General Construction Specifications
PART 1 - GENERAL
01 WORK INCLUDED
A. Rigid steel conduit and fittings.
B. Intermediate metal conduit and fittings.
C. Liquidtight flexible metal conduit and fittings.
D. Non-metallic conduit and fittings.
E. Non-metallic coated rigid metal conduit and fittings.
02 REFERENCES
A. ANSI C80.1 - Rigid Steel Conduit, Zinc-Coated.
B. ANSI C80.3 - Electrical Metallic Tubing.
C. ANSI C80.6 - Intermediate Metal Conduit.
D. ANSI/NEMA FB 1 - Fittings and Supports for Conduit and Cable Assemblies.
E. NEMA TC 3 - PVC Fittings for Use with Rigid PVC Conduit and Tubing.
F. UL Standard 886 - Fittings for Use in Hazardous Locations.
G. ANSI C80.5 - Aluminum Electrical Metallic Tubing.
H. NEMA RNI - Plastic Coated Rigid Steel Conduit.
PART 2 - PRODUCTS
03 RIGID METAL CONDUIT AND FITTINGS
A. Rigid Steel Conduit: ANSI C80.1.
B. Fittings and Conduit Bodies: ANSI/NEMA FB 1; threaded type, galvanized steel.
C. Explosion-proof Fittings: UL Standard 886.
04 INTERMEDIATE METAL CONDUIT (IMC) AND FITTINGS
A. Conduit: Galvanized steel, ANSI C80.6.
B. Fittings and Conduit Bodies: ANSI/NEMA FB 1; use fittings and conduit bodies specified above for rigid steel conduit.
C. Explosion-proof Fittings: UL Standard 886.
05 LIQUIDTIGHT FLEXIBLE CONDUIT AND FITTINGS
A. Conduit: Flexible metal conduit with PVC jacket.
B. Fittings and Conduit Bodies: ANSI/NEMA FB 1.
06 PLASTIC CONDUIT AND FITTINGS
A. Conduit: NEMA TC 2; Schedule 40 PVC.
B. Fittings and Conduit Bodies: NEMA TC 3. Use solvent cement type.
07 PLASTIC COATED RIGID STEEL CONDUIT
A. Conduit: NEMA Standard RNI, Type A20 with 15 mils minimum coating of polyvinyl chloride (PVC).
B. Fittings and Conduit Bodies: ANSI/NEMA threaded type, PVC coated galvanized steel.
08 CONDUIT SUPPORTS
A. Conduit Clamps, Straps, and Supports: Galvanized steel.
B. Caddy clips.
09 FIRE STOPS
A. Mechanical fire-stop fittings shall be manufactured by Crouse Hinds, O-Z/Gedney or Square D.
B. Foam sealing compounds shall be silicone type, Chase Technology PR-855, Dow Corning "Fire Stop" or General Electric Pensil 851.
C. Conduit connections shall be made with appropriate fittings and securely tightened. Improperly made connections or terminations, as well as any not adequately tightened, will be rejected.
PART 3 - EXECUTION
010 CONDUIT SIZING, ARRANGEMENT, AND SUPPORT
A. Interior conduits shall be 1/2" minimum size. Exterior conduits shall be 1" minimum size.
B. Arrange conduit to maintain headroom and present a neat appearance.
C. Route exposed conduit tight to structure parallel and perpendicular to walls and adjacent piping.
1. Group Supports:
a) Conduits running vertically. Fasten mounting channels to hollow masonry with toggle bolts.
b) Conduits running horizontally. Suspend trapeze hangers with 3/8 inch rods connected to bar joints.
c) Hanger and Supports - Single Runs:
d) Fasten 1-1/4 inch and smaller on walls using one-hole straps with screws and suitable anchors.
e) Fasten 1-1/4 inch and smaller on bar joists using one-hole straps with bolts.
f) Fasten 1-1/2 inch and larger on walls using two-hole straps with screws and suitable anchors.
g) Fasten 1-1/2 inch and larger on bar joists using two-hole straps with bolts.
h) Hang from structure using 3/8 inch rod hangers, suitable anchors, and band hangers.
B. Maintain minimum 6 inch clearance between conduit and piping. Maintain 12 inch clearance between conduit and heat sources such as flues, and heating appliances.
C. Arrange conduit supports to prevent distortion of alignment by wire pulling operations. Fasten conduit using galvanized straps, clevis hangers, or unistrut. Supports shall be spaced to meet or exceed minimum National Electrical Code requirements.
D. Group conduit in parallel runs where practical and use conduit rack constructed of steel channel with conduit straps or clamps. Provide space for 25 percent additional conduit.
E. Do not fasten conduit with tee wire, plastic ties, or perforated pipe straps. Remove all wire used for temporary conduit support during construction, before conductors are pulled.
F. Do not support conduits from any other piping, accessible ceiling support wires, or ductwork. All conduit shall be supported directly to the structure.
3.02 CONDUIT INSTALLATION SCHEDULE
A. Refer to National Electrical Code, Article 100, for the definition of Service Entrance, Feeder, and Branch Circuits.
B. Service Entrance and Exterior Feeders Underground: Use Schedule 40 plastic encased in concrete duct bank. Concrete duct bank may be deleted underneath building slab.
C. Interior Feeders: Use rigid steel or intermediate metal conduit. Schedule 40 PVC may be used in or under slabs on grade when covered by a minimum of 4" of concrete.
D. Interior Branch Circuits: Use rigid steel or intermediate metal conduit unless otherwise noted. Schedule 40 PVC may be used in slabs on grade when covered by a minimum of 4" of concrete.
E. Exterior Branch Circuits Underground: Use rigid steel, intermediate metal or Schedule 40 plastic conduit. Install a minimum of 24" below grade.
F. Exterior Feeders and Branch Circuits Exposed Exterior or in Wet Interior Locations: Use rigid steel or intermediate metal conduit unless otherwise noted.
Use flexible liquid-tight conduit for motor transformer final connections and to other devices subject to vibration.
G. Systems Conduits: Where conduits are required by Contract Documents, use same materials as branch circuits conduits for the conditions itemized above.
H. All conduit installed in hazardous locations as defined in Article 500 of the National Electrical Code: Rigid steel or intermediate metal conduit.
I. Service entrance conductors shall be encased in concrete up to the enclosure of the disconnecting means.
3.03 CONDUIT INSTALLATION
A. Cut conduit square using a saw or pipecutter; de-burr cut ends.
B. Bring conduit to the shoulder of fittings and couplings and fasten securely.
C. Use conduit hubs for fastening conduit to cast boxes and for fastening conduit to metal boxes in damp or wet locations.
D. There shall not be more than the equivalent of four 90-degree bends between pull points; e.g., conduit bodies and boxes. Provide pull or junction boxes in conduit runs, spaced a maximum of 100 feet between boxes.
E. Use conduit bodies to make sharp changes in direction, as around beams.
F. Use hydraulic one-shot conduit bender or factory elbows for bends in conduit larger than 2 inch size.
G. Avoid moisture traps where possible; where unavoidable, provide junction box with drain fitting at conduit low point.
H. Use suitable conduit caps to protect installed conduit against entrance of dirt and moisture. Remove all water and debris from conduits before installing wire. Tape shall not be an acceptable method of protection.
I. Provide a 200 lb. minimum test nylon pull string in empty conduit, except sleeves and nipples.
J. Install expansion joints where conduit crosses building expansion joints. Provide expansion joint with bonding wire.
K. Where conduit penetrates fire-rated walls and floors, seal opening around conduit with foamed sealing compound or provide mechanical fire-stop fittings with UL listed fire rating equal to wall or floor rating.
L. Route conduit through roof openings for piping and ductwork where possible; otherwise, route through roof jack with pitch pocket.
M. Where plastic conduits are allowed, use galvanized rigid steel conduit or intermediate metal conduit factory elbows to turn plastic conduits up above grade or slab.
N. Provide 4 inches minimum coverage of concrete over top and on sides of conduits installed in slabs on grade.
O. Terminate service entrance conduits with compound filled bushings. Bond metal conduits to service entrance ground bus with a separate jumper for each conduit.
P. Where conduits are stubbed off without terminating in a cabinet, junction box, etc. (such as at telephone terminal boards, conduits stubbed out of walls above accessible ceilings, etc), terminate the conduit with a nylon bushing.
Q. Wipe plastic conduit clean and dry before joining. Apply full even coat of cement to entire area that will be inserted into fitting. Let joint cure for 20 minutes minimum.
R. Install conduits in hazardous locations in accordance with Article 500 of the National Electrical Code and other applicable Articles. Provide malleable iron, compound filled explosion proof sealing fittings where conduits leave hazardous locations and elsewhere as required.
S. Provide double locknuts on all feeder conduits.
T. Provide plastic bushings or insulated throats for all conduit terminations in boxes, panelboards, cabinets, etc.
U. Provide a minimum of 12 inches of liquid-tight flexible conduit above a pitch pocket to minimize vibration.
V. Rigid steel conduit or intermediate conduit installed underground shall be coated with two coats of asphaltum. PVC coated rigid steel may be used in lieu of this.
W. Conduits crushed or deformed in bending shall be rejected. Where a number of conduits are run together, the radii of any required bend shall be such that the installation will be neat in appearance.
X. Rigid steel conduit and intermediate metallic conduit shall be supported in accordance with N.E.C. Articles 346-12 and 348-12 respectively. Vertical runs of all conduits shall be supported in accordance with N.E.C. Article 300-19.
Y. In general, conduit layout on the drawings is diagrammatic. Follow layout where possible, but where changes are necessary due to structural conditions, other apparatus, or other causes, make them. Offsets in conduits are not indicated; furnish as required.
3.04 UNDERGROUND DUCTBANK INSTALLATION
A. Install top of duct bank minimum 36 inches below finished grade.
B. Stagger conduit joints in concrete encasement 6 inches minimum vertically and horizontally.
C. Use suitable separators and chairs installed not greater than 8 feet on centers. Band conduit together with suitable banding devices. Securely anchor conduit to prevent movement during concrete placement.
D. Provide minimum 3 inch concrete cover at bottom, top, and sides of duct bank. Also provide a minimum of 3 inch concrete between conduit.
E. Provide red dyed concrete for duct banks.
F. Provide 4000 psi concrete for duct banks.
G. Provide two No. 4 steel reinforcing bars in top of bank under paved areas.
H. Provide dated pictures showing compliance with Items B, C, and D above.
I. Provide warning tape approved by the power company 12 inches above the top of the duct bank for all primary duct banks.
END OF SECTION
