Submittals
3.1 Action Submittals
3.1.1 The Contractor shall submit the following for review and approval prior to ordering raceway materials or beginning installation:
- Product data sheets for each raceway type, fitting, connector, box, conduit body, and support component proposed for use, identifying the manufacturer, catalog designation, material, and applicable listing.
- A raceway schedule correlating each raceway type to the locations and environments where it will be installed, demonstrating that the proposed type is permitted for each application by the NEC and this standard.
- Manufacturer's data confirming the listing and corrosion classification of any raceway proposed for a wet, corrosive, sunlight-exposed, or direct-burial location.
- Product data for firestop systems proposed at fire-rated and smoke-rated penetrations, including the tested system designation and rating.
- Shop drawings for any field-fabricated wireway, surface raceway layout, or large pull box not detailed on the contract drawings.
☑ Product data for each raceway type and fitting
☐ Raceway-to-application schedule
☐ Corrosion and environmental listing documentation
☐ Firestop system data sheets
☐ Field-fabricated wireway and pull box shop drawings
☐ Expansion fitting selection and setting calculations
☐ Support and seismic bracing details
3.2 Closeout Submittals
3.2.1 The Contractor shall provide the following at substantial completion, reflecting the installed condition where raceway routing differs from the contract drawings, and coordinated with the project record documents required by the General Conditions:
- Record (as-built) drawings indicating the actual routing, size, and type of all concealed, underground, and exposed raceway
- Location of all pull boxes and junction boxes
- Location and type of all firestop systems
☑ Record (as-built) raceway routing, size, and type drawings
☑ Pull box and junction box location records
☑ Firestop system location and type records
4 Quality Assurance
4.1 Installer Qualifications
4.1.1 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.
4.1.2 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).
4.2 Regulatory Requirements
4.2.1 All raceway materials shall be listed and labeled by an NRTL for the intended use.
4.2.2 The installation shall be inspected and approved by the authority having jurisdiction.
4.2.3 The Contractor shall schedule rough-in inspections before concealed raceway is covered.
4.2.4 The Contractor shall not conceal any raceway until it has been inspected where inspection is required.
4.3 Source Limitations
4.3.1 For each raceway type, fittings and connectors shall be of a design and material listed for use with that raceway.
4.3.2 Steel conduit, fittings, and supports exposed to the weather or to corrosive conditions shall be of compatible materials to prevent galvanic corrosion.
4.3.3 Mixing of dissimilar metals in direct contact shall be avoided.
4.3.4 Where contact between dissimilar metals is unavoidable, an approved isolating fitting or coating shall be provided.
5 Environmental and Service Conditions
NOTE Raceway type selection is governed primarily by the environment in which the raceway is installed. (5.1)
5.2 The following conditions shall be evaluated for every raceway run.
5.3 The Contractor shall not substitute a raceway type that is not listed and permitted by the NEC for the specific location.
5.4 Dry Locations
NOTE 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. (5.4.1)
NOTE 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. (5.4.2)
5.5 Wet and Damp Locations
NOTE Where raceway passes from a heated interior to an unheated or exterior space, condensation will form and drain within the raceway. (5.5.1)
5.5.2 The Contractor shall route raceway and locate drain points to prevent water from collecting at equipment or in low boxes.
○ Rigid metal conduit (RMC), hot-dip galvanized
● Intermediate metal conduit (IMC), hot-dip galvanized
○ Rigid PVC conduit, Schedule 40
○ Rigid PVC conduit, Schedule 80 (where physical damage is a concern)
5.5.3 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.
5.5.4 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.
5.5.5 RMC, IMC, and rigid PVC are suitable for wet locations.
5.6 Corrosive Locations
5.6.1 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.
NOTE Options include PVC-coated rigid metal conduit conforming to NEMA RN 1, aluminum RMC, stainless steel RMC, or nonmetallic raceway. (5.6.2)
None — interior, climate-controlled, non-corrosive
Mild — interior, unconditioned, occasional moisture
Moderate — exterior, coastal proximity, road-salt exposure
Severe — chemical process, wastewater, marine, direct chemical contact
PVC-coated rigid metal conduit (NEMA RN 1)
Aluminum rigid metal conduit (UL 6A)
Stainless steel rigid metal conduit (UL 6A)
Rigid PVC conduit, Schedule 80
Reinforced thermosetting resin conduit (RTRC)
5.6.3 Per NEC 300.6, metal raceway and supports shall be protected against corrosion.
5.6.4 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.
5.7 Sunlight and UV Exposure
5.7.1 Standard PVC conduit not marked sunlight resistant shall not be used in sunlight-exposed locations because UV degradation embrittles the material over time.
5.7.2 Nonmetallic raceway exposed to direct sunlight shall be listed and marked as sunlight resistant.
5.7.3 Rigid PVC conduit and PVC fittings exposed to sunlight shall be listed for the exposure.
5.7.4 The Contractor shall verify the sunlight-resistant marking on the conduit and fittings before installation in any exposed exterior location.
5.8 Direct Burial
NOTE Permitted direct-burial raceways include RMC, IMC, rigid PVC (Schedule 40 and Schedule 80), HDPE conduit, and RTRC. (5.8.1)
NOTE PVC conduit is the most common direct-burial raceway for branch circuits and feeders. (5.8.2)
5.8.3 The burial cover depth selected below shall be confirmed against the contract drawings and the governing NEC table; the more stringent value governs.
636
61218243036
Default: 24 in
Per drawings
5.8.4 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.
5.8.5 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.
5.8.6 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).
5.9 Concrete Encasement
NOTE Rigid PVC, RMC, and IMC are commonly encased in concrete. (5.9.1)
NOTE Underground concrete-encased duct banks are outside the scope of this standard; see
Underground Ductbank.
(5.9.2) 5.9.3 Raceway encased in concrete slabs or structural members shall be of a type permitted for the application.
5.9.4 Raceway encased in concrete shall be installed so that the conduit does not displace required reinforcing steel or compromise the structural section.
5.9.5 Where raceway is embedded in a structural slab, the outside diameter of the conduit shall not exceed one-third of the slab thickness.
5.9.6 Conduit embedded in a structural slab shall be spaced and located as coordinated with the Structural Engineer.
5.10 Plenums and Air-Handling Spaces
NOTE Metal raceway — EMT, IMC, RMC, FMC — and metal wireway are permitted in spaces used for environmental air. (5.10.1)
5.10.2 In ducts, plenums, and other spaces used for environmental air, only wiring methods permitted by NEC 300.22 shall be installed.
5.10.3 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.
5.10.4 The Contractor shall confirm the plenum rating of any raceway routed above a suspended ceiling used as a return-air plenum.
5.11 Classified Locations
NOTE This standard does not cover hazardous (classified) locations. (5.11.1)
5.11.2 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.
6 Raceway Types and Applications
NOTE RMC is the heaviest-wall threaded metal conduit and provides the greatest mechanical protection. (6.1.1)
NOTE 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. (6.1.2)
NOTE 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. (6.1.3)
● Hot-dip galvanized steel
○ Aluminum
○ PVC-coated galvanized steel (NEMA RN 1)
○ Stainless steel
6.1.4 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.
6.1.5 Steel RMC shall be hot-dip galvanized inside and out.
6.1.6 RMC fittings and couplings shall be threaded type listed for use with rigid metal conduit.
6.1.7 Threadless (compression or set-screw) fittings shall not be used on RMC where a threaded connection is required for the application.
6.1.8 Running threads shall not be used to couple conduit; a listed three-piece (Erickson) coupling or split coupling shall be used instead.
NOTE 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. (6.2.1)
NOTE IMC weighs roughly one-third less than RMC, which reduces material cost and installation labor. (6.2.2)
6.2.3 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.
6.2.4 Intermediate metal conduit shall comply with UL 1242 and the dimensional requirements of ANSI C80.6 and shall be installed per NEC Article 342.
NOTE 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. (6.3.1)
NOTE EMT is lighter and faster to install than threaded conduit and, with listed fittings, provides an equipment grounding path. (6.3.2)
NOTE 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, RMC or IMC is used instead. (6.3.3)
6.3.4 Electrical metallic tubing shall comply with UL 797 and the dimensional requirements of ANSI C80.3 and shall be installed per NEC Article 358.
6.3.5 EMT shall not be installed where, during installation or afterward, it is subject to severe physical damage.
6.3.6 Where EMT would be subject to severe physical damage, the Contractor shall use RMC or IMC instead.
6.3.7 EMT fittings shall be of a type listed for the location.
6.3.8 Per NEC 358.10, EMT fittings used in wet locations shall be identified for wet-location use.
6.3.9 Compression (gland) fittings, identified as raintight or concrete-tight, shall be used where the raceway is exposed to weather or embedded in concrete; set-screw fittings are permitted only in dry locations.
6.3.10 Indenter-type fittings shall not be used.
6.4.1 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.
6.4.2 A flexible whip to a recessed luminaire is limited by NEC 410.117(C) to a maximum of 6 ft, and where FMC is relied on for equipment grounding the total length in the ground-fault return path shall not exceed 6 ft.
6.4.3 Flexible metal conduit shall comply with UL 1 and shall be installed per NEC Article 348.
6.4.4 FMC shall not be used in wet locations, in concrete, or where subject to physical damage.
6.4.5 Where FMC is used as an equipment grounding path, the length and conditions shall meet NEC 348.60.
6.4.6 Where the FMC installation does not meet NEC 348.60, a separate equipment grounding conductor shall be installed in the FMC.
6.4.7 Flexible connections to vibrating or adjustable equipment shall be long enough to absorb movement and permit equipment service but no longer than necessary.
NOTE 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. (6.5.1)
6.5.2 Liquidtight flexible metal conduit shall comply with UL 360 and shall be installed per NEC Article 350.
6.5.3 LFMC shall be terminated with fittings listed for liquidtight use.
NOTE LFNC provides a flexible, corrosion-resistant, liquidtight connection where a metallic raceway is undesirable. (6.6.1)
6.6.2 Liquidtight flexible nonmetallic conduit shall comply with UL 1660 and shall be installed per NEC Article 356.
6.6.3 Because LFNC contains no metallic path, a separate equipment grounding conductor shall always be installed within it.
6.7 Rigid PVC Conduit
NOTE Rigid PVC is a nonmetallic raceway widely used for underground, direct-burial, wet-location, and corrosive-area applications. (6.7.1)
NOTE Schedule 40 PVC is the standard wall thickness. (6.7.2)
6.7.3 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 must be pulled in every PVC raceway containing circuit conductors.
NOTE PVC conduit also expands and contracts significantly with temperature change, which is addressed by the expansion-fitting requirements of this standard. (6.7.4)
● Schedule 40 (standard underground and concealed)
○ Schedule 80 (exposed to physical damage)
6.7.5 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.
6.7.6 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.
6.7.7 PVC conduit exposed to sunlight shall be listed and marked sunlight resistant.
6.7.8 A separate equipment grounding conductor sized per NEC Table 250.122 shall be installed in every rigid PVC conduit run.
6.7.9 Expansion fittings shall be provided for rigid PVC conduit as described in the expansion-fitting section of this standard.
6.7.10 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.
NOTE ENT is a flexible, corrugated, nonmetallic raceway used concealed within walls, floors, and ceilings, and within concrete. (6.8.1)
6.8.2 Electrical nonmetallic tubing shall comply with UL 1653 and shall be installed per NEC Article 362.
6.8.3 ENT shall not be installed where exposed except as permitted by NEC 362.10.
6.8.4 ENT shall not be used in plenums or environmental-air spaces unless listed for that use.
6.8.5 ENT shall not be used where ambient temperature exceeds its rating.
6.8.6 A separate equipment grounding conductor shall be installed in every ENT run.
6.9 Surface Raceway
NOTE 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. (6.9.1)
6.9.2 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.
6.9.3 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.
6.10 Wireway
NOTE 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. (6.10.1)
NEMA 1 indoor metal wireway
NEMA 3R raintight metal wireway
NEMA 4 watertight metal wireway
NEMA 12 dust-tight metal wireway
Nonmetallic wireway (corrosive locations)
6.10.2 Metal wireway and nonmetallic wireway shall comply with UL 870 and be installed per NEC Article 376 (metal) or 378 (nonmetallic).
6.10.3 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.
6.10.4 Where more than 30 current-carrying conductors are installed in a wireway, ampacity adjustment factors shall be applied.
7 Fittings, Connectors, and Couplings
NOTE Connectors and fittings maintain the mechanical integrity and, for metal raceway systems, the electrical continuity of the equipment grounding path. (7.1)
7.2 Per NEC 300.4(G), where conductors size 4 AWG and larger enter a raceway in a cabinet, box, or enclosure, the conductors must be protected from abrasion by a fitting providing a smooth, rounded insulating surface.
7.3 Per NEC 250.97, raceway terminations at equipment operating over 250V to ground, and terminations where concentric or eccentric knockouts compromise the bonding path, must be bonded around the knockout with bonding bushings, bonding locknuts, or bonding jumpers.
Set-screw (steel, dry locations)
Compression / raintight (steel, wet or exterior locations)
Threaded (RMC and IMC)
Insulated-throat with grounding lug
7.5 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.
7.6 Connectors at boxes and enclosures shall maintain the mechanical integrity and, for metal raceway systems, the electrical continuity of the equipment grounding path.
7.7 Insulating bushings or insulated throat connectors shall be provided where conductors enter a raceway termination.
7.8 Bushings shall be installed on all raceway terminations carrying conductors 4 AWG and larger.
7.9 Bonding-type fittings or bonding bushings shall be provided where required to maintain the equipment grounding path.
7.10 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.
8 Outlet, Junction, and Pull Boxes and Conduit Bodies
8.1 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.
NOTE 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; overfilled boxes overheat conductors and make device installation unreliable. (8.2)
8.3 Per NEC 314.29, boxes and conduit bodies must remain accessible without removing any part of the building or, in underground installations, without excavating paved areas.
Galvanized steel (dry interior)
Cast metal, gasketed (wet, exterior, exposed conduit systems)
Nonmetallic (corrosive locations, nonmetallic raceway systems)
Stainless steel (severe corrosive or sanitary environments)
8.4 Metallic boxes shall comply with UL 514A, nonmetallic boxes with UL 514C, and conduit bodies with UL 514B and NEMA FB 1.
8.5 Boxes and conduit bodies shall be sized, located, and supported per NEC Article 314.
8.6 Boxes installed in wet locations shall be listed for wet locations and provided with weatherproof, gasketed covers.
8.7 Outlet and device boxes shall not contain more conductors than permitted by the box fill calculation of NEC 314.16.
8.8 The Contractor shall size boxes so the calculated fill does not exceed the box volume marked by the manufacturer.
8.9 Pull and junction boxes for raceway shall be sized per NEC 314.28.
8.10 For straight pulls, the length of the box shall be at least 8 times the trade size of the largest raceway.
8.11 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.
8.12 Junction and pull boxes shall remain permanently accessible and shall not be concealed behind finished surfaces.
9 Raceway Sizing and Conductor Fill
9.1 Raceway shall be sized so that the conductors within it do not exceed the fill limits of NEC Chapter 9.
NOTE 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. (9.2)
9.3 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.
9.4 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.
NOTE Spare raceways stubbed from flush-mounted panelboards to an accessible ceiling space allow future circuits to be added without opening finished walls. (9.5)
○ No spare raceways required
● Provide spare raceways from each flush panelboard to accessible ceiling
○ Provide spare raceways as indicated on drawings
9.6 Raceway fill shall not exceed the limits of NEC Chapter 9, Table 1.
9.7 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.
9.8 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.
9.9 Where more than three current-carrying conductors occupy a raceway, ampacity adjustment factors per NEC 310.15(C)(1) shall be applied.
9.10 The Engineer shall account for this ampacity derating in feeder and branch-circuit sizing.
9.11 The Contractor shall not combine circuits into a common raceway in a manner that exceeds the design assumptions without the Engineer's approval.
10 Supports and Fasteners
10.1 Raceway shall be securely fastened in place and supported independently of other systems.
10.2 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.
10.3 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.
10.4 Threaded rod and channel strut shall be sized for the supported weight with an appropriate safety factor, and 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.
One-hole and two-hole straps to structure
Conduit clamps with beam clamps to structural steel
Trapeze hangers with threaded rod (grouped raceways)
Channel strut with conduit clamps
10.5 Raceway support spacing shall comply with the applicable NEC article for the raceway type.
10.6 EMT shall be securely fastened within 3 ft of each termination and supported at intervals not exceeding 10 ft, per NEC 358.30.
10.7 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.
10.8 Rigid PVC conduit shall be supported at the closer intervals of NEC Table 352.30.
10.9 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.
10.10 Grouped parallel raceway runs shall be supported on trapeze hangers or channel strut sized for the combined load.
10.11 Vertical raceway runs shall be secured at the top and supported at each floor or at the intervals required to prevent the weight of the raceway and conductors from bearing on fittings.
10.12 Where conductors rise vertically, conductor supports per NEC 300.19 shall be provided at the spacing required for the conductor size.
11 Expansion and Deflection Fittings
11.1 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.
NOTE Rigid PVC conduit has a coefficient of thermal expansion roughly five times that of steel, and 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. (11.2)
☑ At all building expansion and seismic joints
☐ On exposed exterior PVC runs subject to temperature swing
☐ On long exposed metal conduit runs per manufacturer guidance
☐ At transitions between structures with differential settlement
11.4 The expansion-deflection fitting at a joint crossing shall accommodate movement in the required directions.
11.5 The bonding jumper across an expansion or deflection fitting shall maintain electrical continuity of the equipment grounding path.
11.6 Per NEC 352.44, expansion fittings shall be provided for rigid PVC conduit where the expected length change due to temperature variation is 1/4 in. or more.
11.7 The Contractor shall calculate the expected length change from the installed-to-operating temperature differential and the run length.
11.8 The Contractor shall set the expansion fitting piston at installation per the manufacturer's temperature chart and locate fittings so each conduit segment can move freely.
12 Equipment Grounding and Bonding of Raceways
12.1 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. Listed RMC, IMC, and EMT with listed fittings are recognized equipment grounding conductors per NEC 250.118; nonmetallic raceways (rigid PVC, ENT, RTRC, HDPE, LFNC) provide no metallic path and require a separate equipment grounding conductor.
○ Metallic raceway as the equipment grounding conductor
● Separate equipment grounding conductor in all raceways
NOTE 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, and is preferred for feeders, for circuits serving sensitive equipment, and where the project requires the highest reliability. (12.3)
12.4 Metallic 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.
12.5 The Contractor shall verify that every coupling and connector is fully made up and that locknuts are seated through clean knockouts.
12.6 A separate equipment grounding conductor sized per NEC Table 250.122 shall be installed in every nonmetallic raceway containing circuit conductors.
12.7 A separate equipment grounding conductor shall be installed where flexible conduit is not qualified as a grounding path under NEC 250.118.
13 Installation
13.1 Raceway Routing
13.1.1 Raceway shall be routed parallel and perpendicular to building lines, concealed in finished areas, and grouped where practical for orderly installation and support.
13.1.2 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.
13.1.3 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.
13.1.5 Per NEC 300.18, raceway shall be installed complete between outlet, junction, and pull points before conductors are installed.
13.1.6 Conductors shall not be used as a means to assemble or support the raceway.
13.1.7 Open ends of raceway shall be capped or plugged during construction to keep out water, concrete, dust, and debris.
13.1.8 Raceway found with water or debris inside shall be cleaned and swabbed before conductors are installed.
13.2 Bends
13.2.1 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.
NOTE Excessive cumulative bending makes conductors impossible to pull without damaging the insulation. (13.2.2)
13.2.3 The total bend in a raceway run between pull points shall not exceed 360 degrees.
13.2.4 Where a run would require more than 360 degrees of bend, the Contractor shall install an additional pull point.
13.2.5 Bends shall be made without flattening, kinking, or reducing the internal diameter of the raceway.
13.2.6 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.
13.2.7 PVC conduit shall be bent only with equipment designed to heat the conduit uniformly; scorched or flattened PVC bends shall be rejected.
13.3 Pull Points
13.3.1 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.
13.3.2 Pull points shall be located in accessible spaces and sized per NEC 314.28.
13.4 Conductor Pulling
13.4.1 Conductors shall be pulled into raceway using a listed wire-pulling lubricant compatible with the conductor insulation and the raceway material.
13.4.2 Pulling tension and sidewall bearing pressure shall not exceed the conductor manufacturer's limits.
13.5 Sealing
13.5.1 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 must be sealed to prevent circulation of warm air to a colder section, which causes condensation inside the raceway.
13.5.2 Raceways that pass between areas of differing temperature or pressure shall be sealed to prevent the circulation of air and moisture.
13.5.3 Approved duct-sealing compound shall be installed in the raceway at the point of transition.
13.6 Firestopping
13.6.1 Where raceway penetrates a fire-rated or smoke-rated wall, floor, or ceiling, the Contractor must 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.
NOTE Firestopping coordinates with the fire-rated assembly requirements of the architectural drawings. (13.6.2)
13.6.3 Raceway penetrations of fire-rated and smoke-rated assemblies shall be sealed with a tested firestop system listed for the specific penetrant, opening size, and assembly construction.
13.6.4 The installed firestop system shall provide an F-rating and, where required, a T-rating not less than the rating of the penetrated assembly.
13.6.5 The Contractor shall maintain documentation of the firestop system used at each penetration for the project record.
14 Testing and Inspection
14.1 Raceway Proving
14.1.1 The Contractor shall verify that every underground and concealed raceway run is clear, continuous, and free of obstruction, water, and debris before pulling conductors.
● Mandrel and swab through each run
○ Mandrel, swab, and pull-string verification
14.1.2 Underground and concealed raceway shall be proved clear before conductors are installed.
14.1.3 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.
14.1.4 A raceway that does not pass the mandrel shall be excavated and corrected.
14.2 Continuity and Grounding Verification
14.2.1 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.
14.2.3 The equipment grounding path of metallic raceway systems shall be verified continuous from equipment enclosures back to the grounding electrode system.
14.2.4 Loose couplings, missing locknuts, and unbonded knockouts that interrupt the grounding path shall be corrected.
14.3 Inspection
14.3.1 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.
14.3.2 Raceway concealed without required inspection shall be uncovered at the Contractor's expense.
15 Identification and Labeling
15.1 Per NEC 314.44, the cover of each junction box, pull box, and conduit body must be marked to identify the system or circuits enclosed.
15.2 Covers for boxes serving systems other than normal power — emergency power, fire alarm, or low-voltage systems — must be marked or color-coded to distinguish them.
Permanent marker or stencil identifying the circuit
Engraved or printed adhesive label
Color-coded covers by system
Color-coded covers with engraved labels
15.3 Junction and pull box covers shall be marked to identify the systems or circuits contained, per NEC 314.44.
15.4 Covers for boxes serving systems other than normal power shall be marked or color-coded to distinguish them and shall comply with the marking requirements of the applicable NEC article for that system.
15.5 Spare and empty raceways shall be labeled at each end to indicate the origin and destination of the raceway.
15.6 Spare and empty raceways shall contain a pull string for future use.
16 Delivery, Storage, and Handling
16.1 Raceway, fittings, and boxes shall be delivered to the site in the manufacturer's original packaging with listing labels intact.
16.2 Materials shall be stored to prevent damage, corrosion, and UV degradation.
16.3 PVC conduit and nonmetallic raceway shall be stored out of direct sunlight and supported to prevent bowing and deformation.
16.4 Conduit threads and coatings shall be protected from damage; PVC-coated conduit shall be handled to avoid nicking or scraping the coating.
16.5 Damaged raceway, fittings, or coatings shall not be installed.
17 Warranty
17.1 The Contractor shall warrant the raceway installation against defects in materials and workmanship for the warranty period, beginning at substantial completion.
17.2 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.
1 year from substantial completion
2 years from substantial completion
3 years from substantial completion