# Manual transfer switch

Canonical URL: https://eloragrid.ai/symbols/manual-transfer-switch
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: MTS
Drawing use: SLD, Schematic
Reference families: IEC, IEEE / ANSI

An operator-moved changeover switch that selects which of two sources supplies a load, with an off position between them.

## In plain English

### What does Manual transfer switch mean?

A manual transfer switch is a changeover switch operated by hand, usually with three positions: source 1, off and source 2. It is common where a portable or small standby generator connects through an inlet, and as a maintenance or bypass switch in larger systems where automatic transfer is not required.

### A simple example

The drawing is a changeover contact with a manual operator mark, often labelled I-0-II, with the two sources above and the load below. The mechanical design prevents both sources being connected at once.

### What the drawings help you do

The symbol does not tell you whether the switch can be operated on load, or whether the neutral is switched. Operating procedures, including starting the generator before moving the switch, belong in the operating instructions.

### This particular reference

An operator-moved changeover switch that selects which of two sources supplies a load, with an off position between them. A manual transfer switch relies on an operator; an automatic transfer switch senses source failure and acts on its own.

### 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.

- [Transfer switch fundamentals](https://www.cummins.com/sites/default/files/2026-04/2023-sep-transfer-switch-fundamentals.pdf)
- [Autodesk IEC-60617 preview: Operating-device and function qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-3598E18D-9F8A-48CE-83D0-4CEBA0AE869C.htm)


## What it represents

A manual transfer switch is a changeover switch operated by hand, usually with three positions: source 1, off and source 2. It is common where a portable or small standby generator connects through an inlet, and as a maintenance or bypass switch in larger systems where automatic transfer is not required.
The drawing is a changeover contact with a manual operator mark, often labelled I-0-II, with the two sources above and the load below. The mechanical design prevents both sources being connected at once.
The symbol does not tell you whether the switch can be operated on load, or whether the neutral is switched. Operating procedures, including starting the generator before moving the switch, belong in the operating instructions.

## How to read it

- The off position between sources is part of the safety function.
- Check whether the switch is rated for on-load operation.

## Information to show or reference

- State rating, poles and positions.
- Show the generator inlet or second source.
- Reference operating procedure.

## Important distinction

A manual transfer switch relies on an operator; an automatic transfer switch senses source failure and acts on its own.

## Facts

- Positions: Source 1, off, source 2
- Operation: Manual
- Typical use: Portable generator or maintenance bypass
- Preview: Independent educational illustration; consult the applicable standard and project legend for the exact graphic

## Public references

- [Transfer switch fundamentals](https://www.cummins.com/sites/default/files/2026-04/2023-sep-transfer-switch-fundamentals.pdf) — Cummins. Public transfer switch fundamentals.
- [Autodesk IEC-60617 preview: Operating-device and function qualifiers](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-3598E18D-9F8A-48CE-83D0-4CEBA0AE869C.htm) — Autodesk. Public IEC-context operating-device qualifier family for the manual operator mark.

## 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.