# Trip-circuit supervision relay

Canonical URL: https://eloragrid.ai/symbols/trip-circuit-supervision-relay
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: TCS
Drawing use: Schematic
Reference families: IEC, Manufacturer

Relay that passes a small current through the trip circuit to check continuity and alarms if the circuit is broken.

## In plain English

### What does Trip-circuit supervision relay mean?

A trip-circuit supervision relay monitors the wiring, auxiliary contacts and trip coil of a circuit breaker by passing a current too small to trip it. If the trip circuit is broken or its supply fails, the relay drops out and raises an alarm, so a failed trip path is found before a fault needs it.

### A simple example

Schemes differ in whether they supervise the circuit with the breaker open and closed, which needs resistors or connections across the breaker auxiliary contacts. The symbol shows the relay but the reader must check which states are actually covered.

### What the drawings help you do

Check supervision covers both breaker positions. Verify the supervision current cannot operate the trip coil. Trip-circuit supervision monitors trip path continuity; a lockout relay latches after a trip.

### This particular reference

Relay that passes a small current through the trip circuit to check continuity and alarms if the circuit is broken. Trip-circuit supervision monitors trip path continuity; a lockout relay latches after a trip.

### Terms

- Normally open / normally closed: The contact state in the normal condition defined for the drawing.
- Coil: A wound conductor that can produce a magnetic field when energised.
- Terminal: An identified point where a conductor connects.

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.

- [Relion 620: functions, codes and symbols](https://techdoc.relays.protection-control.abb/r/620-series-IEC-60870-5-103-Point-List-Manual/2.0-FP1-IEC/en-US/Functions-codes-and-symbols)
- [IEC graphical symbols for diagrams](https://tc3.iec.ch/tc-activity/graphical-symbols-for-diagrams/)


## What it represents

A trip-circuit supervision relay monitors the wiring, auxiliary contacts and trip coil of a circuit breaker by passing a current too small to trip it. If the trip circuit is broken or its supply fails, the relay drops out and raises an alarm, so a failed trip path is found before a fault needs it.
Schemes differ in whether they supervise the circuit with the breaker open and closed, which needs resistors or connections across the breaker auxiliary contacts. The symbol shows the relay but the reader must check which states are actually covered.

## How to read it

- Check supervision covers both breaker positions.
- Verify the supervision current cannot operate the trip coil.

## Information to show or reference

- Show connections across trip contacts
- State supervised breaker states
- Reference alarm output

## Important distinction

Trip-circuit supervision monitors trip path continuity; a lockout relay latches after a trip.

## Facts

- Monitored items: Trip coil, wiring and supply
- Output: Alarm on loss of continuity
- Preview: Independent educational concept; consult the applicable standard and project legend for the exact graphic

## Public references

- [Relion 620: functions, codes and symbols](https://techdoc.relays.protection-control.abb/r/620-series-IEC-60870-5-103-Point-List-Manual/2.0-FP1-IEC/en-US/Functions-codes-and-symbols) — ABB. Public relay function list including trip-circuit supervision.
- [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.