1、Standard for InstallingNonmetallic Raceways (RNC, ENT, LFNC)NECA 111-2003AMERICAN NATIONAL STANDARDNational ElectricalContractors Association3 Bethesda Metro CenterSuite 1100 Bethesda, MD 20814301-657-3110 fax: 301-215-4500www.neca-neis.orgStandards cement will absorb mois-ture from the air.b) Follo
2、w manufacturer recommendations forselecting suitable solvent cement for the installationrequirements. Match temperature rating of cementto installation conditions.NOTE: Three types of cement are available for RNC,based on the viscosity: regular bodied, medium bodied,and heavy bodied. Regular bodied
3、cement is suitablefor most raceway applications up through 6 inches. Forbetter gap filling needs, a medium bodied cementshould be selected. For raceways, where a watertightjoint is needed, or for extremely hot weather use, selecta heavy bodied cement. For cement joints in corrugat-ed ENT, use manufa
4、cturer recommended ENT solventcement. Do not use PVC solvent cement on the threadsof threaded fittings.c) Wipe joint surfaces clean of dirt or moisture orother contaminants. Clean dirty or oil-coated race-way joining surfaces using PVC cleaner or primer inaccordance with manufacturer recommendations
5、.Thoroughly dry raceway joining surfaces. NOTE: Donot attempt to join raceways when any indication ofmoisture is present.d) Cool joint areas of raceways that are 90F orabove by shading or by applying a damp cloth.NOTE: Thoroughly dry raceways when using a dampcloth to cool raceways. Allow area to dr
6、y before apply-ing cement.NOTE: Hot raceway surfaces cause rapid drying of thecement, resulting in insufficient welding. Verify thatcement is liquid on raceway surfaces when joining thespigot and bell or fitting. Using a heavier, slower dry-ing cement may be appropriate when it is impracticalto cool
7、 the joints.e) Apply a full, even coat of cement to the entire areaof the spigot that will be inserted into the bell or fit-ting. Use the dauber applicator supplied in the lid ofthe cement container. Apply the cement quickly andevenly around the spigot and insert into the bell orfitting while the ce
8、ment is still liquid.f) Insert the spigot fully into the bell or fitting, twist-ing the spigot section one-quarter turn as insertion ismade. Hold the joint firmly together for 10 to 20seconds without movement. (NOTE: Cold weatherapplications may require a longer holding time.) If thespigot section b
9、acks out upon release, pull the jointapart, apply another coat of cement, and reassembleand hold until the joint does not back out uponrelease.NOTE: A small bead of cement should appear aroundthe lip of the bell or fitting if adequate cement has beenapplied. Wipe off excess bead after joint has set.
10、g) Carefully handle newly assembled joints until thecement has cured. If manufacturers recommenda-tions are unavailable, use minimum recommendedcuring times found in Table 4.9 Minimum CementCuring Time.4.9.1 Solvent Welding Fittings to ENTa) Use solvent cement or other PVC cement whichis specificall
11、y labeled for use with ENT.NOTE: Do not use heavy- or medium-bodied PVCcement or combinations of ABS and PVC cement.b) Remove all dust, dirt and moisture from ENT andfittings before applying cement. NOTE: Do not useprimer or cleaner.c) Apply solvent cement with the natural bristlebrush supplied in t
12、he can lid. NOTE: Do not use adauber.d) Apply a light, uniform coat of cement inside thesocket fitting. Apply a light, uniform coat of cementto the outside surface of the ENT to the depth of theNECA 111 Standard for Installing Nonmetallic Raceways (RNC, ENT, LFNC)a73 10Table 4.9 Minimum Cement Curin
13、g TimeTemperature TimeRange60 to 100F (15 to 40C) 30 minutes40 to 60F (5 to 15C) 1 hour20 to 40F (-5 to 5C) 2 hours0 to 20F (-20 to -5C) 4 hoursNote: Joint damage or loosening may occur up to48 hours after assembly in temperatures below40F, if the joints are severely stressed.fitting socket. Brush a
14、round the corrugations of theENT. NOTE: Do not brush longitudinally along theENT.e) Brush away any excess cement out of the groovesof the ENT.NOTE: Excess cement may cause burning and excesssoftening of the ENT which may result in joint failureunder stress.f) Quickly insert tubing into fitting while
15、 cement isstill wet up to the center stop of the fitting. Give thefitting a quarter turn and hold firmly in place for 15to 30 seconds. Do not disturb the fitting for two tofive minutes to allow firm joint set.4.10 Raceways Concealed in Masonry andConcretea) Tie raceway to reinforcing rods or support
16、 to pre-vent movement such as floating or sagging whenconcrete is placed. Locate spacers, if used, at inter-vals not exceeding the maximum spacing indicated inTable 4.10 Maximum Spacer Intervals.b) Rising temperature from curing concrete cancause expansion of the raceway. Pour concrete fromthe cente
17、r of the raceway run toward each free end orfrom one tie-in point toward the free end of the race-way. Make permanent terminal tie-ins after the tem-perature has normalized.c) Locate raceways in the middle third of cast-in-place slabs and walls and leave at least 1 inch con-crete cover. Place racewa
18、ys between bottom reinforc-ing steel and top reinforcing steel and run either par-allel or perpendicular to main reinforcing steel.When at right angles to reinforcement, place racewayclose to slab support.d) Provide a lateral separation of raceways not lessthan three raceway diameters except where t
19、hearrangement is approved or where contract docu-ments indicate that the concrete slab has been espe-cially designed to accommodate a closer spacing,such as where raceways enter wire closets, panel-boards, or electrical boxes.e) Transition from ENT to RNC before rising abovefloor. ENT and LFNC may b
20、e used for final equip-ment connections 6 inches or more above the floor.f) Do not install raceways in slabs or walls when theoutside raceway diameter exceeds 1/3 of the slab orwall thickness. Do not install raceways in a slab top-ping of two inches or less. Do not route raceways tocross each other
21、in slabs above grade.4.11 Sealsa) Use manufacturer recommended watertight andsmoketight wall and floor seals, of types and sizesrequired suitable for sealing around raceway, pipe, ortubing passing through concrete floors and walls, andwhere raceways pass between areas of differing tem-peratures such
22、 as into or out of cool rooms, freezers,unheated and heated spaces, buildings, etc.b) Seal penetrations in floors, walls or other generalconstruction with a listed, 3 hour-rated smoke andfirestopping sealant.c) Close floor slots and openings with 16 gauge gal-vanized steel sheet supported on 1 inch
23、by 1 inch by1/8 inch structural angle drilled or supported withpowerdriven studs into the building structure.Firestop with a minimum 1-inch thick layer of sili-cone elastomer, with the top surface of the siliconeelastomer approximately 1 inch below the finishedfloor slab surface.d) Close openings in
24、 walls with 16 gauge galvanizedsteel sheet securely attached at the midpoint of theInstallation 11 a73Table 4.10 Maximum Spacer IntervalsRaceway Size Maximum Spacing(feet)1/2 - 2 4 - 62-1/2 - 3-1/2 5 - 84 - 6 6 - 10wall thickness and firestopped on both sides of thesteel sheet with a minimum of 1/2
25、inch thick layer ofnonsagging silicone elastomer that completely coversthe opening.e) Tighten sleeve seal screws until grommets haveexpanded to form watertight and smoketight seal.4.12 Cleaninga) Upon completion of installation of raceway sys-tems, inspect interiors of raceways at all outlet, junc-t
26、ion and pull boxes. Remove burrs, dirt, and con-struction debris. Repair damaged finish, includingchips, scratches, and abrasions.b) Run a swab or mandrel through raceways toremove dirt and blockages. Replace raceways whichare deformed and prevent the passage of a mandrel.c) Use suitable temporary c
27、losure protection to pre-vent further contamination from construction debris,foreign materials, dirt, moisture, plaster. Provideknockout closures to cap unused knockout holeswhere blanks have been removed. Protect stubupsfrom physical damage during construction whereraceways rise from floor slabs.d)
28、 Label and identify raceways in accordance withcontract documents. Install electrical identificationprior to installation of acoustical ceilings and similarfinishes that conceal raceways.NECA 600 Recommended Practice for Installing and Maintaining Medium-Voltage Cablea73 12This publication, when use
29、d in conjunction with the National Electrical Code and product manufacturers lit-erature, provides sufficient information to install nonmetallic raceways. The following publications may alsoprovide useful information:National Fire Protection Association1 Batterymarch ParkP.O. Box 9101Quincy, Massach
30、usetts 02269-9101(617) 770-3000 tel(617) 770-3500 faxwww.nfpa.orgNFPA 70-2002, National Electrical Code (ANSI)Current National Electrical Installation Standardspublished by NECA:NECA 1-2000, Standard Practices for Good Workmanship in Electrical Contracting (ANSI)NECA 100-1999, Symbols for Electrical
31、 Construction Drawings (ANSI)NECA 101-2001, Standard for Installing Steel Conduits (Rigid, IMC, EMT)NECA/AA 104-2000, Recommended Practice for Installing Aluminum Building Wire and Cable (ANSI)NECA/NEMA 105-2002, Recommended Practice for Installing Metal Cable Tray Systems (ANSI)NECA 111-2003, Stand
32、ard for Installing Nonmetallic Raceways (RNC, ENT, LFNC) (ANSI)NECA 200-2002, Recommended Practice for Installing and Maintaining Temporary Electrical Power atConstruction Sites (ANSI)NECA 202-2001, Recommended Practice for Installing and Maintaining Industrial Heat Tracing Systems (ANSI)NECA/FOA 30
33、1-1998, Standard for Installing and Testing Fiber Optic CablesNECA 305-2001, Standard for Fire Alarm System Job Practices (ANSI)NECA 400-1998, Recommended Practice for Installing and Maintaining Switchboards (ANSI)NECA 402-2001, Recommended Practice for Installing and Maintaining Motor Control Cente
34、rs (ANSI)NECA/EGSA 404-2000, Recommended Practice for Installing Generator Sets (ANSI)Annex A: Reference Standards13 a73(This annex is not part of the standard)a73 14NECA 405-2001, Recommended Practice for Installing and Commissioning Interconnected Generation Systems (ANSI)NECA 407-2002, Recommende
35、d Practice for Installing and Maintaining Panelboards (ANSI)NECA 408-2002, Recommended Practice for Installing and Maintaining Busways (ANSI)NECA 409-2002, Recommended Practice for Installing and Maintaining Dry-Type Transformers (ANSI)NECA/IESNA 500-1998, Recommended Practice for Installing Indoor
36、Commercial Lighting Systems (ANSI)NECA/IESNA 501-2000, Recommended Practice for Installing Exterior Lighting Systems (ANSI)NECA/IESNA 502-1999, Recommended Practice for Installing Industrial Lighting Systems (ANSI)NECA/BICSI 568-2001, Standard for Installing Commercial Building Telecommunications Cabling (ANSI)NECA/MACSCB 600-2003, Recommended Practice for Installing and Maintaining Medium-Voltage Cable (ANSI)
