# Truck-position racking interlock

Canonical URL: https://eloragrid.ai/symbols/truck-position-racking-interlock
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: TRI
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchgear
Input: Breaker and truck states
Output: Racking permission

Restricts breaker racking according to its documented operating and truck-position conditions.

## In plain English

### What this block does

Restricts breaker racking according to its documented operating and truck-position conditions.

### A simple example

In a switchgear feeder panel, a control diagram can prevent an incompatible combination of breaker, disconnector and earthing-switch positions. The physical equipment documents determine which restrictions are mechanically enforced. For this reference, the drawing identifies “Breaker and truck states” at the input and “Racking permission” at the output. Mechanical restrictions remain equipment-specific.

### What the drawings help you do

Start at the named input: Breaker and truck states. Identify its source device or document and the state represented on the drawing. Follow the named output: Racking permission. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Breaker and truck states
- Output: Racking permission
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Breaker and truck states → TRI → Racking permission
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

Restricts breaker racking according to its documented operating and truck-position conditions. An interlocking function permits or blocks an operation according to the positions and conditions of related equipment. Electrical, mechanical and trapped-key interlocks implement different parts of a coordinated operating philosophy.
In a switchgear feeder panel, a control diagram can prevent an incompatible combination of breaker, disconnector and earthing-switch positions. The physical equipment documents determine which restrictions are mechanically enforced. For this reference, the drawing identifies “Breaker and truck states” at the input and “Racking permission” at the output. Mechanical restrictions remain equipment-specific.
Identify each initiating position, the action being blocked and the consequence of missing feedback. An illustrative logic diagram must not be treated as an operating procedure or proof of a complete safety system. 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: Breaker and truck states. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Racking permission. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Mechanical restrictions remain equipment-specific.
- Identify each initiating position, the action being blocked and the consequence of missing feedback. An illustrative logic diagram must not be treated as an operating procedure or proof of a complete safety system.

## Information to show or reference

- Label the source and connection reference for breaker and truck states.
- Identify the destination and defined state of racking permission.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Mechanical restrictions remain equipment-specific.

## Important distinction

Mechanical restrictions remain equipment-specific. 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: Breaker and truck states
- Output / connection: Racking permission
- Lookup label: TRI 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 interlocking functions. 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.