# Cable branch joint

Canonical URL: https://eloragrid.ai/symbols/iec-cable-branch-joint
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: J
Drawing use: SLD, GA
Reference families: IEC

## Symbol convention

Convention: IEC
Form: Branch cable joint
Independent IEC-context illustration; not certified IEC geometry.

A cable joint where a branch cable is taken off a main cable, drawn as a joint with a third cable leaving it.

## In plain English

### What does Cable branch joint mean?

A branch or tee joint connects a branch cable to a main cable without terminating the main cable at a switchboard. It is common on low voltage street mains and some legacy medium voltage networks, where services or spur cables are taken from the main along its route.

### A simple example

The symbol shows the circuit arrangement but not the protection of the branch. A branch made by a joint generally has no switching or fault isolation at the tee, so faults on the branch affect the main circuit's protection. Readers should check protection grading and fault level at the branch cable.

### What the drawings help you do

Check how the branch is protected, since there may be no device at the joint. Record joint location for fault finding. A branch joint connects a third cable mid-route; a one-line bus tap is a connection to a busbar, not a cable.

### This particular reference

A cable joint where a branch cable is taken off a main cable, drawn as a joint with a third cable leaving it. A branch joint connects a third cable mid-route; a one-line bus tap is a connection to a busbar, not a cable.

### Terms

- Normally open / normally closed: The contact state in the normal condition defined for the drawing.
- Rating: A value stating the conditions for which equipment is specified.
- Schematic: A drawing showing function and connections rather than physical appearance.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [Elastimold underground cable accessories](https://www.abb.com/global/en/areas/electrification/medium-voltage/cable-accessories-connectors/underground/elastimold/underground)
- [IEC-60617 symbol preview directory](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-7871E6EF-24D5-467E-9B74-321FEDC9DFDA.htm)


## What it represents

A branch or tee joint connects a branch cable to a main cable without terminating the main cable at a switchboard. It is common on low voltage street mains and some legacy medium voltage networks, where services or spur cables are taken from the main along its route.
The symbol shows the topology but not the protection of the branch. A branch made by a joint generally has no switching or fault isolation at the tee, so faults on the branch affect the main circuit's protection. Readers should check protection grading and fault level at the branch cable.

## How to read it

- Check how the branch is protected, since there may be no device at the joint.
- Record joint location for fault finding.

## Information to show or reference

- Show the branch cable size and type.
- Confirm protection covers the branch.
- Locate the joint on the route drawing.

## Important distinction

A branch joint connects a third cable mid-route; a one-line bus tap is a connection to a busbar, not a cable.

## Facts

- Graphic cue: Joint mark with a third cable leaving at an angle
- Typical use: LV mains with service branches
- Preview: Original educational illustration; consult the publisher and applicable standard for the exact graphic

## Public references

- [Elastimold underground cable accessories](https://www.abb.com/global/en/areas/electrification/medium-voltage/cable-accessories-connectors/underground/elastimold/underground) — ABB. Manufacturer context for underground cable joints.
- [IEC-60617 symbol preview directory](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-7871E6EF-24D5-467E-9B74-321FEDC9DFDA.htm) — Autodesk. Public directory of IEC-oriented symbol families.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.