ANSI C80.6-1994

8/21/2019 ANSI C80.6-1994

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ANSI C80.6-1994

Intermediate

Metal Conduit

Zinc Coated

N a t i o n a lE l e c t r i c a l

M a n u f a c t u r e r sA s s o c i a t i o n

1 3 0 0 N . 17th treet

S u i t e 1 8 4 7

R o s s l y n , V i r g i n i a

2 2 2 0 9

;anNational Standard

vith permission of the American

Ir resale. No part of this publication

n, electronic retrieval system or

lission of th e American National

:treet, New York New York 10036.

L merican NauOnal Standaj

703)

8 4 1 - 3 3 0 0

merican National Standards InstituteYRIGHT American National Standards Instituteensed by Information Handling Services

8/21/2019 ANSI C80.6-1994


A N S I

C B 0 . b

9 4 0724150 0535439 7 3 7 m

ANSI@

80.6-1994

American National Standard

Intermediate Metal Conduit-

Zinc Coated IMC)

Secretariat

National Electrical Manufacturers Association

Approved May1994

American National Standards Institution, Inc.

Abstract

This standard has been developed to specify dimensions and weights for zinc-coated steel intermediate

metal conduit, elbows, couplings and nipples for use as an electrical raceway. Trade size designators

(metric size designators) range from

/2

(16

IMC)

to

4

(103 IMC). Basic data for threads are included as

well as requisite tests

or

mechanical properties

of

the conduit.

merican National Standards InstituteYRIGHT American National Standards Institute

8/21/2019 ANSI C80.6-1994


ANSI C B 0 . b 9 4 07241150

0 5 3 5 4 4 0 459

America

National

n ApprovalofanAmericanNationalStandardequiresverificationby ANSI thathe

requirements

for

due process, consensus, andother criteria for approval havebeen met

by the standards developer.

Standard

Consensussestablishedwhen,nheudgmentofheANSI bard ofStandards

Review, substantial agreement has been reached by directly and materially affected

interests.Substantialagreementmeansmuchmore hanasimplemaprity, but not

necessarily unanimity. Consensus requires that all viewsand objections be considered,

and thata concerted effortbe made toward their resolution.

The use of American National Standards is completely voluntary; their existence does

not in any respect preclude anyone, whether he has approved the standards or not, from

manufacturing, marketing, purchasing,

or

using products, processes, or procedures not

conforming to the standards.

The American National Standards Institute does not develop standards and will n no

circumstances give an interpretation of any American National Standard. Moreover,

no

person

shall have the right

r

authority to issue an interpretation

f

an American National

Standard in

thenameof heAmericanNationalStandards nstitute.Requests or

interpretations

should

be addressed to the secretariat orsponsor whose name appears

on the title

page

of this standard.

CAUTION NOTICE:

This American National Standard may be revised

or

withdrawn

at

any ime. The procedures

of

the American National Standards nstitute require hat

action be taken to reaffirm, revise,orwithdraw this standard no later than fwe years from

the date of

approval.

Purchasers of American National Standards may receive current

informationonallstandardsbycallingorwriting heAmericanNationalStandards

Institute.

Published by

National ElectricalManufacturersAssociation

1300N. 17th

Street, Rosslyn, Virginia

22209

Copyright

O

1995 by American National Standards Institute,nc.

All

rights reserved.

Printed in the United States

f

America

AlM11W6

merican National Standards InstituteYRIGHT American National Standards Instituted b I f ti H dli S i

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ANSI

C8O.b 94

0 7 2 4 3 5 0 0 5 3 5 4 4 3 395

ANSI C80.6-1994

Contents

PAGE

Foreword......................................................................................................................................................... i

2 Normativeeferences ........................................................................................................................... 1

3 Definrtlons 1

4

Unitsof measurements ........................................................................................................................ 1

5 Generalequirements ........................................................................................................................... 1

5.1 Circularcross section ................................................................................................................ 1

5.2

Wall hickness

............................................................................................................................

1

5.3 Interiorsurface ........................................................................................................................... 2

5.4 Welding

......................................................................................................................................

2

5.5 Cleaning

.....................................................................................................................................

2

5.6

Protectivecoating ......................................................................................................................

2

6 Detailedequirements

...........................................................................................................................

2

6.1

Zinc coating ............................................................................................................................... 2

6.2 Enamel or equivalent coating ..................................................................................................... 2

6.3

Threading and chamfering

.........................................................................................................

2

6.4

Identification .............................................................................................................................. 2

6.5

Dimensions................................................................................................................................

2

6.6 Threads ..................................................................................................................................... 2

6.7

Couplings

................................................................................................................................... 2

6 8

Elbows, bends and nipples ........................................................................................................ 3

7 Testprocedures .................................................................................................................................... 3

7.1 Bendingproperties ..................................................................................................................... 3

7.3 QuaMy of enamel coating for use on interior surfaces.............................................................. 4

8

Examinationof product.........................................................................................................................

4

8.1 Placeof inspection .................................................................................................................... 4

8.2 V i a l nspection........................................................................................................................ 4

8.3

Retests

....................................................................................................................................... 4

9

Markingdentifikation ............................................................................................................................ 4

1 scope

...................................................................................................................................................

1

..

.............................................................................................................................................

7.2 Thicknessof zinc coating ........................................................................................................... 3

1


8/21/2019 ANSI C80.6-1994


ANSI (380.6-1994

This

standard was

developed

by

the Accredited Standards Committee on Raceways for

Electrical

Wiring

Systems, C80 The obpctive

of the committee

s

to

produce

a comprehensive

specification

that would establish

uniform dimensions and standard construction requirements for

rigid

metal conduit, electrical metallic tubing,

intermediate

metal

cow¡

and

rigid

aluminumconduit

raceway

products

and

their associated

components.

The standardwas originally

approved

in 1986.

uggestions

for

mprovement

of

this

standard will

be

welcome.

They should be

sent to the National

Electrical

Manufacturers Association,

1300

N. 17th Street, Rosslyn, Virginia

22209.

This standard was processed and

approved

for submittal to

ANSI

by the Accredited standardsCommittee on

Raceways forElectrical Wiring Systems,

C80

Committee approval of the standard

oes

not necessarily imply

that

all

committee members

voted for its approval. At

the

time it approved

this

standard,

the

C80

Committee

had

the fdlOWng

members:

J. A Gmber, Chairman

J.

A.

Gauthier, Secretary

rganizathnRepresented

Aluminum

Association

American Iron

and steel

Institute

American Ppe F ~ i n g sssociation

International AssocWin of

Electrical Inspectors

InternationalBrathemoodofElectrical

Workers

NationaiElectrical Contractors Association

NationalElectrical Manufacturers Association

ame of Representative

P.

Pollak

M. Pahoda

R. T. Bryson

W. tirly

K. R. Edwards

J. Widener

C.

H.Williams

A. W.

allard

C. W. Beile

D.

Gearing

J. A.

Gruber

J H.

Kuczka

T.

McNeive

S.Schauffele

R. Hggenbottom Alt.)

P.

Horton

Alt.)

R.

Jazowski Alt.)

F.W.

McGeehan

G. Rusinski

R.

LaRocca Al t . )


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A N S I C B O b

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AMERICAN w n o w L

STANDARD ANSI C80.6-1994

American National Standard for Intermediate Metal Conduit1MC

Zinc Coated

1.1 This standard covers he requirements or ntermediate metal conduit or use as a raceway or he

wires or cables of an electrical system.The conduit is furnished in nominal 0 4 3.05m)engths,threaded on

each end with one coupling attached.

t

is protected on the exterior surface with a metallic zinc coating and

n

t he interior surface with a zinc, enamel, or other equivalent corrosion-resistant coating.

1.2

his

standard also covers conduit couplings, elbows, bends, and nipples and engths other than 10 f t

(3.05

m).

2

Normative

reference

The

following standard contains provisions which, through reference in this text, constitute provisions of this

American National Standard. At the time of publication,he edition indicated was valid.l l

standards

are subject

to revision,and parties to agreements based on

s

American National Standard are encouraged to investigate

the possibilityof

applying

the most recent edition of the standardndi ied below.

ANSVASME B1 20.1 1983 (R1

992),

Pipe Threau3,

eneral

Purpose inch)

3

Definitions

3.1

Threaded

coupling

A threaded coupling f o r intermediate metal conduit is an internally threaded t e e l cylinder for connecting two

sections

of intermediate metal conduit.

3.2 Elbow

andend

An

elbow

or

bend

s

a curved section of intermediate metal conduit threaded on each end.

3.3

Nipple

A

nipple

is

a straight section of intermediate metal conduit not more than

2

ft (0.61 m)

long

and threaded on

each end.

4 Units of measurement

he values

states

in inch-pound units are

to be

regarded as the standard. The metric equivalents may

be

approximate.

5

Generalequirements

5.1 Circolarcross section

intermediate metal conduit shall have a circular cross section sufficiently accurate to permit he cutting of

threads inaccordance with table.

5.2 Wall thickness

The wall thickness shall

e

in accordance with table.

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ANSI C80.6-1994

5.3

Interiorsurface

The

interior surface hall be

free

from injuriws defects.

5.4 Welding

hewelding

of

all seams shallbe continuous and

done

n a workmanlike manner.

5.5

Cleaning

Theconduit shall

be adequately cleaned before the application of the protective coating.he cleaning process

shall leave the exterior and interior surfacesf the conduit in such a

condition

that the protective coating shall

be firmly

adherent

and smooth.

5.6

Protectiveoating

5.6.1

The exterior

surface shall

be

thoroughly and evenly coated with metallic zinc

applied

directly to the

surface of theteel so hat metal-temetal contactnd galvanicprotedion

against

corrOsion are

provided.

5.6.2

The interior surface shall e protected by a zinc, enamel, or other suitableorrosion-resistant coating.

6

e t a i l e d

requirements

6.1 Zincoating

The zinc content of the coating on the outside surface shall be equivalent tominimum thicknessof

0 0008

n.

(0.02 mm.)

6.2

Enamelorequivalent oating

Enamel

or other equivalent protective coating shall havesmooth continuous surface. n

occasional

variation

due ouneven flow of coating

shall

be acceptable. The coatingshall not soften

at

a temperature of

120°F

49°C)

and

shall be sufficientlyelastic to meet the test described in.3.

6.3

Threading

and

chamfering

Each length of condut nipple, elbow, and bend shall be threaded on both ends, and each end

shall

be

chamfered

or

atherwise treated to remove

urrs

and

sharp

edges

Threads shall comply with the requirements of

.6.

I f threads are cut after the zinc coatinghas been applied,

the threads shall

be

treated with a protective coating to prevent conosion before installation.

This

treatment

shall not impair

electrical

continuity through couplings

r

fittings after installation.

6.4

kientification

Each

lengthof

conduit,

nipple,

elbow

and bend shall be -dentif with the manufacturer s name or trademark

and

the

letters

IMC

at

least 1/8 in.

3

mm) high, except that close threaded nipples need

ot

beso dentified.

6.5 Dimensions

The

dimensions of intermediate metal conduit shalle in accordance with table

.

6 6 Threads

The number of threads

e r

inch 25.4mm), and the length of the threaded portion

t

each end

of

each length of

conduit, nipple, elbow

and bend shall be as indicated in able 1, and shall conform o American National

standard Pipe Threads (inch)ANSVASME B1.20.1-1983

R-1992).

The perfect threadshall be tapered for its

entire length, and the taper shalle 3 4

¡Mt

62.5 mnVm).

6 7 Couplings

Couplingsshall comply with the following requirements:

2


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ANSI C80.6-1994

6.7.1 The exterior surface of couplings shall be protected by means of a zinc coating, which shall comply

with the requirements of

6.1.

The interior surface

hall be

treated to inhibit com>sion from takingp h rior to

6.7.2 Couplings shall beso made that all threadson he conduit will

be

covered when the couplings pulled

tight

on standard

conduit threads.

6.7.3

Bothends of the couplinghall be chamfered o prevent damage o the starting thread.

6.7.4 The outside diameter, length, pitch diameter, and chamfer diameter of couplings shall

be

as indicated

intable3.

6.75 Couplingsshall be straight apped.

6.7.6

Each length of finishedconduit

shall

haveone coupling attached.

6.8 Elbows, bends nd ipples

conduit

elbows, bends and nipples shall e made of a similar grade of

teel

to that employedn straight lengths

of

intermed hte metal

onduit,

and shallbe treated,

c o a t e d ,

threaded, and

natked

for identaication accordingo

the a p p l i i e requirements

or

intermediate

metal conduit

(zinc

coated).

No

bend

other than at the end curve of a gooseneck shall be sharper than

90

degrees. The sharpest

acceptable end curve is 135degrees. No bend shall be shallower than 15 degrees. The length

Ls

of the

straight portions at he ends of a bend and the radiusshall not be less than indicatedn table 4 for each

size of conduit. Figure illustrates the dimensions for conduit bends.

7

Test

procedures

7.1 Bendingroperties

7.1.1Ductility of steel

conduits shall

be

capable

of being bent cold into a quarter of a circle aroundmandrel, the radius of which

s

shown

in

table

4,

withcut developing cracksat any portion and without openinghe weld.

7.1.2

Ductilityof

zinccoating

The protective coatings used on the exterior and nterior surfaces of rigid

steel

conduit shall be sufficiently

elastic to prevent their cracking or flaking ff when a finished sample of trade size designator12 16 IMC) or

the smallest rade size manufactured is tested.

Test

shall be performed within 1 year after he ime of

manufacture, by bending12

16

IMC) into a alfcircle around a mandrel, the radius of which is shown in table

4 or by bending other trade size designators nto a quartercircle around a mandrel, the radius

of

which

s

shown in

table

4.

Compliance of trade size designators

1/2

16

IMC)

and 3/4 21 IMC) shall

be

determined by bending the

conduit

with a form

s

shown

in

fgure

1.

Compliance

of

trade sue designators larger than

/4

21

IMC) shall be

determined by bending the conduit with any suitable bending equipment.

7.2 Thickness of zinc oating

One of the following test methods shall

e

employed for measuring the thickness or extent

f

the external zinc

coating on conduit:

Magnetictest

Preece test (material that

will

withstand four 1-minute immersions shall

e

considered as meeting the

requirements of

6.1.

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ANSI

C80.6-1994

7.3

Qu a l ¡

of

enamel

coating for use on interiorsurfaces

Test

pieces

of uncoated sheet steel,

3

in. 76.2 mm) wide, 5 in.

127.00

mm) kmg, and

0.010

in.

(0.25

mm)

thid<, shall be cleaned with a suitable solvent to remove all grease and foreignmaterial. Each piece shall be

dipped into the namel that

is

used

for

coating thecondut and the coated test

ieces

shall

be

allowed toairdry

for

30

minutes before beinglaced in the baking oven. Eachiece shall be suspendedy means

of short

wires

in

he

baking

oven

and

the

samples

shall

be baked

o r

a period of

5

hours at the

m l

aking

temperature for

the

enamel

inquestion, except that

f

the normal

baking

temperature is

ess

than

275°F 135°C)

or if the enamel

is

regularly airdried, the oven temperature shalle maintainedat

275°F

to

302°F 135°C

to 1W C ) .

At

the end of the 5hour period, the test samples shallbe removed from the oven nd allowed to air-cool to

room

temperature.

Each

test piece

shall be

gripped

in

a vise . a n d then

bent

from theopposite side

back

and

forth ten times through an angle of

180

degrees, the radius of the bend

being 1/16

in.

(1.53

mm). When

so

tested, theenamel coating

on

he sample shallnot crack or flake.

8 Inspection

8.1 Placeof

inspection

All ests and nspections shall be made at he place of manufacture prior to shipment, unless otherwise

specified

and shall be

o

conducted

as not

to interfere with normal manufacturing processes.

8.2 Visual

inspection

Each length of

conduit

shall

be

examined visually, both on the exterior and interior surfaceso determine if the

produd is free from slivers, burrs, scale, or other similar njurious defects, and if coverage of the coating is

complete-

8 3 Retests

If any sample testedas prescribed in this specificationhould fail, two additional samples shallbe tested, both

of

which

shall comply with the requirementsf

this

specification.

9 Markingdentification

Each lengthof conduit, nipple, elbow and bend shall be identified with the manufacturer s name or trademark

and

he letters

MC

at least 143 in. 3mm) high, except that close threaded

ipples

need not

be so

dentified.

4


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A N S I C B O b 9 4 0 7 2 4 3 5 0 0 5 3 5 4 4 7 803

Trade

she

W

1R

34

1

1-114

1-1R

2

2-1R

3

81R

A

Threadl

h

14

14

11

11-1R

11-1R

11-1R

8

8

8

8

ANSI

C80.6-1994

Table 1- Dimensionsof threads for intermediate

metal

conduit

Womw

lnctFpound

UnHs

Lengthof

Thread

in.)

Pitch

Diamder

SItEndof

E 2

1ffecthre

innt

I*,

0 7584

1.73 1.30

.3344

1.a25

.8375

1.63

20

.3406

1.57 1.14

7195

1 o6

.76

2690

1.o3

.72

ml

1o1 0.71

W1

0.98

68

.2136

0.7955

.9677

0 78

53

Metric UnHs

I LerrsthofT

Pitch

Diameter

atEnd

of

Metric

-E

Trade-

Effeahre

a p e r a

eadd

DeSig-

mmhn

L,

16IMC

33.02

10.09403 IMC

31

75

7.4731

I M

30.48

4.851

8 IMC

285

9.0753

M

19.30

7 633l li2

3 IMC

18.29 45.621l IR

1 IMC

18.03

9.550

1-1R

5 MC

17.27

0.825t - lR

7 IMC

13.97

4.580 14 21MC

13.46

9.263

4

threadlength(U:-l

thre d

p i W l ~ : *1 b m i s I h e n l a% i m u m v r r o m t h e g a g e s .

Table

2

-Dimensionsof intermediate metal conduit

e& k

overail

L.

19.81

20.07

24.89

25.65

26.16

26 92

39.88

41.40

4267

43.94

Tradesbe Outside

Diameter

In.) Wall

Thkkness (in.)

ReferenœNominal

Desmator

Maximum

Minimum Maximum

Minimum

InMeDlameter

IR

0.m

0.810

0 085

0 070 0 659

34

1 a34

1o24 0 090

0 075 0 863

1

1.295

1.285 0.100

0 085 1.104

1-114

1 W

1

ex

0.105 0 085

1.448

1-112

1.890 1.875

0.110

0 090

1€W

2

2367 2352

0.115

0 095

2150

2-1R

2867

2847 0.160

0.140 2575

3 3.406

3.466

0.160 0.140 3.176

31R

3.981 3.961

0.160

0.140 3.671

4

4.476

4.456 0.160

0.140

4.166

Couphg

m)

16 IMC I 20.83 20.57 I 2.16 I 1.79 I 16.74 3.03

21 IMC

27 I M

35

IMC

41 IMC

53

MC

63 MC

78 IMC

91 IMC

103

IMC

26 26

3289

41.78

48.01

60.12

7282

88 54

101.12

113.69

47.62

88.04

100.61

113.18

229

2.54

2.67

279

292

4.06

4.06

4.06

4.06

1W

105.82

.56

93.25

.56

80.67 3.56

64 95

.56

54 59

.41

427429

36.7516

28.0716

21.M

3.03

3.02

3.02

3.02

3.02

3.01

3.01

3.00

3.00

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ANSI

C80.6-1994

Table

3

-Dimensions of couplings

Metric

Size

Deagnator

16

M

21IMC

27

I M

35 I M

41 IMC

53 I M

63

IMC

78

IMC

91

M

103

M

Tradesbe

DedQnatof

IR

W4

1

1-114

1-1R

2

2-1R

3

31R

outside

Diameter Minlmum

in.) i e n s t h

1 o10-5/8

125

1

525

1.889

2155

2650

3.250

3.870

4.500

4.875

1-41164

1-31/32

2-1/32

2-1/16

2-118

m l 6

35/16

3-13/32

3-3364

outside

Diameter Minimum

mm)

25.71.3

31.81.7

38.7 50.0

47.51.6

54.7 524

67.34.0

82.61 .O

98.3

84.1

114.3 86 5

123.8 89.3

cwtom ry n c h

pitch

I

Minlmum

0.801

1.011

1.267

1.612

1.852

2327

2806

3.431

3.931

4.431

Metricl

Pi¡

I

Minimum

20 35

25 68

32.18

4094

47.04

59.1 1

71.27

87.15

99.85

112.6

wnd Units

uneler

Maximum

0.814

1o24

1.283

1.628

1.868

2343

2828

3.453

3.953

4.453

Its

meter

Maximum

20 68

26.01

3259

41.35

47.45

59.51

71.83

87.71

1

OO4

113.1

chamiel

Minimum h)

0 798

1

o08

1.260

1€us

1

.a45

2320

2800

3.425

3.925

4.425

ch mfer

Minimum

20.27

25.60

32.00

40.77

46.86

58.93

71.12

87.00

99.70

11240

Maximum

in.)

0.838

1 o48

1.300

1.645

1.885

2360

2860

3.485

3.985

4.485

hmetef

Maximum

21.29

26 62

33.02

41.78

47.88

59.94

72.64

88 52

101.20

113.90

Table

4-

Minimumacceptabledimensions of

elbows

and other bends

Metricunits

tocenterof

- Lat-

Minimum

Radius R

M i n i m u m StreigM

Conduit mm)

End

mm)

101.60

38.10 114.30

38.10

85.73

06.40

8255

81 o0

79.38

30 20

76 20

66.70

50 80

41.30

50.80

09 55

50 80

84.15

47.63

46.05

6


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Figure 1-Conduit bends

7


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ANSI C80.6-1994