Junction box schedule Excel template.
The wiring termination register inside every field junction box, marshalling cabinet and panel, one row per terminal.
- AJB Tag
- BTerminal Strip
- CTerminal Number
- DWire Number
- EWire Color
- FCable Number
- GInstrument Tag
- HSignal ClassAIAODIDON/A
- IFrom
- JTo
- KNotes
Frozen header, auto-filter on every column, 48 blank rows ready to fill. No macros.
Every column, defined.
Eleven columns, in the order the sheet carries them. Signal class is the only dropdown; wire colour stays free text, so IEC and North American codes both fit.
| Col | Column | What goes in it |
|---|---|---|
| A | JB Tag | Junction box tag (JB-101, MJB-3) |
| B | Terminal Strip | Strip identifier (TS-1, TB-A) |
| C | Terminal Number | Terminal position (1, 2, 17) |
| D | Wire Number | Wire tag (1+, 1-, S) |
| E | Wire Color | IEC 60757 or project colour code |
| F | Cable Number | Cable landing on the terminal (C-101-001) |
| G | Instrument Tag | Instrument the wire serves |
| H | Signal Class | AI, AO, DI, DO, or N/A |
| I | From | Origin (instrument terminal or upstream JB) |
| J | To | Destination (DCS, MCC, downstream device) |
| K | Notes | Spare, shield, intrinsic safety, IS barrier |
Where each column comes from.
A JB schedule is assembled from several documents. The tag and cable columns can be filled once the P&IDs and the cable schedule are issued; the terminal columns wait for the wiring drawings.
| Columns | Usually taken from |
|---|---|
| Instrument Tag, Signal Class | The P&ID and the I/O list |
| Cable Number | The cable schedule |
| JB Tag | The cable schedule, or the instrument location plan |
| Terminal Strip, Terminal Number, Wire Number, Wire Color | The junction box wiring drawings |
| From, To | The loop diagram |
| Notes | Spares, shields and intrinsic safety barriers, from the panel design |
Common questions
What is a junction box schedule?
A junction box schedule (JB schedule) is the wiring termination register inside every field junction box, marshalling cabinet, or panel. Each row records one terminal: the JB tag, the terminal strip and number, the wire number and colour, the cable that lands on it, the instrument it serves, the signal class, and the from / to endpoints. The schedule is handed to the wireman during construction.
What columns are in this template?
Eleven columns: JB Tag, Terminal Strip, Terminal Number, Wire Number, Wire Color, Cable Number, Instrument Tag, Signal Class, From, To, Notes. Signal Class is a dropdown (AI / AO / DI / DO / N/A). Auto-filter is enabled on every column and the header row is frozen.
Can I edit the template in any spreadsheet tool?
Yes. The format is plain .xlsx and opens in Excel, Google Sheets, and LibreOffice.
Can I extend the template for a larger project?
Yes. The template ships with 48 blank rows. A typical 32-pair JB consumes ~64 terminals; the schema scales to as many JBs as the project carries. Add rows beneath the example row and the validation, filter, and column widths carry through.
How is this different from extracting straight from a P&ID?
The template is a manual starting point with the right column schema. Upload a P&ID set instead and the JB tag, instrument tag, cable number, and signal class come back populated from each loop. Terminal strip, terminal number, wire number, and wire colour are typically filled by the wiring engineer from the JB drawings rather than the P&ID.
What goes in the Wire Color column?
The IEC 60757 colour code per pair (Black / White, Black / Red, Black / Green) or the engineering standard used on the project (Blue / Brown for European hookup, polarity-coded Red / Black for North American hookup). The column accepts free text so any colour code fits.
Extract from a P&ID instead.
Upload a P&ID set instead and the JB tag, instrument tag, cable number, and signal class come back populated from each loop.