ConduitPro Design

ConduitPro Design

The ConduitPro is a Microsoft© hosted Excel™ spreadsheet program that will assist anyone interested in determining conduit fill capacity, bend radius and maximum pull tensions for horizontal communications cabling. The ConduitPro workbook incorporates eight (8) topic-planning sheets: EIA-Fill, Peter’s-Fill, Peter's Fill Item#1, Peter's Conduit Fills, Circle Packing, Square Packing, Fill-Pull-Bend and Conduit Sizes. 1. The EIA-Fill Sheet can be used to determine conduit fill and bend radius per ANSI/TIA/EIA-569 Standard. The user may designate cable internal diameter and quantity of cables in order to calculate the minimum conduit size per standard. In addition, conduit minimum bend radius can be calculated for installation.

In the above example is Item 1, a 2-1/2" EMT conduit would be required to install 37 - 0.24" OD cables and still be "to code".

Item 2 allows ConduitPro to calculate how many cables will fit into an existing standard 1-1/4" EMT conduit.

Item 3 below will use the fill parameters to calculate any size conduit (ID known). The Jam Ratio is calculated to help you determine possible install problems if the conduit size ratio to cable count-OD is less than 3.0.

The minimum bend radius can be calculated for any size conduit.

2. The Peter’s-Fill Sheet can be used to determine standard conduit fill and bend radius per the National Electric Code (NEC) and general code guidelines. The user may designate cable internal diameters of up to four (4) different cables [SPECIAL NOTE: We just have added a special sheet to handle up to ten (10) different cables] and the quantity of each cable in order to calculate the minimum conduit size per standard. In addition, a Jam Ratio (difference between cable OD and conduit ID) is provided that lists the potential for 3 or more cables to jam on bends during the installation process. The user may modify all parameters on all sheets that are color-coded green (safe to use).

Question: What size conduit is required to house (37-0.24" cables, 41-0.15" cables, 44-0.26" cables and 5-0.25" cables? Answer: a 4" EMT. In fact, you can still add an additional 18-0.25" cables and still be code compliant for the 4" conduit.

Calculations used in Peter's-Fill Sheet are more exact than the ANSI/TIA/EIA-569 Standard; which does major rounding of the area and Pi.

Item 2 will allow you to calculate how many cable will fit into a General EMT trade size conduit.
Peter's Fill Item 2

NEC calculations are rounded significantly

Item 3 of Peter's Fill will allow calculations for any size ID conduit

3. Peter's Conduit Fills - has 2 sets of 5 conduit layouts to determine: Conduit capacity based on cable OD and the cable count for up to 10 separate conduits and will determine size and fill capacity of each conduit. The third set of 5 conduit layouts determines conduit internal diameter. This overall sheet was a late addition suggested by a contractor. They installs cabling in conduit and wanted an easy way to determine conduit sizing quickly. As in most cases, cabling additions and some subtractions are the modus-operandi of any installation; this sheet will easily calculate conduit sizes based on cable outside diameter and count.

Question: Cable OD is 0.125", Conduit A has 71 cables, Conduit B has 56, Conduit C=36, Conduit D=31 and Conduit E=1. What are the conduit sizes and percent fills?
Answer: ConduitPro Item 1 calculates: Conduit A=2"(26% fill), Conduit B=1-1/2"(34% fill), C=1-1/4"(30%), D=1-1/4"(26%) and Conduit E=1/2"(5% filled). Also, ConduitPro determines you are using 15 cables in the junction box between Conduits A and B, 20 between B-C, 5 between Conduits C-D and 30 between D-E

Item 3 determines the minimum cable internal diameter that will support the cable count and still be "Standards compatible".

Question: What are the desired conduit ID's of cables as follows: Conduit "K" has 15 cables, Conduit "L" has 20 cables, "M"-5, "N"-30 and "O" - 1?

Answer: Conduit "K" ID must be at least 0.765465543", Conduit "L" - 0.883883476", Conduit "M" - 0.441941736", Conduit "N" - 1.082531755" and Conduit "O" - .1717100703"

4. The Circle Sheet has three (3) special subgroups to determine:
Circle Sheet Item 1: Maximum Cable Count in a conduit based on density packing (100% or similar to NASA space packing).

Circle Sheet Item 2: Calculate the diameter of a tangent cable that will fit between two (2) tangent cables and a surface.

ConduitPro Item 2 - 2 cables in a conduit

Circle Sheet Item 3: To calculate what size conduit is required to fit 3 cables of varying outside diameters (OD)

ConduitPro Item 3 - 3 cables in a conduit

5. The Square Sheet Item 1 has three (3) special subgroups similar to the Circle Sheet:

Square Sheet Item 2: To calculate what size cable will fit between 2 cables of known diameter (all touching each other and a surface)

ConduitPro Item 2 - tangent circles to a line

Square Sheet Item 3: To calculate the outside diameter (Cable B) of the cable that will fit in a square corner between a know diameter cable (Cable A = 3") touching the corner edges. Answer- 1/2 " cable.

ConduitPro Item 3 - tangent circles to each other and a corner

6. The Fill-Pull-Bend Sheet also has three (3) special subgroups to determine:
a. The number of cables that will fit into a cable-management trough

b. The maximum allowable pulling tension of a solid copper conductor

ConduitPro Max Pull based on conductor size

c. The bend radius of communications cable. It is possible to group like conductors in order to calculate the straight-run pull tension of various cables such as a 50-pair 22 AWG cable.
In addition, the minimum cable bend radius “Rule of Thumb” is listed for user perusal.

7. The Conduit Size Sheet lists standard conduit sizes, ranging from ½” to 6”. Standard conduit like EMT, GRC, PVC, EB and DB are listed for perusal.

Disclaimer: In all cases, contact the cable/conduit vendor to ascertain exact dimensions and design information. The manufacture's specifications and recommendations supercedes any CablePro calculations.