Junction Box Designer
A free browser-based tool for turning structured cable and terminal data into a junction box or marshalling cabinet termination drawing, terminal schedule and commissioning site sheet.
Quick workflow
- 1. Name the JB. Add the tag, location, description, revision and notes.
- 2. Add cables. Enter incoming and outgoing cables, core counts, PE/screens and core details.
- 3. Generate the terminal box. The generator creates a sensible first pass; adjust terminals and rails where the real box differs.
- 4. Check the outputs. Review Diagram, Terminal schedule and Site sheet, then print or save as PDF.
Core details and panel references
Incoming cores can carry a function/type, panel or terminal reference, and description. Examples include 24VDC, Analog Input, Slot 8/2 or X10/2. The cable/core identity is kept for traceability while the useful engineering label is shown more prominently on the drawing.
Rails, spares and local JB functions
Add and rename terminal rails to match the physical JB. Unused multicore cores do not need a terminal. Incoming cores can also terminate on local/internal JB items with no outgoing field cable.
Saving projects
Projects are stored locally in the current browser. Use Export to create a JSON backup and Import to restore or move it to another device. Clearing browser storage can remove the locally saved project.
Install it like an app
Supported browsers can install Junction Box Designer so it opens in its own window and remains available from your desktop or home screen. On iPhone/iPad, use Safari’s Share menu and choose Add to Home Screen.