# Maximum-demand indicator

Canonical URL: https://eloragrid.ai/symbols/maximum-demand-indicator
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: MD
Drawing use: SLD, Schematic
Reference families: IEC, Manufacturer

Indicating instrument with a resettable pointer or register showing the highest averaged current or power reached.

## In plain English

### What does Maximum-demand indicator mean?

A maximum-demand indicator shows the highest averaged load reached since it was last reset. Thermal demand ammeters with a drag pointer were common on switchboard feeders and transformer secondaries, and they help assess loading without a full recording instrument.

### A simple example

Thermal types respond with a time constant rather than a fixed interval, so their readings are not directly comparable with tariff demand meters. The symbol does not show the response time or reset method, both of which affect how the reading is used.

### What the drawings help you do

Check the response time or demand interval. Note when the indicator was last reset. A maximum-demand indicator shows only the peak averaged value; a maximum-demand meter also totalises energy.

### This particular reference

Indicating instrument with a resettable pointer or register showing the highest averaged current or power reached. A maximum-demand indicator shows only the peak averaged value; a maximum-demand meter also totalises energy.

### Terms

- Winding: A coil of conductor inside an electrical machine or transformer.
- 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/)


## What it represents

A maximum-demand indicator shows the highest averaged load reached since it was last reset. Thermal demand ammeters with a drag pointer were common on switchboard feeders and transformer secondaries, and they help assess loading without a full recording instrument.
Thermal types respond with a time constant rather than a fixed interval, so their readings are not directly comparable with tariff demand meters. The symbol does not show the response time or reset method, both of which affect how the reading is used.

## How to read it

- Check the response time or demand interval.
- Note when the indicator was last reset.

## Information to show or reference

- State quantity and interval
- Show CT input
- Describe reset method

## Important distinction

A maximum-demand indicator shows only the peak averaged value; a maximum-demand meter also totalises energy.

## Facts

- Displayed quantity: Highest averaged current or power
- Reset: Manual or periodic
- Preview: Independent educational concept; consult the applicable standard and project legend for the exact graphic

## Public references

- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/) — IEC. IEC context for graphical symbols used in diagrams; no IEC graphic is reproduced.

## 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.