Conduit and Media Twist™
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`14 Oct 1997 - 8 Feb 2001
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`jhttp://www.belden.com:80/products/tbcondmthtm
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`Page 1 of 3
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`Sen
`
`Technical Papers
`
`Conduit and MediaTwist™
`
`UPDATED 8/25/97
`
`by Stephen H. Dampen
`Technology Development Manager
`Belden Wire & Cable Company
`
`ABSTRACT
`
`This white paper deals with using MediaTwist in conduit. As MediaTwist is not round but crescent-shaped, this has led to
`some confusion about conduit fill percentages and determining the space available for other non-MediaTwist Cables.
`
`MEDIATWIST AREA
`
`As this concerns conduit, no plenum-rated cables were considered and only non-plenum cables are mentioned below. Since
`MediaTwist is not circular, the area cannot be determined by standard geometry. The area of a single four-pair non-plenum
`MediaTwist cable is 0.0441 square inches. This leads to standard conduit fill in the following chart:
`
`MediaTwist Area and Conduit Fill
`
`Conduit
`Size
`
`Equivalent
`Square Inches
`
`30%
`fill
`
`Number of
`MediaTwist
`Cables
`
`40%
`fill
`
`Number of
`MediaTwist
`Cables
`
`2
`
`1
`
`.304
`
`.533
`
`.864
`
`1.496
`
`.101
`
`.16
`
`.259
`
`.449
`
`2
`
`3
`
`5
`
`.122
`
`.213
`
`.346
`
`.598
`
`2
`
`4
`
`7
`
`50%
`fill
`
`.152
`
`.267
`
`.432
`
`.748
`
`Number of
`MediaTwist
`Cables
`
`3
`
`6
`
`9
`
`16
`
`13
`
`1 2
`
`2
`
`22
`
`3
`
`32
`
`4
`
`2.036
`
`3.356
`
`5.858
`
`8.846
`
`11.545
`
`14.753
`
`.611
`
`1.01
`
`1.76
`
`2.65
`
`3.46
`
`4.43
`
`10
`
`13
`
`22
`
`39
`
`60
`
`78
`
`100
`
`.814
`
`1.34
`
`2.34
`
`3.54
`
`4.62
`
`5.09
`
`13
`
`18
`
`30
`
`53
`
`80
`
`112
`
`133
`
`1.02
`
`1.68
`
`2.93
`
`4.42
`
`5.77
`
`7.38
`
`23
`
`38
`
`66
`
`100
`
`130
`
`167
`
`https://web.archive.org/web/! 9971014055920/http://www.belden.com:80/products/tbcond... 6/21/2017
`
`Juniper Ex 1031 - 1
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`IPR2016-01397
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`

`

`Conduit and Media Twist™
`
`Page 2 of 3
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`[rhAtTA,,°fT'Tt.3"^ard (NEC) suggest[j|ti^i4id^gc^lie^{alGiiS§^B^resentMto show how mugTqifference reducing =
`I01 IWWIfrtfllOnllffi;andard number would make. For other types of conduit (nonmetallic, flexible, liquidtight etc.) consult tht
`•ag^^^O jo 70-882 (Chapter 9, Table 4).
`I
`
`,
`
`MIX AND MATCH
`
`Combining MediaTwist with other cables is not as difficult as one might imagine. You simply have to determine the area of
`the conduit and add up the area of every cable. Here's an example from an actual construction site.
`
`THE PROBLEM: The contractor was wiring up a hotel. He wanted to run eight 4-pair MediaTwist and he wanted to know
`what other UTP data/phone cable he could run with it. He was limited to 40% fill of a 1 %" conduit. 16 MediaTwists would
`be .706 fill or 47%, so he couldn't run all MediaTwist. He had to run at least two pair to the same eight destination, meaning
`he wanted to add eight 2-pair or eight 4-pair cables to the eight MediaTwist cables.
`
`Here's how it ended up:
`
`1 VA" conduit = 1.5 sq. inches.
`
`40% fill = 0.598 sq. inches
`
`8 MediaTwists = 8 X .0441 = .352 sq. inches
`
`Space remaining = .246 sq. inches.
`
`Possible cables are listed below. Information in the first four columns is available from the Belden catalog. The fifth column
`can be determined by using the "n rr formula or by taking the O.D., multiplying it by itself and then by 0.7854 which will
`give you the area .
`
`Below are some typical cables with the area of each. The last column is the area in the previous column multiplied by eight.
`In our example, where the space remaining is .246 sq. in., any total in the last column past .246 exceeds 40% fill.
`
`Tynt
`Category 3
`Category 3
`Category 5
`Category 5
`DataTwist 350
`
`Belden Part # Pairs O.D. Cable Area 8 X cable am:
`.140
`1227A1
`2-pair
`.0154
`.112
`1229A1
`.170
`.0227
`.182
`4-pair
`15 88A
`.183
`.0263
`.210
`2-pair
`.214
`.288
`.036
`1583A
`4-pair
`.251
`.200
`.0314
`
`1700A
`
`4-pair
`
`The last two cables do not pass the .246 area which remains. However, the contractor ended up using DataTwist 350. The
`total fill was .352 (8 MediaTwist) plus .251 (8 DataTwist 350) for a total of .603 square inches. This gave a conduit fill
`of .603/1.496 = 40.3%, so close to 40 % that it could be ignored. The contractor "future-proofed" the installation. If he had
`installed Category 3, it would not perform much past 1 ObaseT or similar performance. DataTwist 350 opened up his "low
`quality" portion to future upgrades without the need for rewiring.
`
`NEC CONSIDERATIONS
`
`There has been considerable discussion about the shape of MediaTwist and the NEC regarding its shape. In the NEC Code
`book Chapter 9, Table 1 (Page 70-879), Note 5 states:
`
`For conductors not included in Chapter 9, such as multiconductor, the
`actual dimension shall be used.
`
`Further, in Note 9, it states
`
`A multiconductor cable of two or more conductors, shall be treated as a
`single conductor for calculating percentage of conduit fill area. For cables
`
`https://web.archive.org/web/19971014055920/http://www.belden.com:80/products/tbcond... 6/21/2017
`
`Juniper Ex 1031 - 2
`Juniper v Chrimar
`IPR2016-01397
`
`

`

`Conduit and Media Twist™
`
`Page 3 of 3
`
`ft; t'« ft t>|
`1111111 ^
`
`that have
`be based on using the major diameter of the ellipse as a circle diameter.
`
`instead So the stated cross-sectional area of MediaTwist (0.0441 sq. in.) can be used for conduit fill calculations.
`
`I ciitrft t< 1 c-WW'y 1 i mi* 1 *mi>
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`
`Copyright © 1997 Belden Wire & Cable Company
`
`https://web.archive.org/web/! 9971 Of 4055920/http://www.belden.com:80/products/tbcond..
`
`6/21/2017
`
`Juniper Ex 1031 - 3
`Juniper v Chrimar
`IPR2016-01397
`
`