# Local isolator plan mark

Canonical URL: https://eloragrid.ai/symbols/iec-local-isolator-plan-mark
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: ISO
Drawing use: GA
Reference families: IEC

## Symbol convention

Convention: IEC
Form: Isolating switch, installation plan
IEC 60617 installation-plan style (architectural and topographical installation symbols); independently drawn, not certified IEC geometry or a database identifier.

Plan mark for a local isolating switch placed beside fixed equipment for safe maintenance.

## In plain English

### What does Local isolator plan mark mean?

Local isolators are placed within sight of motors, air-conditioning units, pumps and fans so maintenance staff can isolate and lock the supply. Plans draw a small switch box with an isolation mark or the letters ISO beside the equipment it serves, sometimes with a lock indication.

### A simple example

The mark tells the installer to provide a device rated for isolation and, where required, lockable in the off position. Pole count follows the supply: three-pole or four-pole for three-phase plant. It does not specify utilisation category or whether the device can switch motor load. Those are in the schedule.

### What the drawings help you do

Check it is within sight of the equipment. Confirm pole count and locking provision. A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.

### This particular reference

Plan mark for a local isolating switch placed beside fixed equipment for safe maintenance. A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.

### Terms

- Phase: One of the related AC waveforms in a power system.
- 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.

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/)
- [Elementary switching devices](https://www.electrical-installation.org/enwiki/Elementary_switching_devices)


## What it represents

Local isolators are placed within sight of motors, air-conditioning units, pumps and fans so maintenance staff can isolate and lock the supply. Plans draw a small switch box with an isolation mark or the letters ISO beside the equipment it serves, sometimes with a lock indication.
The mark tells the installer to provide a device rated for isolation and, where required, lockable in the off position. Pole count follows the supply: three-pole or four-pole for three-phase plant. It does not specify utilisation category or whether the device can switch motor load. Those are in the schedule.

## How to read it

- Check it is within sight of the equipment.
- Confirm pole count and locking provision.

## Information to show or reference

- State poles and rating.
- State lockability.
- Tag the equipment served.

## Important distinction

A switched socket outlet is not an isolator; this plan mark designates an isolation-rated device.

## Facts

- Purpose: Isolation for maintenance
- Typical equipment: Fans, pumps, condensers, motors
- Exact standard graphic: Not reproduced here; confirm the form against IEC 60617 and the project legend

## Public references

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) — IEC. IEC graphical symbol context; independently drawn here.
- [Elementary switching devices](https://www.electrical-installation.org/enwiki/Elementary_switching_devices) — Schneider Electric — Electrical Installation Guide. Explains the isolation function and its requirements.

## 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.