Trade
Size
USA |
Trade
Size
Metric |
Inside
Diameter
Inches |
Inside
Diameter
Millimeters
|
Outside
Diameter
Inches |
Outside
Diameter
Millimeters
|
Fractional
Outside Diameter Inches |
Threads
per Inch
(NPT)
|
Size
Opening Needed Into Box |
Drill
for Tap
(NPT) |
| 1/2"
EMT |
16 |
0.622 |
15.80 |
0.706 |
17.93
|
|
|
7/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 1/2"
intermediate |
16 |
0.660 |
16.8 |
0.815 |
|
|
14 |
7/8" |
23/32"
or 3/4" |
| 1/2"
rigid |
16 |
0.622 |
15.80 |
0.840 |
21.34 |
27/32" |
14 |
7/8" |
23/32"
or 3/4" |
| 1/2"
flexible |
16 |
0.635 |
16.1 |
|
|
|
|
7/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
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| 3/4"EMT |
21 |
0.824 |
20.93 |
0.922 |
23.42 |
|
|
1
1/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 3/4"
intermediate |
21 |
0.864 |
21.9 |
1.029 |
|
|
14 |
1
1/8" |
59/64"
or 7/8" |
| 3/4"
rigid |
21 |
0.824 |
20.93 |
1.050 |
26.67 |
1
& 3/64" |
14 |
1
1/8" |
59/64"
or 7/8" |
| 3/4"
flexible |
21 |
0.824 |
20.9 |
|
|
|
|
1
1/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
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| 1"
EMT |
27 |
1.049 |
26.64 |
1.163 |
29.54 |
|
|
1
3/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 1"
intermediate |
27 |
1.120 |
28.1 |
1.290 |
|
|
11.5 |
1
3/8" |
1-5/32"or
1 1/8" |
| 1"
rigid |
27 |
1.049 |
26.64 |
1.315 |
33.4 |
1
& 5/16" |
11.5 |
1
3/8" |
1-5/32"
or 1 1/8" |
| 1"
flexible |
27 |
1.020 |
25.9 |
|
|
|
|
1
3/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| |
|
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| 1
1/4" EMT |
35 |
1.380 |
35.05 |
1.510 |
38.35 |
|
|
1
3/4"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 1
1/4" intermediate |
35 |
1.468 |
36.8 |
1.638 |
|
|
11.5 |
1
3/4" |
1-1/2" |
| 1
1/4" rigid |
35 |
1.380 |
35.05 |
1.660 |
42.16 |
1
& 21/32" |
11.5 |
1
3/4" |
1-1/2" |
| 1
1/4" flexible |
35 |
1.275 |
32.4 |
|
|
|
|
1
3/4"
(Fitting
opening) |
Tap
for fittings same as rigid |
| |
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| 1
1/2" EMT |
41 |
1.610 |
40.89 |
1.740 |
44.20 |
|
|
1
7/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 1
1/2" intermediate |
41 |
1.703 |
42.7 |
1.883 |
|
|
11.5 |
1
7/8" |
1-47/64"
or 1 3/4" |
| 1
1/2" rigid |
41 |
1.610 |
40.89 |
1.900 |
42.86 |
1
& 29/32" |
11.5 |
1
7/8" |
1-47/64"
or 1 3/4" |
| 1
1/2" flexible |
41 |
1.538 |
39.1 |
|
|
|
|
1
7/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
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| 2"
EMT |
53 |
2.067 |
52.50 |
2.197 |
55.80 |
|
|
2
1/2"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 2"
intermediate |
53 |
2.170 |
54.6 |
2.360 |
|
|
11.5 |
2
1/2" |
2-7/32"
or 2 1/4" |
| 2"
rigid |
53 |
2.067 |
52.50 |
2.375 |
60.33 |
2
& 3/8" |
11.5 |
2
1/2" |
2-7/32"
or 2 1/4" |
| 2"
flexible |
53 |
2.040 |
51.8 |
|
|
|
|
2
1/2"
(Fitting
opening) |
Tap
for fittings same as rigid |
| |
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| 2
1/2" EMT |
63 |
2.731 |
69.4 |
2.875 |
|
|
|
3"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 2
1/2" intermediate |
63 |
2.597 |
64.9 |
2.857 |
|
|
8 |
3" |
2-5/8" |
| 2
1/2" rigid |
63 |
2.469 |
63.2 |
2.875 |
73.03 |
2
& 7/8" |
8 |
3" |
2-5/8" |
| 2
1/2" flexible |
63 |
2.500 |
63.5 |
|
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|
|
3"
(Fitting
opening) |
Tap
for fittings same as rigid |
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| 3"
EMT |
78 |
3.356 |
85.24 |
3.500 |
88.90 |
|
|
3
5/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 3"
intermediate |
78 |
3.216 |
80.7 |
3.476 |
|
|
|
3
5/8" |
3-1/4" |
| 3"
rigid |
78 |
3.068 |
77.93 |
3.500 |
88.90 |
3
& 1/2" |
8 |
3
5/8" |
3-1/4" |
| 3"
flexible |
78 |
3.000 |
76.2 |
|
|
|
|
3
5/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| |
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| 3
1/2" EMT |
91 |
3.834 |
97.4 |
4.00 |
|
|
|
4
1/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 3
1/2" intermediate |
91 |
3.671 |
93.2 |
|
|
|
|
4
1/8" |
3-3/4" |
| 3
1/2" rigid |
91 |
3.548 |
90.12 |
4.00 |
101.6 |
4" |
8 |
4
1/8" |
3-3/4" |
| 3
1/2" flexible |
91 |
3.500 |
88.9 |
|
|
|
|
4
1/8"
(Fitting
opening) |
Tap
for fittings same as rigid |
| |
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| 4"
EMT |
103 |
4.334 |
110.08 |
4.500 |
114.30 |
|
|
4
1/2"
(Fitting
opening) |
Tap
for fittings same as rigid |
| 4"
intermediate |
103 |
4.166 |
105.4 |
|
|
4
& 1/2" |
|
4
1/2" |
4-1/4" |
| 4"
rigid |
103 |
4.026 |
102.26 |
4.500 |
114.30 |
|
8 |
4
1/2" |
4-1/4" |
| 4"
flexible |
103 |
4.000 |
101.6 |
|
|
|
|
4
1/2"
(Fitting
opening) |
Tap
for fittings same as rigid |
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