Glossary · Engineering, integration and validation
Electrical schematic
Also known as: Circuit diagram, Schematic diagram
German: Stromlaufplan
In electrical engineering, an electrical schematic (circuit diagram) shows the circuits of an electrical installation or machine with graphical symbols, arranged by function rather than physical location, so that its operation can be understood. Devices are identified by reference designations.
- Validation
- Technical documentation
- Standards
In one sentence
An electrical schematic shows circuits with standard symbols arranged by function, so the operation of an installation or machine can be understood.
Example
The electrical schematic of the press shows the emergency stop circuit on sheet 12, with the safety relay -K10 and the contactors -Q1 and -Q2.
How it applies
- Engineering: Electrical designers create schematics in an electrical CAD tool, using graphical symbols from IEC 60617 and reference designations according to IEC 81346. Document preparation rules are given in IEC 61082-1.
- Commissioning and maintenance: Electricians use the schematic to trace signals, check interlocks and find faults; it must match the installed state.
- Compliance: IEC 60204-1 requires documentation of the electrical equipment of machines, typically including circuit diagrams.
- Documentation: The documentation team references schematic sheets and device designations in troubleshooting and maintenance instructions, and makes sure revisions of manuals and schematics are released together.
Electrical schematic vs. wiring diagram
A schematic shows how circuits work, arranged by function. A Wiring diagram shows the physical connections between terminals, devices and cables for installation. Both are needed; they describe the same equipment from different views.