# Station-service transformer incoming branch

Canonical URL: https://eloragrid.ai/symbols/station-service-transformer-incoming-branch
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: STIB
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: switchrooms
Input: Station-service transformer
Output: Auxiliary board incoming circuit

Shows the auxiliary board connection supplied by the station-service transformer.

## In plain English

### What this block does

Shows the auxiliary board connection supplied by the station-service transformer.

### A simple example

In a switchroom, the lighting, service sockets, charger input and room cooling may be fed from different auxiliary branches. A source change must preserve the identities of loads that require continuity. For this reference, the drawing identifies “Station-service transformer” at the input and “Auxiliary board incoming circuit” at the output. Primary and secondary protection are separately designed.

### What the drawings help you do

Start at the named input: Station-service transformer. Identify its source device or document and the state represented on the drawing. Follow the named output: Auxiliary board incoming circuit. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Station-service transformer
- Output: Auxiliary board incoming circuit
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Station-service transformer → STIB → Auxiliary board incoming circuit
A reading guide. The entry's original illustration and input/output facts describe this application.

- [SEL-RPM redundant power module](https://selinc.com/products/RPM/)


## What it represents

Shows the auxiliary board connection supplied by the station-service transformer. An auxiliary AC distribution diagram identifies the supplies serving room services and control-support equipment. Essential, backed-up and ordinary circuits can have different source paths and operating priorities.
In a switchroom, the lighting, service sockets, charger input and room cooling may be fed from different auxiliary branches. A source change must preserve the identities of loads that require continuity. For this reference, the drawing identifies “Station-service transformer” at the input and “Auxiliary board incoming circuit” at the output. Primary and secondary protection are separately designed.
Label source, branch protection and load purpose. The arrangement does not establish conductor sizes, protection settings or installation compliance; it links the operating role to the selected equipment schedule. 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: Station-service transformer. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Auxiliary board incoming circuit. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Primary and secondary protection are separately designed.
- Label source, branch protection and load purpose. The arrangement does not establish conductor sizes, protection settings or installation compliance; it links the operating role to the selected equipment schedule.

## Information to show or reference

- Label the source and connection reference for station-service transformer.
- Identify the destination and defined state of auxiliary board incoming circuit.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Primary and secondary protection are separately designed.

## Important distinction

Primary and secondary protection are separately designed. 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: Switchrooms
- Input / boundary: Station-service transformer
- Output / connection: Auxiliary board incoming circuit
- Lookup label: STIB is a library lookup label, not a standard device designation.

## Public references

- [SEL-RPM redundant power module](https://selinc.com/products/RPM/) — SEL. Public technical context for switchroom auxiliary ac distribution. Independent AC and DC sources for station auxiliary power. 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.