Protection functions · 59A

Auxiliary-input overvoltage

Supervises high voltage on the auxiliary measurement input in the cited Eaton family.

SLD / Schematic · 59AAuxiliary-input overvoltage: original educational illustration
Original educational illustrationNot to scale · See source and graphic notes

What it represents

Supervises high voltage on the auxiliary measurement input in the cited Eaton family.

The drafting record should connect this function to the auxiliary voltage input and the electrical node it measures, then trace the auxiliary overvoltage trip or control output. 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 auxiliary voltage input and the electrical node it measures.
  • Trace the auxiliary overvoltage trip or control output.

Information to show or reference

  • Label the auxiliary voltage input and the electrical node it measures.
  • Cross-reference the auxiliary overvoltage trip or control output.
  • Retain the complete suffix, selected device tag and manufacturer manual revision.

A distinction that matters

Auxiliary-input A distinguishes the input circuit here; it does not universally indicate an alarm-only function.

Sources you can follow

These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.

ETR-4000 and ETR-5000 transformer protection function tables

Public primary-source function or application mapping used to identify this designation; wording and drafting notes are original.

Eaton · Public reference checked 13 October 2026 · Link only

IEEE C37.2-2022: power-system device function numbers

Device-number and suffix convention. This page is not a reproduction of the full licensed standard.

IEEE · Public reference checked 13 October 2026 · Link only

About this graphic

This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.

SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.

Entry JSON · Entry Markdown · Last editorial update: 13 October 2026

Put the reference into a drawing workflow.

Elora Grid helps electrical teams work with drawings, specifications and equipment information. Explore the drafting workflow or join the early-access waitlist.

Explore drafting