# Fault passage indicator

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

Device on an MV cable or overhead feeder that shows whether fault current has passed its location, to speed fault finding.

## In plain English

### What does Fault passage indicator mean?

A fault passage indicator senses current at a point on a medium-voltage feeder and shows, with a flag or LED, when fault current has passed. Operators follow the indicators along a feeder to find the faulted section between the last operated indicator and the first unoperated one.

### A simple example

Indicators may sense phase faults, earth faults or both, and many can signal remotely to SCADA. The symbol does not show the sensing method, reset method or thresholds, which must suit the network earthing and feeder load to avoid false or missed indications.

### What the drawings help you do

Check whether the indicator covers phase faults, earth faults or both. Note any remote signalling output. A fault passage indicator only signals; a protection relay trips a breaker.

### This particular reference

Device on an MV cable or overhead feeder that shows whether fault current has passed its location, to speed fault finding. A fault passage indicator only signals; a protection relay trips a breaker.

### Terms

- Phase: One of the related AC waveforms in a power system.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.
- Rating: A value stating the conditions for which equipment is specified.

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.

- [Secondary-distribution switchgear and ring main units](https://new.abb.com/medium-voltage/switchgear/secondary-distribution)


## What it represents

A fault passage indicator senses current at a point on a medium-voltage feeder and shows, with a flag or LED, when fault current has passed. Operators follow the indicators along a feeder to find the faulted section between the last operated indicator and the first unoperated one.
Indicators may sense phase faults, earth faults or both, and many can signal remotely to SCADA. The symbol does not show the sensing method, reset method or thresholds, which must suit the network earthing and feeder load to avoid false or missed indications.

## How to read it

- Check whether the indicator covers phase faults, earth faults or both.
- Note any remote signalling output.

## Information to show or reference

- State fault types detected
- State reset method
- Reference SCADA signal

## Important distinction

A fault passage indicator only signals; a protection relay trips a breaker.

## Facts

- Location: MV cable or overhead feeder
- Output: Local flag or LED and optional remote signal
- Preview: Functional illustration of the device role; not a product footprint or certified standard graphic

## Public references

- [Secondary-distribution switchgear and ring main units](https://new.abb.com/medium-voltage/switchgear/secondary-distribution) — ABB. Public secondary-distribution switchgear and ring main unit context where fault indicators are fitted.

## 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.