BS EN IEC 81346-2:2019 Industrial systems, installations and equipment and industrial products. Structuring principles and reference designations Classification of objects and codes for classes

Electronic equipment and components
Diagrams
Electrical equipment
Electric power systems
Production equipment
Engineering drawings
Identification methods
Letters (symbols)
Water transport engineering
Construction
Industrial
Circuit diagrams
Codes
Technical documents
Electrical components
Designations
Classification systems

Link: BS EN IEC 81346-2:2019 Industrial systems, installations and equipment and industrial products. Structuring principles and reference designations Classification of objects and codes for classes
Source: BSI Standards