# Main-input overvoltage

Canonical URL: https://eloragrid.ai/protection-functions/59m-main-input-overvoltage
Publisher: Elora Grid
Updated: 2026-10-13
Lookup label: 59M
Drawing use: SLD, Schematic
Reference families: IEEE / ANSI, Manufacturer

Supervises high voltage using the main three-phase inputs in the cited Eaton family.

## What it represents

Supervises high voltage using the main three-phase inputs in the cited Eaton family.
The drafting record should connect this function to the main VT circuit and phase input assignments, then trace the main overvoltage operating outputs. Keep the complete designation and equipment tag together so that the SLD, relay logic and terminal schedule describe the same implementation.
The cited mapping is a public manufacturer example (Eaton ETR family). Suffixes are not universal equivalences across products, and this reference supplies neither a protection setting nor certification of the selected scheme.

## How to read it

- Identify the main VT circuit and phase input assignments.
- Trace the main overvoltage operating outputs.

## Information to show or reference

- Label the main VT circuit and phase input assignments.
- Cross-reference the main overvoltage operating outputs.
- Retain the complete suffix, selected device tag and manufacturer manual revision.

## Important distinction

59M and 59A can supervise different voltage sources; their labels should match the VT circuits shown.

## Facts

- Function designation: 59M
- Base function: 59 — Overvoltage
- Published mapping: Eaton ETR family
- Suffix scope: Application or manufacturer specific; check the complete drawing legend and selected device manual.

## Public references

- [ETR-4000 and ETR-5000 transformer protection function tables](https://www.eaton.com/us/en-us/catalog/electrical-circuit-protection/transformer-relays.html) — Eaton. Public primary-source function or application mapping used to identify this designation; wording and drafting notes are original.
- [IEEE C37.2-2022: power-system device function numbers](https://ieeexplore.ieee.org/document/9984140) — IEEE. Device-number and suffix convention. This page is not a reproduction of the full licensed standard.

## 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.