IEC GUIDE 103:1980 pdf download,Guide on dimensional co-ordination.
IEC Guide 103:1980 “Guide on dimensional co-ordination” provides recommended dimensional-size systems used in the electrotechnical field to make interfaces between components, devices, and equipment compatible. Its central idea is to achieve dimensional coordination while also controlling the number (“varieties”) of possible size options, so products remain interoperable and manufacturers can design to consistent interfaces.
The guide defines two main recommended approaches to dimensional coordination. One approach is based on common electrotechnical grid pitches used for reference grids—such as 0.5 mm, 1 mm, 5 mm, 12.5 mm, 25 mm, 50 mm, 100 mm, and 200 mm—so that standardized sizes align with frequently used spacing conventions. The second approach prioritizes interface aspects, including additivity (how dimensions combine predictably), the use of reference grids, and relationships between “containers” and “contained” parts (outer frameworks and inner elements). It uses a binary-based series of sizes adapted to normal electrotechnical practice, aiming to preserve interface properties while offering structured size progression.
Overall, IEC Guide 103 serves as a coordinating framework to reduce dimensional incompatibility, simplify design and manufacturing, and support consistent mechanical/electromechanical integration across electrotechnical products