Determining Conduit Size -Cont.

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MIL-HDBK-1012/3
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EXAMPLE THREE (Continued)
D.
To determine the conduit size:
1.  Determine the outside diameter of the cables that will be
installed in the conduit.  For four-pair CAT 5 UTP assume 6.1 mm
(.24 in.).
Diameter  of Cables
in.
Number of Cables
2.  Use the chart below from NFPA 70 to identify appropriate
conduit size.
Number of Cables or Wires
Size
Cable/Wire Outside Diameter, mm/in.
3.3
4.6  5.6
6.1
7.4
7.9
9.4  13.5  15.8  17.8
mm
in.
(.13) (.18)(.22) (.24) (.29) (.31) (.37)(.53) (.62) (.70)
16
(1/2)
1
1
0
0
0
0
0
0
0
0
21
(3/4)
6
5
4
3
2
2
1
0
0
0
27
(1)
8
8
7
6
3
3
2
1
0
0
35
(1 1/4)
16
14
12
10
6
4
3
1
1
1
41
(1 1/2)
20
18
16
15
7
6
4
2
1
1
53
(2)
30
26
22
20
14
12
7
4
3
2
63
(2 1/2)
45
40
36
30
17
14
12
6
3
3
78
(3)
70
60
50
40
20
20
17
7
6
6
91
(3 1/2)
-
-
-
-
-
-
22
12
7
6
103
(4)
-
-
-
-
-
-
30
14
12
7
Note:
For 6.1 mm (.24 in.) diameter UTP cables nothing less
than 3/4 in. should be used.
Example:
If no. of cables
=
6
and all cable diameters =.24 in.
Conduit size =
1 in.
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36