DIVISION 26
RACEWAYS AND BOXES
FOR ELECTRICAL SYSTEMS
PART 1 - GENERAL
01.01 RELATED DOCUMENTS
A.
Drawings and general provisions of Contract, including General and Supplementary Conditions
and Division 1 Specification sections, apply to work of this Section.
B.
This Section is a Division 26 Basic Materials and Methods Section, and is part of each Division 26
Section making reference to electrical raceways specified herein.
01.02 DESCRIPTION OF WORK
A.
Unless specifically noted or specified otherwise, wiring shall be installed in enclosed raceway
systems. Raceways shall be sized in accordance with code for the conductors indicated. Where
space will not permit the installation of one conduit of sufficient size to contain the conductors
required, two or more conduits shall be provided. Raceway systems shall be complete with all
fittings and accessories to make the system complete. The raceway systems shall be complete
from outlet to outlet, and to cabinets and junction boxes and shall enter and be secured to boxes
and cabinets in such a manner that the system shall be electrically continuous from point of origin
to all outlets.
B.
Unless specifically noted or otherwise specified, raceways shall be installed concealed in walls
and above ceilings. Generally, raceways may be installed exposed in mechanical equipment
rooms and at ceilings of unfinished rooms.
C.
Types of raceways in this Section include the following:
Rigid nonmetallic conduit
Underground ducts
D.
Manufacturers: Firms regularly engaged in manufacture of raceway systems of types and sizes
required.
E.
NEMA Compliance: Comply with applicable requirements of NEMA standards pertaining to
raceways.
F.
Testing Laboratory Compliance and Labeling: Comply with provisions of UL or equivalent safety
standards pertaining to electrical raceway systems; and provide products and components which
have been listed and labeled by a nationally recognized testing laboratory.
G.
NEC Compliance: Comply with requirements as applicable to construction and installation of
raceway systems.
H.
Extent of electrical box and electrical fitting work is indicated by drawings and schedules.
I.
Each outlet shall be equipped with an outlet box for use with the particular raceway system being
installed in that area. Boxes shall be of the knockout or threaded hub type, not less than 4" size.
J.
In cases where outlet boxes are to be installed in walls made of glazed tile, brick or other masonry
which will not be covered with plaster or other finish; and where wood or other types of paneling
will be installed; boxes shall be 4" square size having a one or two device raised cover. Extension
in cover shall not be less than 1" and raised portion of cover shall have straight sides. Where
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DIVISION 26
RACEWAYS AND BOXES
FOR ELECTRICAL SYSTEMS
more than two gangs are required or where thickness of masonry will not allow the use of a 4" box
with 1" raised cover, 3¾" long masonry boxes shall be used.
K.
Sectional switch boxes and die cast boxes are not approved and shall not be used.
L.
Where special equipment or devices are to be installed in outlet boxes, the Electrical Contractor
shall obtain information from manufacturers of such equipment or devices to determine size box
required.
M.
Straight through boxes are not to be used. Boxes shall not be installed back to back, unless
otherwise noted.
N.
Outlet boxes for communications outlets shall be 4" square with single gang mud ring and with a
plate of same design and finish of device plates.
O.
Outlet boxes shall be selected to suit the device to be installed. All plates shall be of same design
and finish as device plates. Where outlets are provided for the future installation of equipment,
unless otherwise noted, provide a 4" square box with one or two gang, cover and blank plate.
P.
Conduit bodies shall be malleable cast iron, copper free aluminum or PVC to suit conduit system.
Conduit bodies shall not be used for conduits larger than 1½".
Q.
Box material shall be as follows:
Raceway System
PVC
Installation Method
Concealed
Exposed
PVC
PVC
Steel boxes shall be galvanized. Cast iron shall be malleable.
01.03 QUALITY ASSURANCE
A.
Manufacturers: Firms regularly engaged in manufacture of electrical boxes and fittings, of types
and sizes required, whose products have been in satisfactory use in similar service.
B.
NEC Compliance: Comply with NEC Article 314 as applicable to construction and installation of
electrical wiring boxes and fittings.
C.
Testing Laboratory Compliance: Provide electrical boxes and fittings which have been listed and
labeled by a nationally recognized testing laboratory.
D.
ANSI/NEMA Standards Compliance: Comply with ANSI C 134.1 (NEMA Standards Pub
No. OS 1) as applicable to sheet-steel outlet boxes, device boxes, covers and box supports.
01.04 SHOP DRAWINGS
A.
Shop drawing submittals are not required for conduit, wireways, auxiliary gutters, boxes and
fittings. Submit Shop Drawings consisting of manufacturer’s product data on surface metal
raceway systems.
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DIVISION 26
RACEWAYS AND BOXES
FOR ELECTRICAL SYSTEMS
PART 2 - PRODUCTS
02.01 RIGID NONMETALLIC CONDUIT (TYPE RNC)
A.
Poly Vinyl Chloride Conduit (PVC) shall be heavy wall UL Type 40. Conduit shall be Carlon PV
DUIT 40 Plus, 90 C, UL rated or approved equal. Material shall comply to NEMA Specification
TC-2 (Conduit), TC-3 (Fittings-UL-514), Federal Specification W-C-1094A and UL-651 (Standard
for rigid non-metallic conduit) and ANSI C33.91 and comply with requirements of NEC Article 352.
B.
The conduit shall be made from virgin polyvinyl chloride C-300 compound which includes inert
modifiers to improve weatherability, heat distortion and offer reduced smoke and HCL emissions
in fire conditions. Clean rework material, generated by the manufacturer's own conduit
production, may be used by the same manufacturer, provided the end products meet the
requirements of this Specification.
C.
Conduit and fittings shall be solvent welded in applications in accordance with instructions from
the manufacturer.
D.
A ground conductor shall be installed in PVC raceways unless specifically noted otherwise.
E.
All elbows in PVC raceways shall be PVC coated steel.
02.02 UNDERGROUND DUCTS
A.
Underground ducts shall consist of one or more raceways encased in concrete, buried
underground.
B.
Dimensions of duct bank, spacing of raceways, etc., shall be as detailed on drawings.
C.
Concrete shall be placed in two pours. Raceways shall be arranged in place and anchored
securely on top of first pour.
D.
Where multiple raceways are to be provided, separation shall be fixed by installation of plastic
spacers located at 5'-0", or closer, intervals along run.
E.
Steel reinforcing shall be provided as detailed.
F.
Raceways installed in concrete encased duct bank shall be plastic PVC Schedule 40 or rigid
metal.
02.03 BOXES – FABRICATED MATERIALS
A.
Interior Outlet Boxes: Provide interior outlet wiring boxes, of types, shapes, and sizes, including
box depths, to suit each raceway system and respective location and installation; construct with
stamped knockouts or with threaded hubs in back and sides, and with threaded screw holes with
corrosion-resistant screws for securing box covers and wiring devices.
1.
Section 26 05 33
Interior Outlet Box Accessories: Provide outlet box accessories as required for each
installation, including mounting brackets, wallboard hangers, extension, rings, fixture
studs and metal straps for supporting outlet boxes, which are compatible with outlet
boxes being used and fulfilling requirements of individual wiring situations. Choice of
accessories is Installer's option.
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DIVISION 26
RACEWAYS AND BOXES
FOR ELECTRICAL SYSTEMS
B.
Weatherproof Outlet Boxes: Provide corrosion-resistant castmetal weatherproof outlet wiring
boxes, of types, shapes and sizes, including depth of boxes, with threaded conduit ends,
cast-metal face plates with spring-hinged waterproof caps suitably configured for each application,
including face plate gaskets and corrosion-resistant fasteners.
C.
Junction and Pull Boxes: Provide galvanized code-gauge sheet steel junction and pull boxes, with
screw-on covers; of types, shapes and sizes, to suit each respective location and installation; with
welded seams and equipped with stainless steel nuts, bolts, screws and washers.
D.
Air-Vapor Barrier Boxes: Provide a Lessco air-vapor barrier box for each outlet box, device box,
or light fixture box installed in an exterior wall or gypsum board ceiling.
E.
Conduit Bodies: Provide conduit bodies, of types, shapes, and sizes, to suit raceway system and
respective locations and installation. Construct with threaded-conduit-entrance ends, removable
covers, and corrosion-resistant screws.
F.
Bushings, Knockout Closures and Locknuts: Provide corrosion resistant punched-steel box
knockout closures, conduit locknuts and malleable iron conduit bushings, offset connectors, of
types and sizes to suit respective uses and installation.
G.
Boxes for installation in concrete or masonry shall be identified as suitably protected from
corrosion and shall be constructed to prevent ingress of concrete during pour.
PART 3 - EXECUTION
03.01 INSTALLATION OF ELECTRICAL RACEWAYS
A.
Locations for the several raceway types described above shall be as follows:
1.
PVC conduit is to be used:
Exterior: In concrete encasement
Where buried underground, PVC conduit shall be buried not less than 24” below grade.
Before PVC conduit emerges from floor or from ground a change shall be made to rigid
metal raceway beginning at the elbow. PVC conduit shall not be exposed.
When terminating PVC conduit, threaded fittings shall not be used. Connections shall be
made with a coupling and bushing type box adapter, or to integral hub on box or fitting.
Connections shall be solvent welded.
2.
B.
Underground ducts are to be provided where indicated on drawings or where specifically
stated in Specifications.
Raceways crossing building expansion joints shall be approved steel expansion fittings allowing
for building contraction, expansion and settlement. Crossing of expansion joints in building
construction shall be avoided where possible. Refer to Architectural and Structural drawings for
locations of expansion joints.
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DIVISION 26
RACEWAYS AND BOXES
FOR ELECTRICAL SYSTEMS
C.
Exposed raceways shall be installed in a mechanical and workmanlike manner and shall be rigidly
supported by means of pipe hangers or straps. Exposed runs shall parallel the building
construction. Bends in exposed raceways shall be right angle.
D.
Horizontal conduits shall typically be supported within 3 feet of each outlet box, junction box,
cabinet, conduit body or other conduit termination and at intervals thereafter not exceeding 10
feet. Comply with all requirements in the respective NEC Articles. Supports shall be conduit
straps or hangers. Perforated strap and/or iron wire is not approved and shall not be used.
E.
Pullboxes shall be installed in raceway runs when necessary to facilitate the pulling of wires.
Pullboxes shall be located so as to be accessible after the building is completed. Pullboxes shall
not be placed in finished spaces without special permission.
F.
It shall be the responsibility of this contractor to consult with the Mechanical Contractors before
installing conduit or pullboxes for electrical feeders in order that any conflicts between the
locations of raceway runs, piping and ductwork shall be avoided. Such locations shall be
approved by the Engineer and shall in no case result in additional cost to the Owner.
G.
Raceways are not to be mounted on equipment except where necessary to make connections to
electrical devices which is part of or mounted on such equipment. Where raceways must be run
on equipment, care shall be taken not to cover access doors, controls, removable panels, etc., or
otherwise hinder the normal maintenance and repair of the equipment.
H.
Complete installation of electrical raceways before starting installation of cables/wires within
raceways.
I.
Wherever possible, install horizontal raceway runs above water piping.
J.
Upon completion of installation of raceways, inspect interiors of raceways; remove burrs, dirt and
construction debris.
K.
Raceways shall be installed in accord with the NECA Standard of Installation.
L.
Conduit joints shall be cut square, threaded, reamed smooth and drawn up tight. Bends or offsets
shall be made with standard ells, field bends made with an approved bender or hickey, or hub
type, conduit bodies. Conduit ends shall be capped during construction. Conduits shall be
terminated at cabinets and boxes with locknuts and bushings. On conduits 1" and larger
insulating bushings shall be installed.
M.
Fittings for flexible conduit shall be malleable steel.
N.
Empty steel conduit shown for future wiring shall have nylon pull wire. Empty PVC conduit shall
have No. 16 galvanized pull wire.
O.
Raceways and underground ducts installed underground shall be installed in trenches. Trenching
and backfilling shall be as described in Section 26 05 75 “Electrical Related Work”.
P.
Where continuous conduit systems pass through tunnel walls and/or exterior walls below grade,
the entrance shall be made watertight by the use of OZ/Gedney conduit seal bushings. All
underground conduit penetrating the building exterior walls below grade shall slope away from the
building without exception.
Q.
Minimum conduit size shall be 3/4".
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DIVISION 26
RACEWAYS AND BOXES
FOR ELECTRICAL SYSTEMS
R.
All underground conduit shall be installed to drain into handholes. Minimum cover requirements
for underground conduit shall be as required in NEC Table 300.5 or as noted on drawings.
S.
Where underground conduit must run under walkways, driving surfaces, or other paved areas,
install a 2" or larger rigid metal sleeve around the conduit.
T.
Provide sealing of conduits where conduits pass from areas of different temperatures to prevent
circulation of warm air to a colder section of raceway that could cause condensation. Comply with
NEC Article 300.7.
03.02 INSTALLATION OF ELECTRICAL BOXES AND FITTINGS
A.
General: Install electrical boxes and fittings where indicated, complying with manufacturer's
written instructions, applicable requirements of NEC and NECA's "Standard of Installation", and in
compliance with recognized industry practices to ensure that products fulfill requirements.
B.
Pullboxes shall be installed in raceway runs when necessary to facilitate the pulling of wires.
Pullboxes shall be located so as to be accessible after the building is completed. Pullboxes shall
not be placed in finished spaces without special permission.
C.
Coordinate installation of electrical boxes and fittings with wire/cable and raceway installation
work.
D.
Provide weatherproof outlets for interior and exterior locations exposed to weather or moisture.
E.
Provide knockout closures to cap unused knockout holes where blanks have been removed.
F.
Install boxes and conduit bodies in those locations to ensure ready accessibility of electrical
wiring.
G.
Provide electrical connections for installed boxes.
END OF SECTION 26 05 33
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