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Simple Conduit Fill Calculations / Reports
February 3, 2008, 06:50 PM Nate HoltThe product has some basic tools (been in there for a long time) that might help you group wire conductors into a conduit or wire-way run and then size it appropriately. A reporting tool lets you generate a simple project-wide conduit report.For example, let’s say the schematic shows a 50Hp motor, “MOT211” tied back to terminals in motor control center “MCC01A” through a safety switch “DS211A”. Elsewhere in the schematic is an aux contact from this safety switch tied in to the control circuit. The three phase wiring is drawn on layer “BLK_6_XHHW” which probably means black wire conductors, size 6AWG, insulation type “XHHW”.
How can AutoCAD Electrical help us calculate the appropriate conduit or wire-way size and ultimately give us a basic conduit/wiring report?
Setup
There is some initial setup required. This involves editing a couple ASCII text files – one to map each wire layer name on your drawings to a conductor diameter value. The other support file lists trade-size conduit and wire-way maximum fill cross-section values based upon your local electrical code.1. Wire diameter mapping fileThis is an ASCII text file, default name is default.wdw and an initial copy of this might be found in your AutoCAD Electrical "user" folder. Here is a modified version of this file set up for our example drawing set:
Each line of data is delimited into a maximum of three pieces (semi-colon delimited). The first gives the wire layer name, the second gives a text string that can be substituted for the layer name in various wire reports and for the color/gauge label command. The third entry gives the wire’s actual diameter value.
This file is used in other places in AutoCAD Electrical, but for conduit/wire-way sizing, the first and third data elements are what we are focusing on. You may already have a file like this on your system (in the "user" folder) but it may be lacking the third entry in each line. You’ll need to add in this conductor diameter data to enable AutoCAD Electrical to do any fill calculations. (Note: like many of the customizable support files in AutoCAD Electrical, this file can be made "project-specific" by copying it to a name "<project name>.wdw")So, in the motor example above, we have three conductors on layer BLK_6_XHHW. From the above table, AutoCAD Electrical now knows that each conductor’s diameter is 0.274 (pulled from manufacturer data or perhaps from an NEC Electrical Code table).2. Conduit / Wire-way Size TableThis second file’s default name is default.ww1 and is shown here (may be on your system under folder c:\program files\autodesk\acade 200x\support\) .
Each line is broken into two parts by a semi-colon delimiter. The first part gives the conduit or wire-way size and the second piece gives the maximum allowable cross-section fill. So, in the example file above, a ¾ inch conduit is 100% full when the sum of the conductor cross-sections reaches a value of 0.21.
Running the Conduit tagging/sizing utilityFirst of all, we need to turn on the “Conduit tagging” toolbar. It is not “on” by default. Go to the Project pull-down, select “Toolbars”, and select the conduit option.
A small, 5-button toolbar should show up somewhere on your screen.
Okay, we’re ready to go.
Let’s create a new drawing and add it to our project. This will be our conduit / interconnection diagram. Select the “Insert Footprint (Schematic List)” command on the first pull-down of the panel toolbar. Insert generic representations of the motor and the motor’s disconnect switch.Now draw a line or polyline between them to represent the conduit (or wire-way).
Next, select the right-hand button on the conduit toolbar. This will make sure that the project’s scratch database is up-to-date with schematic wire connection data. Now pick the left-hand button on the conduit toolbar. Pick on the line that represents the conduit and one more pick to identify where the little conduit marker tag is to be. Before you exit the command, it prompts to you select the device or devices that this conduit is going to run to. Pick on the motor symbol.
The Big Dialog
This Conduit Label dialog now pops open.
Two key things initially show up. First, in the bottom right hand part of the dialog is a list of all schematic wires that AutoCAD Electrical found going to motor MOT211.
And in the middle left-hand column is a listing off all the conduit entries you’ve set up in default.ww1 with the fill calculated for the sum of all of the listed wiring.
It looks like a ¾” conduit is large enough to handle the three # wires. But wait, let’s say we always run a green ground wire with all motor wiring. We may not show it on our schematics but it is in our installation specification for the contractor. Back at the dialog, select the “Spares” button and add in a #8 Green XHHW (highlight in the left-hand list and hit the “Add->” button to move a copy to the right-hand list).
Select OK. Note that the conduit fill window updated to take into account the extra added wire, and now a ¾” conduit is not quite large enough. Need to specify 1”. So, highlight the 1” entry and hit OK.
And here is our first conduit tag label. The wire information is stored right on the tag as invisible data.
Now let’s draw in a home run from this DS211A disconnect plus add in a second motor from our schematic. Here’s what we might lay out before attaching tags and sizing the conduits.
Now let’s do the run starting at the lower disconnect switch heading back to MCC. Pick the Insert/Edit Conduit Tag command again (left-most toolbar button) and pick on the line. Then pick on the DS211A representation. The big dialog displays all wires that tie into this disconnect switch. This includes two wires from a auxiliary contact in the control circuit and the three wires we already have going to the motor. Subtract out the direct to motor wires by doing a CTRL-select and hitting “Remove^”.
Add in the spare ground wire and look at the conduit fill values. Looks like 1” should be large enough for this segment.
Continuing on with the second motor...
And now, the final home run from the bottom tee-intersection back to MCC01A. This conduit segment will need all wires that show up in “C2” and in “C5”. So run the conduit tag insert and pick right on these two existing tags ( ! ). That’s it.
Conduit Report
To finish off, pick the 4th toolbar button and run a report. You may not get it to format exactly the way you’d like, but all the data is there. You can save it to an Excel spreadsheet and massage it as needed and then pop it back into your drawing as a table.
That's about it. Again, a simple set of tools. Take a look. Let us know where you'd like to see changes. For example, we''ve already received suggestions about flipping it to a "cable-centric" mode instead of its existing "conductor-centric" mode. And the wire assignments you make to the conduit tags are not currently set up to real-time update if the schematics change (arguments might be made both sides of that one). Anyway, let us know. Thanks! - Nate.
Comments
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February 14, 2008 12:48 PM Daryl Lee
I would truely love to see the conduit toolset's power increased. Conduit Reports/Wire Pull Reports take an enormous amount of time. I have tried to use the conduit tools on two different jobs and it is simply not worth the time. I'm not trying to be degrading but simply trying to convey my frustration. The tool I'm proposing is very similiar to the existing reporting tool; however, the existing reporting tool prompts you to select individual devices not an entire panel as the tool I'm suggesting would. To me the existing reporting tool is more of a Panduit wire tray manager than a conduit tool. Within a panel, one can select each device and run it through this wire tray. Conduits connect entire panels, motor control centers, field devices together. A panel may include hundreds of devices, such as terminal blocks, relays and contactors in them. Normally I have a plan view drawing of the plant spanning several buildings. On the plan view I will graphically locate each panel, operator station, motor, etc. The entire panel and all of its components are represented by a single rectangular box or block. Here is what I would like to see: 1. Add a tool that would add LOC and INST attributes to an object. These attributes will connect the schematic, panel design with the plan view of your site. The combination of LOC and INST uniquely identify each panel with all of the devices located within the panel. Connect each one of boxes or blocks with lines (conduit) showing the likely path the conduit will take over pipe bridges, etc. Each segment conduit segment would be given an identifier (conduit marker). Now add the attributes LOC and INST to rectangular box or block. Now you have conduits and conduit branches heading to each rectangular box or block with LOC, and INST attached to them. The LOC and INST values are already part of the database. At this point perform a database extraction of the conductors and cables and place in a table. The tool would prompt you to select each panel, operator station, motor, etc represented by the retangular boxes. Estimated cable lengths can be determined from the length of the lines connecting the panels. I guess off-page from-to connectors would be required and someway to include vertical distances. 2. Add Cross section tool. Add tool that allows user to select a conduit segment and perform a database extraction of the conductors and cables and place in a table for that one segment. 3. Only cable tags and conductors (not part of a cable) are listed in the report. Ask the question: "What object I'm I to pull through this conduit?" My reports typically show: CONDUIT ID, QTY - CABLE TYPE (OR) QTY - WIRE TYPE, CABLE ID (OR) WIRE NUMBER, FROM, TO, and EST. LENGTH. At this point in the job, the installer needs to know what cable/wire to pull, where to pull it to and how to label the ends so that the next guy can terminate it. I think that relatively little development could dramatically increase the usefulness of the conduit tool set. Thanks for listening.
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February 29, 2008 09:43 AM Nate Holt
Hi Daryl, thanks for the feedback. Let me digest this and get back to you. Thanks again. Nate.
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May 21, 2009 10:50 AM Charles Mongeau
Hi guys, great tool that helps me a lot to reduce engineering time but is there a way to put the (%full) in the conduit report? That would be great to have a small lisp with the user post that could add this information.
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July 28, 2009 03:18 PM Dan Hunsucker
Nate, have you seen any scenarios where this won't work? We've set up everything as it's supposed to, but it won't show the (%)'s. E 2008
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