# Ring main unit

Canonical URL: https://eloragrid.ai/objects/ring-main-unit
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: RMU
Drawing use: GA
Reference families: Manufacturer

A secondary-distribution switchgear assembly with a selected combination of switching functions.

## What it represents

A ring main unit is a compact secondary-distribution switchgear assembly with a manufacturer-defined combination of switching functions. Its electrical configuration and physical envelope depend on the chosen product, rather than on the abbreviation RMU alone.
The original envelope illustration is unscaled and has no manufacturer dimensions. Follow the cited public resources to the exact product, then use its current drawing and installation information for engineering work.

## How to read it

- Identify the number and function of the selected ways.
- Keep the electrical configuration linked to the manufacturer GA.

## Information to show or reference

- Reference the exact unit configuration.
- Check cable interfaces and installation information.
- Match the SLD ways to physical sections.

## Important distinction

RMU does not specify one universal technology, dimension or combination of breaker, switch and fused ways.

## Facts

- Object type: Generic equipment reference
- Dimensions: Use the exact manufacturer/model drawing
- Illustration scale: Not to scale
- Download scope: Original concept envelope only

## Public references

- [Secondary-distribution switchgear and ring main units](https://new.abb.com/medium-voltage/switchgear/secondary-distribution) — ABB. Public ring-main-unit and secondary-distribution equipment 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.