# Secondary-injection current input boundary

Canonical URL: https://eloragrid.ai/symbols/secondary-injection-current-input-boundary
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: SCIB
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchgear
Input: Injection current source
Output: Relay current input

Identifies where a test source applies current to the assigned measuring input circuit.

## In plain English

### What this block does

Identifies where a test source applies current to the assigned measuring input circuit.

### A simple example

In a switchgear relay panel, test links can separate a protective relay from the trip coils while maintaining the specified current-transformer secondary arrangement. For this reference, the drawing identifies “Injection current source” at the input and “Relay current input” at the output. The live CT connection needs a separate defined arrangement.

### What the drawings help you do

Start at the named input: Injection current source. Identify its source device or document and the state represented on the drawing. Follow the named output: Relay current input. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Injection current source
- Output: Relay current input
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Injection current source → SCIB → Relay current input
A reading guide. The entry's original illustration and input/output facts describe this application.

- [Masterclad medium-voltage switchgear: circuit-breaker section interlocks](https://productinfo.se.com/masterclad_mv_switchgear_ib/6055-30-masterclad-15kv-mv-switchgear-ib/English/6055-30%20Masterclad%20MV%20Switchgear%20Indoor%20%28bookmap%29_DD00646805.xml/%24/Section6-CircuitBreakerSectionInter-58DD6EC7)


## What it represents

Identifies where a test source applies current to the assigned measuring input circuit. A test interface separates measurement, command and indication paths so their behavior can be checked in the documented test configuration. The test boundary must show which real equipment outputs remain enabled.
In a switchgear relay panel, test links can separate a protective relay from the trip coils while maintaining the specified current-transformer secondary arrangement. For this reference, the drawing identifies “Injection current source” at the input and “Relay current input” at the output. The live CT connection needs a separate defined arrangement.
Trace the source and destination on each side of the test boundary. Use the selected test-device instructions for actual operations and never infer a safe current-transformer switching sequence from an educational diagram. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation.

## How to read it

- Start at the named input: Injection current source. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Relay current input. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- The live CT connection needs a separate defined arrangement.
- Trace the source and destination on each side of the test boundary. Use the selected test-device instructions for actual operations and never infer a safe current-transformer switching sequence from an educational diagram.

## Information to show or reference

- Label the source and connection reference for injection current source.
- Identify the destination and defined state of relay current input.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: The live CT connection needs a separate defined arrangement.

## Important distinction

The live CT connection needs a separate defined arrangement. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram.

## Facts

- Representation: Functional block
- Installation focus: Switchgear
- Input / boundary: Injection current source
- Output / connection: Relay current input
- Lookup label: SCIB is a library lookup label, not a standard device designation.

## Public references

- [Masterclad medium-voltage switchgear: circuit-breaker section interlocks](https://productinfo.se.com/masterclad_mv_switchgear_ib/6055-30-masterclad-15kv-mv-switchgear-ib/English/6055-30%20Masterclad%20MV%20Switchgear%20Indoor%20%28bookmap%29_DD00646805.xml/%24/Section6-CircuitBreakerSectionInter-58DD6EC7) — Schneider Electric. Public technical context for switchgear test and commissioning interfaces. Breaker control, mechanism, position contacts, racking interlocks and test interfaces. The application text and educational graphic are independently authored; the publisher does not certify this representation.

## 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.