Menu
schema

Harness Builder - Schematic

straighten

Harness Builder - Layout

Component Creator

Cable Creator

1

Getting Started

Open the Harness Builder

To begin, click Builder → Harness Builder in the top navigation menu. This opens the interactive canvas where you will create your cable harness or assembly schematic.

  • The left sidebar displays your harness summary and bill of materials (BOM).
  • The center canvas is where you place components and make connections.
  • The right toolbar provides access to the Component Library, Wire Library, Cable Library, and PDF Page Configuration.
  • The top toolbar contains tools for saving, editing project details, exporting designs, and advanced features.
  • The bottom toolbar shows wire properties, swap status, or other context-specific details.
Splice interface showing BOM sidebar, canvas, and library buttons
Harness builder interface
Click to enlarge
2

Settings & Preferences

Configure Your Workspace

Access Settings settings from the top toolbar or context menu to customize your design environment.

grid_on Grid Settings
  • Toggle grid visibility for alignment reference.
  • Adjust grid spacing to suit your layout.
  • Enable snap-to-grid for precise placement.
tune Unit Preferences
  • Select wire diameter units: AWG or mm².
  • Select length units: Imperial (inches) or Metric (mm).
  • Units update automatically throughout the BOM and exports.
settings Tip: Settings are saved per user and apply to all of your projects
Opening and navigating settings window
Configure workspace settings and preferences
Click to enlarge
3

Harness Builder Interface

Toolbar & Controls

Familiarize yourself with the main toolbar and interface elements.

Main Toolbar
  • edit Edit: Project name, description, and notes.
  • folder_open Load: Open existing harness assemblies.
  • save Save: Auto-save indicator and manual save options.
  • undo redo Undo/Redo: Command history with hover previews.
  • link Bulk Connect: Connect multiple pins quickly.
  • share Share: Share a harness via public link.
  • file_download Export: PDF, SVG, PNG, and WireViz formats.
  • select_all Box Select: Select multiple items.
  • fit_screen Fit to View: Fit the design to the screen.
  • schema Schematic View: Switch to schematic wiring diagram.
  • straighten Layout View: Switch to physical layout view.
mouse Tip: Hover over toolbar buttons to view keyboard shortcuts.
warning Warning: A red disk icon indicates unsaved changes. Click Save to preserve your work.
Toolbar button interactions and hover states
Explore toolbar functions and hover states
Click to enlarge
4

Adding Components

Search and Select Components

Click the Component Library button on the right toolbar to open the search window. You can browse by category or shape, search by part number, or filter by specifications.

  • Browse by category: Circuit Breakers, Fuses, Connectors, Switches, etc.
  • Browse by shape: Circular, USB, D-Sub, Rectangular, Ferrule, Quick Disconnect, Ring Terminal, Terminal Block.
  • Search by part number, manufacturer, or keyword.
  • Filter results by pin count, voltage rating, or series.
  • Click add to add the selected component to your harness.
  • Click open_in_new to open the datasheet.
Component Categories & Shapes
Browse by Shape
  • Circular: Round multi-pin connectors
  • usbUSB: Universal Serial Bus connectors
  • D-Sub: D-subminiature connectors
  • Rectangular: Rectangular connectors
  • Ferrule: Wire-end sleeve terminals
  • Quick Disconnect: Spade and blade terminals
  • Ring Terminal: Ring and lug terminals
  • Terminal Block: Barrier strip connectors
Browse by Category
  • Circuit Breakers: Overcurrent protection
  • Fuses: One-time overcurrent protection
  • radio_button_checkedPush Buttons: Momentary and latching controls
  • toggle_onSwitches: Manual control elements
  • Relays: Electromechanical switching
  • electrical_servicesContactors: Heavy-duty power switching
  • scheduleTimers: Time-delay control relays
  • powerPower Supplies: Voltage conversion modules
  • Motors: Electric motor components
  • airFans: Cooling and ventilation
  • memoryPCBs: Printed circuit boards
  • Resistors: Fixed and variable resistors
  • Capacitors: Energy storage components
  • Diodes: Rectifiers and semiconductor switches
  • Inductors: Coils and chokes
  • Transformers: Voltage transformers
  • Inverters: DC-to-AC conversion
  • call_splitSplices: Wire joining and connections
  • battery_charging_fullBatteries: Power cells and packs
  • Solar Cells: Photovoltaic modules
  • categoryOther: Miscellaneous components
lightbulb Tip: Try searching for "JST XH", "Molex MicroFit", "Samtec Tiger Eye", or specific part numbers
Adding components from the Component Library window
Search and add components to your harness
Click to enlarge
Component block icon for the added component
Component block icon for the added component
Click to enlarge
5

Creating Generic Components

Build Custom Components

When a component isn't available in the library, you can create a generic component with custom pin counts, shapes, and properties.

Creating a Generic Component
  • Click the Component Library button on the right toolbar.
  • Click the add Create button at the top right to enter generic creation mode.
  • Step 1: Select a category (Connector, Circuit Breaker, Fuse, etc.)
  • Step 2: Choose a visual template from the grid, or upload custom SVG graphics
  • Step 3: Fill in component details:
    • MPN: Manufacturer Part Number (required)
    • Manufacturer: Component manufacturer name
    • Description: Brief description of the component
    • Positions: Number of pins/contacts
    • Datasheet URL: Link to manufacturer documentation
    • Image URL: Link to product image
  • Check "Make public" to share your component with other users.
  • Click Create to add the generic component to your harness.
auto_fix_high Auto-populate: Click the magic wand icon auto_fix_high next to the MPN field to automatically fetch manufacturer, description, datasheet URL, image, and category-specific specifications from DigiKey.
lightbulb Tip: Generic components support all standard features including pin mapping, signal names, and connection management.
Generic component block example
Generic component blocks support all standard features
Click to enlarge
6

Positioning Components

Arrange Your Layout

Splice automatically routes wires and cable cores for optimal visibility. For clean layouts, position connector blocks, cable blocks, and wire bundle blocks in a logical pattern relative to each other.

Single Component Movement
  • Drag components using the handle at the top-left corner.
  • Use zoom controls for precision.
  • Enable snap-to-grid for alignment.
Multi-Select Operations
  • Box Select: Click and drag to select multiple items.
  • Ctrl+Click: Add individual items to your selection.
  • Group Move: Drag any selected item to move the group.
  • Group Delete: Press Delete to remove all selected items.
Copy & Paste
  • Ctrl+C: Copy selected components
  • Ctrl+V: Paste to clone a component or cable
Multi-select and group operations
Multi-select, move, and delete operations
Click to enlarge
7

Component Blocks

Splice uses three visual block types—Component Blocks, Wire Bundle Blocks, and Cable Blocks—each with unique characteristics and controls.

Component Block Header
  • Designator: Auto-generated ID (X1, CB1, F1, SW1, etc.)
  • Part Number: Manufacturer and MPN
  • Type Description: Shape and gender designation, or category specific data
  • Drag Handle: Gray square (top-left) for moving components
Designator Prefixes
CB1 Circuit Breakers
F1 Fuses
radio_button_checkedS1 Push Buttons
toggle_onSW1 Switches
K1 Relays
electrical_servicesKM1 Contactors
scheduleKT1 Timers
powerPS1 Power Supplies
M1 Motors
airFAN1 Fans
memoryPCB1 PCBs
R1 Resistors
C1 Capacitors
D1 Diodes
L1 Inductors
T1 Transformers
INV1 Inverters
battery_charging_fullBAT1 Batteries
PV1 Solar Cells
call_splitSP1 Splices
X1 Connectors (default)
C1 Cables
Pin Section
  • Pin Numbers: Default numbering, customizable with pin mapping.
  • Signal Names: Editable labels for each pin.
  • Connection Circles: Visual connection points.
Connector block exactly as it appears in Splice
Click to enlarge
7a

Wire Bundles

Bundle Header
  • Bundle ID: Displays connected endpoints (e.g., Bundle X1|X2).
  • Length: User-defined wire bundle length
Wire Information Format
  • Format: "From | Signal | Gauge | Stranding | Color | To"
  • Example: "X1.1 | TX | 22 AWG | 7/30 | blue | X2.1"
  • Connection Points: Shows specific pin assignments
Wire bundle block exactly as it appears in Splice
Click to enlarge
7b

Cable Blocks

Cable Header
  • Cable ID: Auto-numbered (C1, C2, etc.).
  • Specifications: Manufacturer, part number, and length.
  • Shield Indicator: Yellow "Shld." badge if shielded.
  • Jacket Color: Visual indicator of cable jacket color.
Core Structure
  • Core Numbers: Sequential conductor identification (1, 2, 3, 4...)
  • Color Coding: Individual core colors for identification
  • Core Numbers in Circles: Quick visual reference
  • Shield Connection: Separate row for shield connection
Cable block exactly as it appears in Splice
Click to enlarge
8

Making Connections

Connect Pins with Wires

Use the Wire Library to select wires and create connections between component pins.

Basic Connection Process
  • Click the Wire Library button on the right toolbar.
  • Select a wire type from the library.
  • Click the first pin to connect.
  • Click the second pin to complete the connection.
  • The wire will auto-route between the pins.
Managing Connections
  • Click a connection to open the property editor at the bottom of the canvas.
  • Edit wire properties such as color or gauge without breaking the connection.
Bulk Editing Wires
  • Select a wire bundle in the left sidebar or Ctrl+Click multiple wires on the canvas.
  • Edit all selected wire properties as a group in the property editor.
1
Select wire
2
Click first pin
3
Click second pin
4
Connected!
Basic wire connection workflow
Create wire connections between pins
Click to enlarge
Modifying and managing connections
Modify and manage existing connections
Click to enlarge
9

Wire Routing & Waypoints

Control Wire Paths

Wires and cable cores include a vertical jog between endpoints. This position is calculated automatically but can be adjusted manually for improved clarity.

Auto-Route Bundles or Cables
  • Click the header of a wire bundle or cable block to reveal controls.
  • Click Auto-Route to apply automatic routing.
  • Click Fix Waypoints to lock the jog position.
Manually Adjust a Single Wire
  • Select the wire by clicking on it.
  • Drag along its path to create or move waypoints.
  • Adjust each waypoint handle for precise routing.
Move All Wires on a Block Side
  • Click the block header to reveal controls.
  • Use the first_page or last_page buttons at left and right of the block to shift all wires on that side.
Manual single wire waypoint adjustment
Adjust individual wire routing paths
Click to enlarge
Group waypoint and bundle management
Move wire bundles and group waypoints
Click to enlarge
10

Signal Names

Label and Configure Connections

Assign signal names to improve documentation and clarity in manufacturing.

Editing Signal Names
  • Click the header of a connector block to reveal controls.
  • Click Edit to open the Edit Signals dialog.
  • Enter descriptive names such as PWR_12V, GND, CAN_H.
  • Signal names will appear in the BOM and exported documents.
Signal name editing and wire properties
Edit signal names and wire properties
Click to enlarge
11

Connection Management

Move or Swap Existing Connections

Moving a Connection
  • Click the occupied pin to open the Connection Management dialog.
  • Select the wire or cable core in the Move/Swap/Twist Connections list.
  • Click the target pin to move the wire.
  • If the target pin is occupied, choose Move Here to keep its existing connection.
Swapping Two Connections
  • Click the occupied pin to open the Connection Management dialog.
  • Select the wire or cable core in the Move/Swap/Twist Connections list.
  • Click another occupied pin to swap with.
  • Select Swap to complete the change.
Moving and swapping wire connections
Move and swap connections for design optimization
Click to enlarge
12

Adding Cables

Add Multi-Core Cables

  • Click the Cable Library button on the right toolbar.
  • Search by cable type, gauge, or conductor count.
  • Click add to add the cable to your harness.
Adding cables from the library
Add multi-core cables to your design
Click to enlarge
13

Creating Generic Cables

Build Custom Cables

When a specific cable isn't in the library, you can create a generic cable with custom conductor counts, gauges, colors, and specifications.

Creating a Generic Cable
  • Click the Cable Library button on the right toolbar.
  • Click the add Create button at the top right to enter generic creation mode.
  • Fill in basic properties:
    • Part Number: Cable part number
    • Manufacturer: Cable manufacturer
    • Description: Cable description
  • Configure cable specifications:
    • Number of Cores: Total conductor count
    • Shielded: Yes/No shield option
    • Shield Type: Foil, Braid, or Spiral
    • Jacket Color: Outer jacket color
  • Cable Cores: Configure each individual core
    • Bulk Edit: Set AWG, stranding, color, and stripe for all cores at once
    • Individual Core Config: Customize designation, AWG, stranding, color, and stripe per core
    • Live Preview: See cross-section diagram as you build
  • Save as custom cable: Optional checkbox to save to your library for reuse
  • Click add Create to add the generic cable to your harness (and optionally to your library).
When to Use Generic Cables
  • Custom multi-conductor cables not in the standard library
  • Specialized industrial or military-spec cables
  • Custom color coding requirements
  • Prototype harnesses with unique cable specifications
lightbulb Tip: Check the "Save as custom cable to library" checkbox to add it to your library with your preferred conductor color schemes for reuse in future projects. Cable length is set when you add the cable to your harness.
Generic cable block example
Generic cable blocks with custom specifications
Click to enlarge
14

Bundle Labels

Add Visual Labels to Connectors

Bundle labels help identify harness sections, add assembly instructions, or mark important locations on your design.

Adding Labels
  • Click a connector on the canvas to show its toolbar.
  • Click label label icon in the toolbar.
  • Click Add Label to create a new label.
  • Enter the label text and customize the appearance.
Label Properties
  • Label Text: The text displayed on the label tag.
  • Background Color: The fill color of the label.
  • Text Color: The color of the label text.
  • Width: Label width in millimeters (for heat-shrink export).
Wire Association
  • Labels can be associated with specific wire bundles.
  • Associated labels appear in wire label exports.
  • Use the dropdown to select which bundle a label belongs to.
Wire Label Export
  • Export labels as a CSV file for label printing.
  • Includes label text, dimensions, and wire associations.
  • Compatible with Brady, Brother, and other label printers.
Adding bundle labels to connectors
Add labels to connectors via the toolbar
Click to enlarge
Configuring wire labels for export
Configure and export wire labels
Click to enlarge
15

Bulk Operations

Use the Bulk Connect Tool

  • Click link Bulk Connect in the top toolbar.
  • Select two components (or a component and a cable) to connect.
  • Choose a connection pattern:
    • Straight-Through: 1→1, 2→2, 3→3...
    • Crossover: 1→N, 2→N-1, 3→N-2...
    • Custom: Define your own pin mapping
  • Set wire properties for all connections.
  • Preview before applying.
Bulk connect tool workflow
Create multiple connections with bulk connect
Click to enlarge

Bulk Property Editor

Edit properties of multiple components, wires, or cables in a spreadsheet-like interface.

  • Press E or click edit_note Bulk Editor in the floating panel menu.
  • Components Tab: Edit instance IDs, descriptions, and renumber components sequentially.
  • Wires Tab: Edit wire color, AWG, length, and toggle bundle visibility for multiple wires at once.
  • Cables Tab: Edit cable properties and lengths in bulk.
  • Changes are applied with undo/redo support.

Collapse/Expand Components

Simplify complex diagrams by hiding unused pins and cable cores.

  • Right-click on the canvas background to access the context menu.
  • Collapse All: Hides all empty/unused pins on connectors and cores on cables.
  • Expand All: Shows all pins and cores, including unused ones.
  • You can also collapse/expand individual connectors via their right-click menu.

Bundle Visibility Controls

Control the visibility of wire bundle blocks without affecting the wire paths themselves.

  • Right-click on a bundle and select Minimize Bundle or Expand Bundle.
  • Use Minimize All Bundles or Expand All Bundles from the canvas context menu.
  • When minimized, wire paths remain visible and interactive—only the bundle block is hidden.
  • Toggle Compact View on bundles to show a condensed version with less detail.
Bulk property editor for editing multiple items
Edit multiple components, wires, or cables at once
Click to enlarge
Minimize and expand bundle visibility
Minimize bundles to simplify the diagram view
Click to enlarge
16

Export & Documentation

Create Manufacturing Documentation

PDF Multi-Page Export
  • Click the PDF Pages button on the right toolbar.
  • Add multiple pages with custom sizes (A2, A3, A4, Letter, or custom dimensions).
  • Position and scale page frames over your design.
  • Export as multi-page engineering drawings with BOM, Connection Table, and Cut List.
BOM Placement Options
  • Toggle "BOM on separate page" in the PDF Pages panel to control BOM placement.
  • When enabled (default): BOM renders on dedicated page(s) after the diagram, followed by Connection Table and Cut List.
  • When disabled: BOM overlays on each diagram page corner.
Connection Table Export
  • Detailed wire-by-wire connection information grouped by bundle.
  • Shows from/to pins, signal labels, wire color, AWG, and length.
  • Included automatically in multi-page PDF exports.
  • Available via Download & Upload > Connection Table.
Cut List Export
  • Consolidated wire requirements with total length calculations.
  • Groups wires by MPN and manufacturer.
  • Shows length distribution (e.g., "3 x 200mm, 2 x 350mm").
  • Export as CSV, Excel (XLSX), or PDF.
  • Available via Download & Upload > Cut List.
Available Export Formats
  • picture_as_pdf PDF: Engineering drawings with BOM, Connection Table, and Cut List.
  • code SVG: Scalable vector graphics for print or web.
  • image PNG: High-resolution raster images.
  • description WireViz YAML: For use with WireViz visualization tool.
  • data_object JSON: Machine-readable project data.
  • table_chart Cut List: CSV, Excel, or PDF with wire requirements.
  • list_alt Connection Table: PDF with wire-by-wire connection details.
Project Management
  • save Save: Save your harness design to the cloud.
  • folder_open Load: Load existing designs from your account.
  • share Share: Create a public link to share your design.
  • history Revisions: Access previous versions of your design.
PDF export and documentation workflow
Configure and export multi-page documentation
Click to enlarge