SECTION 26 05 33 Raceway and Boxes For Electrical Systems
SECTION 26 05 33 Raceway and Boxes For Electrical Systems
SECTION 26 05 33 Raceway and Boxes For Electrical Systems
SECTION 26 05 33
RACEWAY AND BOXES FOR ELECTRICAL SYSTEMS
PART 2 - PRODUCTS
2.1 MATERIAL
SPEC WRITER NOTES: Coordinate with Section
26 05 21, LOW-VOLTAGE ELECTRICAL POWER AND
CONDUCTORS to insure that type THW
insulation is not specified for use in 13
mm (1/2 inch) conduit.
A. Conduit Size: In accordance with the NEC, but not less than 13 mm
(1/2 inch) unless otherwise shown. Where permitted by the NEC, 13 mm
(1/2 inch) flexible conduit may be used for tap connections to recessed
lighting fixtures.
B. Conduit:
1. Rigid galvanized steel: Shall Conform to UL 6, ANSI C80.1.
2. Rigid aluminum: Shall Conform to UL 6A, ANSI C80.5.
3. Rigid intermediate steel conduit (IMC): Shall Conform to UL 1242,
ANSI C80.6.
4. Electrical metallic tubing (EMT): Shall Conform to UL 797, ANSI
C80.3. Maximum size not to exceed 105 mm (4 inch) and shall be
permitted only with cable rated 600 volts or less.
5. Flexible galvanized steel conduit: Shall Conform to UL 1.
6. Liquid-tight flexible metal conduit: Shall Conform to UL 360.
7. Direct burial plastic conduit: Shall conform to UL 651 and UL 651A,
heavy wall PVC or high density polyethylene (PE).
8. Surface metal raceway: Shall Conform to UL 5.
C. Conduit Fittings:
1. Rigid steel and IMC conduit fittings:
a. Fittings shall meet the requirements of UL 514B and ANSI/ NEMA
FB1.
b. Standard threaded couplings, locknuts, bushings, and elbows: Only
steel or malleable iron materials are acceptable. Integral
retractable type IMC couplings are also acceptable.
c. Locknuts: Bonding type with sharp edges for digging into the metal
wall of an enclosure.
d. Bushings: Metallic insulating type, consisting of an insulating
insert molded or locked into the metallic body of the fitting.
Bushings made entirely of metal or nonmetallic material are not
permitted.
2. Cast metal where required by the NEC or shown, and equipped with
rustproof boxes.
3. Sheet metal boxes: Galvanized steel, except where otherwise shown.
4. Flush mounted wall or ceiling boxes shall be installed with raised
covers so that front face of raised cover is flush with the wall.
Surface mounted wall or ceiling boxes shall be installed with surface
style flat or raised covers.
F. Wireways: Equip with hinged covers, except where removable covers are
shown.
SPEC WRITER NOTES: Use non-detectable type
for cemetery projects only.
b. Not less than 750 mm (30 inches) below road and other paved
surfaces.
//c. Installation under railroad tracks is prohibited.//
5. Work with extreme care near existing ducts, conduits, cables, and
other utilities to avoid damaging them.
6. Excavation for conduit bedding and back-filling of trenches is
specified in Section 31 20 00, EARTH MOVING.
a. Cut the trenches neatly and uniformly.
b. Do not kink the conduits.
7. Seal conduits, including spare conduits, at building entrances and at
outdoor terminations for equipment with a suitable compound that
prevents the entrance of moisture and gases.
8. Where metal conduit is shown, install threaded heavy wall rigid steel
galvanized conduit or type A20 rigid steel galvanized conduit coated
with .5 mm (20 mil) bonded PVC, or rigid steel or IMC, PVC coated or
standard coated with bituminous asphaltic compound.
9. Warning tape shall be continuously placed 300 mm (12 inches) above
conduits or electric lines.
B. Exterior routing of lighting systems and other branch circuits (600
volts and less-under buildings slab on grade to 1500 mm (5 feet) from
the building):
1. Pre-coated rigid galvanized steel conduit in accordance with the
requirements of Section 26 05 41, UNDERGROUND ELECTRICAL
CONSTRUCTION.
3.6 HAZARDOUS LOCATIONS
A. Use rigid steel conduit only, notwithstanding requirements otherwise
specified in this or other sections of these specifications.
B. Install UL approved sealing fittings, that prevent passage of explosive
vapors, in hazardous areas equipped with explosive proof lighting
fixtures, switches, and receptacles, as required by the NEC.
3.7 WET OR DAMP LOCATIONS
A. Unless otherwise shown, use conduits of rigid steel or IMC.
B. Provide sealing fittings, to prevent passage of water vapor, where
conduits pass from warm to cold locations, i.e., (refrigerated spaces,
constant temperature rooms, air conditioned spaces building exterior
walls, roofs) or similar spaces.
C. Unless otherwise shown, use rigid steel or IMC conduit within 1500 mm (5
feet) of the exterior and below concrete building slabs in contact with
soil, gravel, or vapor barriers. Conduit shall include an outer factory
coating of .5 mm (20 mil) bonded PVC or field coat with asphaltum before
installation. After installation, completely coat damaged areas of
coating.
3.8 MOTORS AND VIBRATING EQUIPMENT
A. Use flexible metal conduit for connections to motors and other
electrical equipment subject to movement, vibration, misalignment,
cramped quarters, or noise transmission.
B. Provide liquid-tight flexible metal conduit for installation in exterior
locations, moisture or humidity laden atmosphere, corrosive atmosphere,
water or spray wash-down operations, inside (air stream) of HVAC units,
and locations subject to seepage or dripping of oil, grease or water.
Provide a green ground wire with flexible metal conduit.
3.9 EXPANSION JOINTS
A. Conduits 75 mm (3 inches) and larger, that are secured to the building
structure on opposite sides of a building expansion joint, require
expansion and deflection couplings. Install the couplings in accordance
with the manufacturer's recommendations.
B. Provide conduits smaller than 75 mm (3 inches) with junction boxes on
both sides of the expansion joint. Connect conduits to junction boxes
with sufficient slack of flexible conduit to produce 125 mm (5 inch)
vertical drop midway between the ends. Flexible conduit shall have a
copper green ground bonding jumper installed. In lieu of this flexible
conduit, expansion and deflection couplings as specified above for 375
mm (15 inches) and larger conduits are acceptable.
C. Install expansion and deflection couplings where shown.
SPEC WRITER NOTES: Include the following
paragraph for seismic areas only.