Room alarm common-contact output

What it represents

Provides the documented common contact representing the selected group of room alarms. A room DC interface connects station battery distribution, alarm contacts and operating circuits. DC supplies may remain energized when the room's normal AC supply is unavailable, so their source and distribution boundaries must be shown separately.

In a switchroom, the station battery can continue supplying protection and breaker controls during an AC supply interruption. The alarm system should distinguish charger loss from a low battery condition. For this reference, the drawing identifies “Assigned alarm group” at the input and “Common station alarm contact” at the output. The common contact does not replace detailed alarm records.

Identify the DC source, returns and monitored branches. Do not infer battery autonomy, conductor polarity, isolation or earthing arrangements from a generic power block. 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: Assigned alarm group. Identify its source device or document and the state represented on the drawing.
• Follow the named output: Common station alarm contact. Cross-reference its destination and separate the command from confirmation that the equipment responded.
• The common contact does not replace detailed alarm records.
• Identify the DC source, returns and monitored branches. Do not infer battery autonomy, conductor polarity, isolation or earthing arrangements from a generic power block.

Information to show or reference

• Label the source and connection reference for assigned alarm group.
• Identify the destination and defined state of common station alarm contact.
• Record the equipment or control-document revision supporting this functional block.
• Check this application limit in the project design: The common contact does not replace detailed alarm records.

Sources you can follow

These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.

About this graphic

This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.

SVG and DXF downloads contain this original artwork. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.