WirePlan Pro

03 - Defining Wires and Conduit Sizing

Purpose: This document explains how to define electrical connections (wires) between nodes, edit their properties, and how WirePlan Pro automatically determines conduit sizes.

Adding Wires

Electrical connections, or wires, are fundamental to any electrical plan. WirePlan Pro offers several ways to add and manage these connections.

Manually Adding Wires (Dragging)

The most direct way to add a wire is by manually creating a connection between two nodes on the canvas:

  1. Initiate Drag: Press and hold the left mouse button over a node on the canvas. This node becomes the starting point for the wire.
  2. Drag to Target: While holding the mouse button, drag the cursor towards the desired end node. A temporary line will indicate the potential connection.
  3. Release Over Node: Release the mouse button when the cursor is over a different valid node.
  4. Wire Creation: If the drag is successful, a directed wire connection is created between the start and end nodes. By default, one wire with the currently set "Default Cable OD" will be added to this connection.
    • The application will add one wire to an existing connection if the connection is already defined. Otherwise, a new directed connection is established.
    • A status message will confirm the addition of the wire.

Using Wiring Topologies (Star, Ring, Bus) and "Default Cable OD"

WirePlan Pro can automatically generate wiring based on common topologies: Star, Ring, or Bus.

  1. Select Topology: Choose the desired topology ("Star", "Ring", or "Bus") from the "Wiring Topology" dropdown in the control panel.
  2. Set Default Cable OD: Ensure the "Default Cable OD (in)" field in the control panel is set to the desired outer diameter for the wires that will be automatically added. This value must be a positive number.
  3. Calculate Topology:
    • Star & Bus: Select a starting/hub node on the canvas first.
    • Click the "Add Topology" button.
  4. Wire Addition: The application will calculate the optimal wiring based on the selected topology and the existing conduit path. For each connection in the calculated topology, one wire of the "Default Cable OD" will be added. If a wire of that OD already exists on a connection, its quantity will be incremented.
    • The application status bar will provide feedback on the calculation and the number of wires added.

Selecting and Viewing Wiring Arrows

Editing Wires (OD and Quantity)

You can modify the properties (Outer Diameter and Quantity) of wires for any defined connection using the Wire Editor Dialog.

  1. Select a Wire: Click on the wiring arrow on the canvas that represents the connection you wish to edit.
  2. Open Editor:
    • Press the Enter key, OR
    • Right-click on the selected arrow and choose "Edit Wires" from the context menu.
  3. Wire Editor Dialog: A dialog window will appear, titled with the names of the connected nodes (e.g., "Edit Wires: NodeA --> NodeB").
    • The dialog displays a table of existing wires for that connection, showing "Cable OD (in)" and "Quantity" for each entry.
  4. Editing Entries:
    • Modify Existing: Double-click on a cell in the table to edit its OD or quantity. Input validation ensures ODs and quantities are positive numbers. ODs are typically formatted to four decimal places.
    • Add New OD: Click the "Add New OD" button. A new row will be added to the table with the "Default Cable OD" and a quantity of 1, which you can then edit.
    • Delete Entry: Select a row in the table and click the "Delete Selected" button. A confirmation prompt will appear before deletion.
  5. Save Changes:
    • After making your modifications, click the "Save" button.
    • The application will validate the entries (e.g., no duplicate ODs, positive values).
    • If valid, the wiring manager is updated with the new wire list for the connection.
    • Conduit sizes for affected 2D segments and vertical runs will be automatically recalculated.
    • The canvas will be redrawn to reflect any changes in conduit size annotations, and the total lengths display will be updated.
  6. Cancel: Click "Cancel" or press Escape to close the dialog without saving changes.

Deleting Wires

You can remove all wires associated with a specific directed connection.

  1. Select the Wire: Click on the wiring arrow on the canvas that you want to delete.
  2. Delete Action:
    • Press the Delete or Backspace key, OR
    • Right-click on the selected arrow and choose "Delete Wires" from the context menu.
  3. Confirmation: A confirmation dialog will appear asking if you want to delete all wires for the selected connection.
  4. Deletion Process:
    • If confirmed, the wiring manager updates the connection by setting its wire list to empty.
    • The visual arrow representation on the canvas is deleted.
    • The application state for the selected arrow is cleared.
    • Conduit sizes for affected 2D segments and vertical runs are automatically recalculated.
    • The canvas is redrawn, and total lengths are updated.
    • A status message confirms the deletion.

If all wires are removed from a connection (either through the Wire Editor by saving an empty list or by the "Delete Wires" action), the corresponding arrow will be removed from the canvas.

How Conduit Sizing Works

WirePlan Pro automatically calculates the minimum required conduit trade size for both 2D segments on the plan and vertical runs associated with node elevations.

Overview of NEC Fill Percentages Used

The conduit sizing calculations adhere to National Electrical Code (NEC) Chapter 9, Table 1 fill percentages:

The application calculates the total cross-sectional area of all wires passing through a conduit section. It then determines the minimum internal area the conduit must have based on the applicable fill percentage. This required area is then compared against the internal areas of standard conduit trade sizes (from NEC Chapter 9, Table 4 for the selected conduit type) to find the smallest suitable trade size.

Automatic Calculation for 2D Segments

For each straight segment of the calculated orthogonal conduit path on the 2D plan:

  1. Wire Aggregation: The application identifies all defined wires that are routed through that specific segment. This routing is based on the shortest path along the conduit graph between the wire's start and end nodes.
  2. Total Wire Area: The outer diameters (ODs) of all wires passing through the segment are collected. The sum of their individual cross-sectional areas (approximated as circular: $\pi \cdot (OD/2)^2$) is calculated.
  3. Size Determination: Based on the total wire area and the number of wires in that segment, the required NEC fill percentage is applied to determine the minimum internal conduit area needed.
  4. Conduit Selection: The application selects the smallest trade size of the chosen conduit type (RMC, IMC, or EMT) whose internal area meets or exceeds this calculated minimum.
  5. Storage: The calculated size string (e.g., "3/4") and the count of wires are stored for each 2D segment.

This recalculation occurs automatically when:

Automatic Calculation for Vertical Runs

For each node that has a defined elevation_delta greater than zero:

  1. Terminating Wires: The application identifies all wires that start or end at this node.
  2. Total Wire Area: The ODs of all these terminating wires are collected, and their total cross-sectional area is calculated.
  3. Size Determination: Similar to 2D segments, the NEC fill percentage based on the total number of terminating wires is used to find the minimum required internal conduit area.
  4. Conduit Selection: The smallest trade size of the chosen conduit type that meets this requirement is selected.
  5. Storage: The calculated size string for the vertical run at that node is stored.

Vertical conduit sizes are recalculated when:

Selecting Conduit Type (RMC, IMC, EMT)

Users can choose the type of conduit to be used for sizing calculations:

Understanding Conduit Size Annotations on the Canvas