tuberÃa emt-imc-rmc (wheatland)

Wheatland Tube Company

Hot-Dip GalvanizedSteel Rigid Metal Conduit (RMC)

Electrical Metallic Tubing (EMT)

Intermediate Metal Conduit (IMC)Inclu

des

2005 National

Electrica

l Code®®®®®

referen

ce

Wheatland Tube Company 2

From Start To Finish,You Get 100% Wheatland QualityWheatland controls the manufacture ofits hot-dip galvanized steel Rigid MetalConduit (RMC), Electrical Metallic Tub-ing (EMT) and Intermediate Metal Con-duit (IMC) every step of the way. We fab-ricate our own tubing from flat steel coils,weld it and do our own galvanizing. Thento be sure you get the same qualitythroughout the raceway system, wemake our own nipples, elbows, and cou-

Wheatland Tube Company and affiliatedcompanies manufacture steel tubulargoods exclusively. Wheatland steel RigidMetal Conduit, Electrical Metallic Tubingand Intermediate Metal Conduit are pro-duced on the most modern equipment inthe world. The smallest detail is givencareful attention to assure you the high-

plings to match. In fact, we’re the onlyconduit manufacturer who does.

It’s not surprising that Wheatland, of allconduit suppliers, has the expertise andresources to do the complete job. ForWheatland, as a major manufacturer ofsteel pipe, has developed the processesand techniques necessary to the produc-tion of quality tubular products.

Wheatland steel Rigid Metal Conduit,EMT and IMC meet all applicable provi-sions of the Underwriters Laboratories,the National Electrical Code, and theAmerican National Standards Instituteand Federal Specifications. This conform-ance to specifications is covered in de-tail on pages 3 to 12 and may be usedas reference in submitting bids.

Specialists In Steel Pipeest standards of product quality.Wheatland steel Rigid Metal Conduit iswidely known for the finest hot-dip galva-nizing and hot-zinc-coated threads in theindustry. A specially formulated coatinginhibits oxidation. The galvanized coat-ing is uniform and flake-proof. The con-duit cuts, threads, and bends easily be-

cause of Wheatland’s controlled process-ing.Wheatland Electrical Metallic Tubing andIntermediate Metal Conduit are manufac-tured on modern electric resistance weldmills, galvanized in line, and sprayed withspecial coatings for ease of pulling wiresand to inhibit white rust and storage stain.

General InformationAuthority Having Jurisdiction (AHJ)

All jurisdictions responsible for electricalinstallations neither automatically adoptthe current edition of the National Elec-trical Code® nor do they implement it uni-formly. Therefore, it is good practice tocheck with the authority having jurisdic-tion for local interpretations of the rulesand approval of equipment and materialsbefore beginning installation.

Other Articles and Sections of theNational Electrical Code

The three NEC® 2005 Articles containedin this brochure specifically address theinstallation of electrical steel racewaysproduced by Wheatland. They represent

only a small segment of the code whichmay be amended by other Articles or Sec-tions, depending on the installation. Thesafe installations of these raceways re-quire that all applicable Articles and Sec-tions of the code be observed.

The National Electrical Code® is publishedevery three years. The next edition is duein 2008.

Federal Specifications

The Federal government, in an effort toreduce costs, has undertaken a processof identifying non-government and indus-try-wide practices that have been acceptedpreviously by the Department of Defense

under the Single Process Initiative (SPI)for use in lieu of a specific military orFederal Specification or standard. Thisprocess reduces the burden of the gov-ernment to produce and maintain a sepa-rate standard.

Federal agencies accept UL 6where applicable to steel Rigid MetalConduit and UL1242 whereapplicable to Intermediate MetalConduit in lieu of WW-C-581.

Federal agencies acceptAmerican National StandardsInstitute ANSI C80.3 and UL 797where applicable to ElectricalMetallic Tubing in lieu ofWW-C-563.

Wheatland Tube Company3

WEIGHTS AND DIMENSIONS

in. in.

½¾11¼1½22½33½4

Weight10 Unit Lengths

162127354153637891

103

mm

17.9323.4229.5438.3544.2055.8073.0388.90

101.60114.30

.042

.049

.057

.065

.065

.065

.072

.072

.083

.083

mm

1.071.241.451.651.651.651.831.832.112.11

lb kg

OutsideDiameter(1)

WallThickness(2)

0.7060.9221.1631.5101.7402.1972.8753.5004.0004.500

13.620.930.445.852.667.198.0

119.3158.3178.3

Electrical Metallic Tubing - (EMT)

in. mm

15.8020.9326.6435.0540.8952.5069.3785.2497.38

110.08

InsideDiameter(2)

0.6220.8241.0491.3801.6102.0672.7313.3563.8344.334

MetricDesignator

TradeSize

PACKAGING

Cu. Ft.

½¾11¼1½22½33½4

162127354153637891

103

31.736.136.538.237.946.741.548.948.650.0

Cu. m

0.91.01.01.11.11.31.21.41.41.4

VolumePer Lift

1001001005050—————

QuantityPer Bundle

30.530.530.515.215.2—————

MetersFeet

21341524

914610457366186155113

91

700050003000200015001200

610510370300

KilogramsPounds

952.51043.3911.7916.3789.3805.6597.8608.3585.6534.8

WeightPer Lift

2100230020102020174017761318134112911179

BundlesPieces

7050304030—————

QuantityPer Lift

MetersFeet

MetricDesignator

TradeSize

Use of Wheatland Electrical Metallic Tubing inConformance to the 2005 National Electrical Code®

Article 358Electrical Metallic Tubing: Type EMT

I. General

358.1 Scope. This article covers the use,installation, and construction specifica-tions for electrical metallic tubing (EMT)and associated fittings.

358.2 Definition.

Electrical Metallic Tubing (EMT). Anunthreaded thinwall raceway of circularcross section designed for the physicalprotection and routing of conductors andcables and for use as an equipmentgrounding conductor when installedutilizing appropriate fittings. EMT is

generally made of steel (ferrous) withprotective coatings or aluminum (nonfer-rous).

358.6 Listing Requirements. EMT, factoryelbows, and associated fittings shall belisted.

304667

101116148216263349393

—————

12061513730

BundleTapeColor

BlackRedBlueRed

Black—————

NOTES: (1) Outside diameter subject to UL 797 tolerances.(2) For information only, not a UL 797 requirement.

Reprinted with permission from NFPA 70-2005, National Eectrical Code®, Copyright© 2004, National Fire Protection Association, Quincy, MA 02169. This reprinted material is not the complete and officialposition of the NFPA on the referenced subject, which is represented only by the standard in its entirety.


II. Installation

358.10 Uses Permitted.

(A) Exposed and Concealed. The use of EMTshall be permitted for both exposed and con-cealed work.

(B) Corrosion Protection. Ferrous or non-ferrous EMT, elbows, couplings, and fittingsshall be permitted to be installed in concrete,in direct contact with the earth, or in areassubject to severe corrosive influences whereprotected by corrosion protection andjudged suitable for the condition.

(C) Wet Locations. All supports, bolts,straps, screws, and so forth shall be of cor-rosion-resistant materials or protectedagainst corrosion by corrosion-resistantmaterials.

FPN: See 300.6 for protection againstcorrosion.

358.12 Uses Not Permitted. EMT shall notbe used under the following conditions:(1) Where, during installation or afterward,it will be subject to severe physical damage(2) Where protected from corrosion solelyby enamel(3) In cinder concrete or cinder fill wheresubject to permanent moisture unless pro-tected on all sides by a layer of noncinderconcrete at least 50 mm (2 in.) thick or un-less the tubing is at least 450 mm (18 in.)under the fill(4) In any hazardous (classified) locationexcept as permitted by 502.10, 503.10, and504.20(5) For the support of luminaries (fixtures)or other equipment except conduit bodiesno larger than the largest trade size of thetubing(6) Where practicable, dissimilar metals incontact anywhere in the system shall beavoided to eliminate the possibility of gal-vanic action

Exception: Aluminum fittings and enclo-sures shall be permitted to be used withsteel EMT where not subject to severe cor-rosive influences.

358.20 Size.

(A) Minimum. EMT smaller than metric des-ignator 16 (trade size ½) shall not be used.

Exception: For enclosing the leads of mo-tors as permitted in 430.245 (B).

(B) Maximum. The maximum size of EMTshall be metric designator 103 (trade size 4).

FPN: See 300.1(C) for the metric desig-nators and trade sizes. These are for identi-fication purposes only and do not relate toactual dimensions. [See page 7]

358.22 Number of Conductors. The num-ber of conductors shall not exceed that per-mitted by the percentage fill specified inTable 1, Chapter 9. [See page 7]

Cables shall be permitted to be in-stalled where such use is not prohibited bythe respective cable articles. The numberof cables shall not exceed the allowable per-centage fill specified in Table 1, Chapter 9.[See page 7]

358.24 Bends - How Made. Bends shall bemade so that the tubing is not damaged andthe internal diameter of the tubing is not ef-fectively reduced. The radius of the curveof any field bend to the centerline of thetubing shall not be less than shown in Table2, Chapter 9 for one-shot and full shoebenders. [See page 10]

358.26 Bends - Number in One Run. Thereshall not be more than the equivalent of fourquarter bends (360 degrees total) betweenpull points, for example, conduit bodies andboxes.

358.28 Reaming and Threading.

(A) Reaming. All cut ends of EMT shall bereamed or otherwise finished to removerough edges.

(B) Threading. EMT shall not be threaded.

Exception: EMT with factory threaded in-tegral couplings complying with 358.100.

358.30 Securing and Supporting. EMTshall be installed as a complete system inaccordance with 300.18 and shall be securelyfastened in place and supported in accor-dance with 358.30 (A) and (B).

(A) Securely Fastened. EMT shall be se-curely fastened in place at least every 3 m(10 ft). In addition, each EMT run betweentermination points shall be securely fastenedwithin 900 mm (3 ft) of each outlet box, junc-tion box, device box, cabinet, conduit body,or other tubing terminations.

Exception No. 1: Fastening of unbrokenlengths shall be permitted to be increasedto a distance of 1.5 m (5 ft) where struc-tural members do not readily permit fas-tening within 900 mm (3 ft).

Exception No. 2: For concealed work infinished buildings or prefinished wall pan-els where such securing is impracticable,unbroken lengths (without coupling) ofEMT shall be permitted to be fished.

(B) Supports. Horizontal runs of EMT sup-ported by openings through framing mem-bers at intervals not greater than 3 m (10 ft)and securely fastened within 900 mm (3 ft)of termination points shall be permitted.

358.42 Couplings and Connectors.Couplings and connectors used with EMTshall be made up tight. Where buried in ma-sonry or concrete, they shall beconcretetight type. Where installed in wetlocations, they shall comply with 314.15(A).

358.56 Splices and Taps. Splices and tapsshall be made in accordance with 300.15.

358.60 Grounding. EMT shall be permittedas equipment grounding conductor.

III. Construction Specifications

358.100 Construction. Factory-threadedintegral couplings shall be permitted. WhereEMT with a threaded integral coupling isused, threads for both the tubing and cou-pling shall be factory-made. The couplingand EMT threads shall be designed so asto prevent bending of the tubing at any partof the thread.

358.120 Marking. EMT shall be clearly anddurably marked at least every 3 m (10 ft) asrequired in the first sentence of 110.21.




in. in.

½¾11¼1½22½33½4

Weight10 Unit Lengthswith Couplings

162127354153637891

103

mm

20.7026.1432.7741.5947.8259.9372.5788.29

100.86113.44

.078

.083

.093

.095

.100

.105

.150

.150

.150

.150

mm

1.972.102.352.412.542.673.813.813.813.81

lb kg

Nominal(1)Outside

Diameter

Nominal(1)Wall

Thickness

6284

119158194256441543629700

0.8151.0291.2901.6381.8832.3602.8573.4763.9714.466

28.1238.1053.9871.6788.00

116.12200.04246.30285.31317.52

Intermediate Metal Conduit - (IMC)

in. mm

16.7622.0728.0736.7742.7454.6064.9580.6793.24

105.82

Nominal(2)Inside

Diameter

0.6600.8691.1051.4481.6832.1502.5573.1763.6714.166

ThreadsPerInch

141411½11½11½11½8888

Acceptable Length of FinishedConduit Without Coupling

mm(+/- 6 mm)

ft. in.(+/- ¼ in.)

9999999999

3030303030253025302530253010301030053005

11¼11¼1111111110½10½10¼10¼

PACKAGING

Cu. Ft.

½¾11¼1½22½33½4

162127354153637891

103

26.433.532.134.735.030.933.538.341.748.6

Cu. m

0.70.90.91.01.00.90.91.11.21.4

VolumePer Lift

YellowGreen

OrangeGreenYellowOrangeYellowOrangeYellowOrange

ThreadProtectors

Color

1005050———————

Feet Meters

30.515.215.2

———————

MetersFeet

1067762518411335244113

917373

35002500170013501100

800370300240240

KilogramsPounds

984.3952.5917.6967.5968.0929.0740.3738.9684.9762.0

WeightPer Lift

2170210020232133213420481632162915101680

BundlesPieces

355034———————

———

135110

8037302424

NOTES: (1) Figures are the average of the maximum and minimum dimensions as given in UL 1242.

QuantityPer Lift

QuantityPer Bundle

MetricDesignator

TradeSize

MetricDesignator

TradeSize

(2) Calculated from nominal outside diameter and wall thickness.


Use of Intermediate Metal Conduit In ConformanceTo The 2005 National Electrical Code®

Article 342Intermediate Metal Conduit: TypeIMC

I. General

342.1 Scope. This article covers the use,installation, and construction specificationsfor intermediate metal conduit (IMC) andassociated fittings.

342.2 Definition.

Intermediate Metal Conduit (IMC). A steelthreadable raceway of circular cross sectiondesigned for the physical protection androuting of conductors and cables and foruse as an equipment grounding conductorwhen installed with its integral or associ-ated couplings and appropriate fittings.

342.6 Listing Requirements. IMC, factoryelbows and couplings, and associated fit-tings shall be listed.

II. Installation

342.10 Used Permitted.

(A) All Atmospheric Conditions and Occu-pancies. Use of IMC shall be permitted un-der all atmospheric conditions and occupan-cies.

(B) Corrosion Environments. IMC, elbows,couplings, and fittings shall be permitted tobe installed in concrete, in direct contactwith the earth, or in areas subject to severecorrosive influences where protected bycorrosion protection and judged suitable forthe condition.

(C) Cinder Fill. IMC shall be permitted tobe installed in or under cinder fill where sub-ject to permanent moisture where protectedon all sides by a layer of noncinder concretenot less than 50 mm (2 in.) thick; where the

conduit is not less than 450 mm (18 in.) un-der the fill; or where protected by corrosionprotection and judged suitable for the con-dition.

(D) Wet Locations. All supports, bolts,straps, screws, and so forth, shall be of cor-rosion-resistant materials or protectedagainst corrosion by corrosion-resistant ma-terials.

FPN: See 300.6 for protection against cor-rosion.

342.14 Dissimilar Metals. Where practi-cable, dissimilar metals in contact anywherein the system shall be avoided to eliminatethe possibility of galvanic action. Aluminum fittings and enclosures shall bepermitted to be used with IMC.

342.20 Size.

(A) Minimum. IMC smaller than metric des-ignator 16 (trade size ½) shall not be used.

(B) Maximum. IMC larger than metric des-ignator 103 (trade size 4) shall not be used.

FPN: See 300.1(C) for the metric desig-nator and trade sizes. These are for identifi-cation purposes only and do not relate toactual dimensions. [See page 7]

342.22 Number of Conductors. The num-ber of conductors shall not exceed that per-mitted by the percentage fill specified inTable 1, Chapter 9. [See page 7] Cables shall be permitted to be installedwhere such use is not prohibited by the re-spective cable articles. The number ofcables shall not exceed the allowable per-centage fill specified in Table 1, Chapter 9.[See page 7]

342.24 Bends - How Made. Bends of IMCshall be so made that the conduit will not be

damaged and the internal diameter of theconduit will not be effectively reduced. Theradius of the curve of any field bend to thecenterline of the conduit shall not be lessthan indicated in Table 2, Chapter 9. [Seepage 10]

342.26 Bends - Number in One Run. Thereshall not be more than the equivalent of fourquarter bends (360 degrees total) betweenpull points, for example, conduit bodies andboxes.

342.28 Reaming and Threading. All cutends shall be reamed or otherwise finishedto remove rough edges. Where conduit isthreaded in the field, a standard cutting diewith a 1 in 16 (¾ in. taper per foot) shall beused.

FPN: See ANSI/ASME B.1.20.1-1983,Standard for Pipe Threads, GeneralPurpose (Inch).

342.30 Securing and Supporting. IMC shallbe installed as a complete system in accor-dance with 300.18 and shall be securely fas-tened in place and supported in accordancewith 342.30(A) and (B).

(A) Securely Fastened. Each IMC shall besecurely fastened within 900 mm (3 ft) ofeach outlet box, junction box, device box,cabinet, conduit body, or other conduit ter-mination. Fastening shall be permitted to beincreased to a distance of 1.5 m (5 ft) wherestructural members do not readily permit fas-tening within 900 mm (3 ft). Where approved,conduit shall not be required to be securelyfastened within 900 mm (3 ft) of the servicehead for above-the-roof termination of amast.(B) Supports. IMC shall be supported in ac-cordance with one of the following:(1) Conduit shall be supported at intervalsnot exceeding 3 m (10 ft).(2) The distance between supports for



straight runs of conduit shall be permittedin accordance with Table 344.30(B)(2), pro-vided the conduit is made up with threadedcouplings and such supports prevent trans-mission of stresses to termination whereconduit is deflected between supports.(3) Exposed vertical risers from industrialmachinery or fixed equipment shall be per-mitted to be supported at intervals not ex-ceeding 6 m (20 ft) if the conduit is made upwith threaded couplings, the conduit is sup-ported and securely fastened at the top andbottom of the riser, and no other means ofintermediate support is readily available.(4) Horizontal runs of IMC supported byopenings through framing members at inter-vals not exceeding 3 m (10 ft) and securelyfastened within 900 mm (3 ft) of terminationpoints shall be permitted.

342.42 Couplings and Connectors.

(A) Threadless. Threadless couplings andconnectors used with conduit shall be madetight. Where buried in masonry or concrete,they shall be the concretetight type. Whereinstalled in wet locations, they shall complywith 314.15(A). Threadless couplings andconnectors shall not be used on threadedconduit ends unless listed for the purpose.

(B) Running Threads. Running threadsshall not be used on conduit for connectionat couplings.

342.46 Bushings. Where a conduit entersa box, fitting, or other enclosure, a bushingshall be provided to protect the wire fromabrasion unless the design of the box, fit-ting, or enclosure is such as to afford equiva-lent protection.

FPN: See 300.4(F) for the protection ofconductors 4 AWG and larger at bushings.


342.60 Grounding. IMC shall be permittedas an equipment grounding conductor.


342.120 Marking. Each length shall beclearly and durably marked at least every1.5 m (5 ft) with the letters IMC. Each lengthshall be marked as required in 110.21.

342.130 Standard Lengths. The standardlength of IMC shall be 3.05 m (10 ft), includ-ing an attached coupling, and each end shallbe threaded. Longer or shorter lengths withor without coupling and threaded orunthreaded shall be permitted.

After Article 250 was revised in the 1990NEC®, the steel conduit producers initi-ated a program to evaluate the perfor-mance of steel EMT, IMC, and Rigid MetalConduit during faults in secondary distri-bution systems.

Georgia Institute of Technology, Atlanta,GA undertook the research and in 1994

Grounding Study on Steel EMT,IMC, and Rigid Conduit

published their findings in a report thatupdated the grounding data developed byEustace Soares, some 40 years ago, andanswered the questions of compliancewith NEC® Article 250.

”Modeling and Testing of SteelEMT, IMC, and Rigid (GRC)Conduit” Study, Part I.

Part II, Contains Appendices ofTest Results.

You can download or view the study at,w w w . s t e e l c o n d u i t . o r g /free_downloads.htm.

srotcudnoCforebmuN sepyTrotcudnoCllA

1 352 13

2revO 04

Table 1 Percent of Cross Section of Conduitand Tubing for Conductors

Chapter 9 Tables


rotangiseDcirteM eziSedarT21 8/361 2/112 4/372 153 4/1114 2/1135 236 2/7287 319 2/13301 4921 5551 6

Table 300.1(C) Metric Designator andTrade Sizes

Note: The metric designators and trade sizes arefor identification purposes only and are not actualdimensions.

From Article 300 Wiring Methods



in. in.

½¾11¼1½22½33½456

Weight10 Unit Lengthswith Couplings

TradeSize

mm

21.3426.6733.4042.1648.2660.3373.0388.90

101.60114.30141.30168.28

.104

.107

.126

.133

.138

.146

.193

.205

.215

.225

.245

.266

mm

2.642.723.203.383.513.714.905.215.465.726.226.76

lb kg

MetricDesignator

82109161218263350559727880

103014001840

0.8401.0501.3151.6601.9002.3752.8753.5004.0004.5005.5636.625

37.2049.4473.0398.88

119.30158.76253.56329.77399.17467.21635.04834.62

Hot-Dip GalvanizedRigid Metal Conduit - Steel (RMC)

in. mm

16.0521.2327.0035.4141.2552.9163.2278.4990.68

102.87128.85154.76

0.6320.8361.0631.3941.6242.0832.4893.0903.5704.0505.0736.093

ThreadsPerInch

141411½11½11½11½888888

Acceptable Length of FinishedConduit Without Coupling

mm(+/- 6 mm)

ft. in.(+/- ¼ in.)

999999999999

303030303025302530253025301030103005300529952995

11¼11¼1111111110½10½10¼10¼1010

PACKAGING

Cu. Ft.

½¾11¼1½22½33½456

162127354153637891

103129155

19.426.722.228.327.236.135.041.543.348.652.143.8

Cu. m

0.60.80.60.80.81.01.01.21.21.41.51.2

VolumePer Lift

BlackRedBlueRed

BlackBlueBlackBlueBlackBlueBlueBlue

ThreadProtectors

Color

1005050—————————

Feet Meters

30.515.215.2

—————————

MetersFeet

762610381274244183113

9176614630

2,5002,0001,250

900800600370300250200150100

KilogramsPounds

929.9988.8913.1889.9954.4952.5938.0989.3997.9934.4952.5834.6

WeightPer Lift

205021802013196221042100206821812200206021001840

BundlesPieces

254025—————————

QuantityPer Lift

———908060373025201510

162127354153637891

103129155

TradeSize

MetricDesignator

QuantityBundle

OutsideDiameter*

WallThickness*

InsideDiameter*

*For information only, not a UL 6 requirement.


Use of Wheatland Rigid Metal Conduit - Steel inConformance to the 2005 National Electrical Code®

Article 344Rigid Metal Conduit: Type RMC

I. General

344.1 Scope. This article covers the use, in-stallation, and construction specifications forrigid metal conduit (RMC) and associated fit-tings.

344.2 Definition.

Rigid Metal Conduit (RMC). A threadableraceway of circular cross section designedfor the physical protection and routing of con-ductors and cables and for use as an equip-ment grounding conductor when installed withits integral or associated coupling and asso-ciated fittings. RMC is generally made of steel(ferrous) with protective coatings or aluminum(nonferrous). Special use types are siliconbronze and stainless steel.

344.6 Listing Requirements. RMC, factoryelbows and couplings, and associated fittingsshall be listed.

II. Installation

344.10 Uses Permitted.

(A) All Atmospheric Conditions and Occupan-cies. Use of RMC shall be permitted under allatmospheric conditions and occupancies. Fer-rous raceways and fittings protected from cor-rosion solely by enamel shall be permitted onlyindoors and in occupancies not subject to se-vere corrosive influences.

(B) Corrosion Environments. RMC, elbows,couplings, and fittings shall be permitted tobe installed in concrete, in direct contact withthe earth, or in areas subject to severe corro-sive influences where protected by corrosionprotection and judged suitable for the condi-tion.

(C) Cinder Fill. RMC shall be permitted to beinstalled in or under cinder fill where subject topermanent moisture where protected on allsides by a layer of noncider concrete not lessthan 50 mm (2 in.) thick; where the conduit isnot less than 450 mm (18 in.) under the fill; orwhere protected by corrosion protection andjudged suitable for the condition.

(D) Wet Locations. All supports, bolts, straps,screws, and so forth, shall be of corrosion-resistant materials or protected against corro-sion by corrosion-resistant materials.

FPN: See 300.6 for protection against cor-rosion.

344.14 Dissimilar Metals. Where practicable,dissimilar metals in contact anywhere in thesystem shall be avoided to eliminate the possi-bility of galvanic action. Aluminum fittings andenclosures shall be permitted to be used withsteel RMC, and steel fittings and enclosuresshall be permitted to be used with aluminumRMC where not subject to severe corrosiveinfluences.

344.20 Size.

(A) Minimum. RMC smaller than metric desig-nator 16 (trade size ½) shall not be used.

Exception: For enclosing the leads of motorsas permitted in Section 430.245 (B).

(B) Maximum. RMC larger than metric desig-nator 155 (trade size 6 ) shall not be used.

FPN: See 300.1(C) for the metric designa-tors and trade sizes. These are for identifica-tion purposes only and do not relate to actualdimensions. [See page 7]

344.22 Number of Conductors. The numberof conductors shall not exceed that permitted

by the percentage fill specified in Table 1, Chap-ter 9. [See page 7]

Cables shall be permitted to be in-stalled where such use is not prohibited by therespective cable articles. The number of cablesshall not exceed that allowable percentage fillspecified in Table 1, Chapter 9. [See page 7]

344.24 Bends - How Made. Bends of RMCshall be so made that the conduit will not bedamaged and so that the internal diameter ofthe conduit will not be effectively reduced. Theradius of the curve of any field bend to thecenterline of the conduit shall not be less thanindicated in Table 2, Chapter 9. [See page 10]

344.26 Bends - Number in One Run. Thereshall not be more than the equivalent of fourquarter bends (360 degrees total) between pullpoints, for example, conduit bodies and boxes.

344.28 Reaming and Threading. All cutends shall be reamed or otherwise finished toremove rough edges. Where conduit isthreaded in the field, a standard cutting diewith a 1 in 16 taper (¾-in. taper per foot) shallbe used.

FPN: See ANSI/ASME B.1.20.1-1983, Stan-dard for Pipe Threads, General Purpose(Inch).

344.30 Securing and Supporting. RMC shallbe installed as a complete system in accor-dance with 300.18 and shall be securely fas-tened in place and supported in accordancewith 344.30(A) and (B).

(A) Securely Fastened. RMC shall be se-curely fastened within 900 mm (3 ft) of eachoutlet box, junction box, device box, cabi-net, conduit body, or other conduit termina-tion. Fastening shall be permitted to be in-creased to a distance of 1.5 m (5 ft) wherestructural members do not readily permit fas-tening within 900 mm (3 ft). Where approved,



conduit shall not be required to be securelyfastened within 900 mm (3 ft) of the servicehead for above-the-roof termination of amast.

(B) Supports. RMC shall be supported inaccordance with one of the following:(1) Conduit shall be supported at intervalsnot exceeding 3 m (10 ft)(2) The distance between supports forstraight runs of conduit shall be permittedin accordance with Table 344.30(B)(2), pro-vided the conduit is made up with threadedcouplings and such supports prevent trans-mission of stresses to termination whereconduit is deflected between supports.(3) Exposed vertical risers from industrialmachinery or fixed equipment shall be per-mitted to be supported at intervals not ex-ceeding 6 m (20 ft) if the conduit is made upwith threaded couplings, the conduit is sup-ported and securely fastened at the top andbottom of the riser, and no other means ofintermediate support is readily available.(4) Horizontal runs of RMC supported byopenings through framing members at inter-vals not exceeding 3 m (10 ft) and securelyfastened within 900 mm (3 ft) of terminationpoints shall be permitted.

344.42 Couplings and Connectors.

(A) Threadless. Threadless couplings andconnectors used with conduit shall be madetight. Where buried in masonry or concrete,they shall be the concretetight type. Whereinstalled in wet locations, they shall complywith 314.15(A). Threadless couplings andconnectors shall not be used on threadedconduit ends unless listed for the purpose.

eziStiudnoCecnatsiDmumixaM

lateMdigiRneewteBstroppuStiudnoC

cirteMrotangiseD

edarTeziS m tf

12-61 1/2 - 3/4 0.3 01

72 1 7.3 21

14-53 11/4 1- 1/2 3.4 41

36-35 2-2 1/2 9.4 61dna87regral

dna3regral 1.6 02

Table 344.30(B)(2) Supports for RigidMetal Conduit

(B) Running Threads. Running threadsshall not be used on conduit for connectionat couplings.

344.46 Bushings. Where a conduit entersa box, fitting, or other enclosure, a bushingshall be provided to protect the wire fromabrasion unless the design of the box, fit-ting, or enclosure is such as to afford equiva-lent protection.

FPN: See 300.4(F) for the protec-tion of conductors sizes 4 AWG and largerat bushings.


344.60 Grounding. RMC shall be permittedas an equipment grounding conductor.


344.120 Marking. Each length shall beclearly and durably identified in every 3 m(10 ft) as required in the first sentence of110.21. Nonferrous conduit of corrosion-re-sistant material shall have suitable markings.

344.130 Standard Lengths. The standardlength of RMC shall be 3.05 m (10 ft), includ-ing an attached coupling, and each end shallbe threaded. Longer or shorter lengths withor without coupling and threaded orunthreaded shall be permitted.

eziSgnibuTrotiudnoC eohSlluFdnatohSenOsredneB sdneBrehtO

cirteMrotangiseD eziSedarT mm .ni mm .ni

61 2/1 6.101 4 6.101 4

12 4/3 3.411 2/14 721 5

72 1 50.641 4/35 4.251 6

53 4/11 51.481 2/17 2.302 8

14 2/11 55.902 4/18 452 01

35 2 3.142 2/19 8.403 21

36 2/12 7.662 2/101 183 51

87 3 2.033 31 2.754 81

19 2/13 183 51 4.335 12

301 4 4.604 61 6.906 42

921 5 6.906 42 267 03

551 6 267 03 4.419 63

Chapter 9 Tables

Table 2 Radius of Conduit and Tubing Bends


Need 20 Foot Lengths of Rigid or EMT?

Contact Wheatland Electrical sales department E-mail: [email protected],

Phone : 800-257-8182, or Fax: 856-854-4973


Steel conduit will provide many benefitsin your electrical distribution system. Steelconduit can dramatically reduce electro-magnetic fields, thus reducing electro-magnetic interference created by typicalpower frequency electrical wiring. Steelconduit systems can be designed for thebest grounding. And steel conduit pro-vides the well-known benefits of physi-cal protection for conductors and firesafety.

All New Grounding andElectroMagnetic Interference (GEMI)Analysis Software

Developed specifically to assist architects,electrical engineers, electrical contractors,building and facility operation profession-als with issues involving:

Electromagnetic interference inelectrical distribution systems

Steel Conduit For EMI SolutionsMost effective conduit forelectromagnetic field reduction

Harmonics in electrical systems

Design of distribution feeder andbranch circuits for safety andeconomics

Equipment grounding

Easy and accurate calculation ofconduit runs for effective groundingpath

Analysis of existing circuits

GEMI was researched, designed and writ-ten at the School of Electrical and Com-puter Engineering, Georgia Institute ofTechnology, Atlanta, GA.

The GEMI software program, which canbe used to address the effects of EMI oncommonly used electronic equipment, hasbeen validated with actual measurementsof EMF and the most exhaustive studiesof impedance and permeability of steelconduit in 40 years.

GEMI permits flexibility in the design of anew system, comparison with other typesystems designed to the equipmentgrounding requirements of the NEC, andanalysis of existing systems to determineany upgrading necessary for safe groundfault interruption or reduced electromag-netic fields.

To obtain a copy of the GEMI softwarecontact Wheatland’s Marketing Depart-ment at [email protected]. The soft-ware is free to qualified users.

Wheatland Nipples, Elbows, and CouplingsWheatland has a complete line ofnipples, elbows, and couplings for Rigidsteel and aluminum conduit, and elbowsfor steel IMC and EMT.

Nipple, Elbow and CouplingStandardsThe material standards that coverWheatland’s standard length conduit and

tubing cover our tubular fittings as well.As a convenience to our customersWheatland inventories aluminum tubularfittings to ship with our steel fittings.Aluminum nipples, elbows and couplingsconform to UL 6A, Federal SpecificationWW-C-540, and American NationalStandards Institute C80.5.

For complete information on weights,dimensions, and packaging ask for ourproduct bulletins. Hot-dip GalvanizedRigid Conduit nipples, elbows andcouplings are covered in one publicationand Aluminum and IMC products inanother.

Underwriters Laboratories report UL Re-port on Electrical Metallic Tubing For UseOver 600 Volts, January 19, 1996 “identi-fied Electrical Metallic Tubing (EMT) assuitable for use where the voltage be-

Electrical Metallic Tubing For Use Over 600 Voltstween circuit conductors or between con-ductors and ground is over 600 volts.”For a copy of the UL report contactWheatland’s Marketing Department [email protected].


Applicable IMC Material StandardsThough the National Electrical Code®

deals primarily with proper field applica-tion, it presumes that the conduit meetsthe standards necessary to perform prop-erly under approved conditions.Wheatland Intermediate Metal Conduit ismade to provide all the qualities requiredfor proper installation as specified in theNEC®.

Wheatland Intermediate Metal Conduit ismanufactured in conformance to stan-dards established by the American Na-tional Standards Institute, the Underwrit-ers Laboratories and the Federal Specifi-

cation. In preparing bids, it may be statedthat Wheatland Intermediate Metal Con-duit Conforms to:

Underwriters LaboratoriesStandard UL 1242

Federal Specification WW-C-581

American National StandardInstitute C80.6

NEC® 2005 Section 250.118(3)recognizes IMC as an equipmentgrounding conductor.

Though the National Electrical Code®

deals primarily with proper field applica-tion, it presumes that the conduit meetsthe standards necessary to perform prop-erly under approved conditions.Wheatland galvanized steel Rigid MetalConduit is made to provide all the quali-ties required for proper installation asspecified in the NEC®.

Wheatland Galvanized steel Rigid MetalConduit is manufactured in conformanceto standards established by the Ameri-can National Standards Institute, the Un-derwriters Laboratories and the Federal

Applicable Rigid Metal Conduit -Steel Material Standards

Specification. In preparing bids, it maybe stated that Wheatland Galvanizedsteel Rigid Metal Conduit Conforms to:

Underwriters Laboratories StandardUL 6



NEC® 2005 Section 250.118(2)recognizes RMC as an equipmentgrounding conductor.

CORPORATE OFFICES:

Wheatland Tube Company900 Haddon Avenue

Collingswood, NJ 08108-2162Phone: 800-257-8182

Fax: 856-854-4973www.wheatland.com

FACTORYINVENTORY LOCATIONS:

Wheatland Tube Company6247 Navigation Blvd.Houston, TX 77011

Phone: 800-231-6345Fax: 713-928-8939

Wheatland Tube CompanyChicago Division

4435 South Western Blvd.Chicago, IL 60609-3024

Phone: 773-254-0617Fax: 773-254-2244

Wheatland Tube CompanyWheatland Division1 Council Avenue

Wheatland, PA 16161-0608Phone: 724-342-6851

Fax: 724-342-0294

Wheatland Tube Company200 Clark Street

Sharon, PA 16146Phone: 724-347-7771

Fax:724-346-7199

Wheatland Tube CompanyLittle Rock Division8200 Frazier Pike

Little Rock, AR 72206-3811Phone: 800-831-5682

Fax: 501-490-1011

Though the National Electrical Code®

deals primarily with proper field applica-tion, it presumes that the tubing meets thestandards necessary to perform properlyunder approved conditions. WheatlandElectrical Metallic Tubing is made to pro-vide all the qualities required for properinstallation as specified in the NEC®.

Wheatland Electrical Metallic Tubing ismanufactured in conformance to stan-dards established by the American Na-tional Standards Institute, the Underwrit-ers Laboratories and the Federal Specifi-

Applicable EMT Material Standardscation. In preparing bids, it may be statedthat Wheatland EMT Conforms to:

Underwriters LaboratoriesStandard UL 797



NEC® 2005 Section 250.118(4)recognizes EMT as an equipmentgrounding conductor.

tuberÃa emt-imc-rmc (wheatland)

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