OpenCDD · IEC Common Data Dictionary
Common ground. Preserved differences.
An open, modern browser for the IEC Common Data Dictionary —24,856 entities across 7 published dictionaries, every class and property bound to one globally unique IRDI. Many domains, many languages, one shared vocabulary.
What is the IEC Common Data Dictionary?
A structured catalogue of product characteristics, maintained by IEC TC 3 — and a four-layer model with native power-type semantics.
The dictionary captures product concepts as entities called classes and their characteristics as entities called properties. Every entity — every class, property, value list, value term, unit, and relation — is bound to a globally unique IRDI, versioned, and translated.
CDD is distinctive because instances can themselves act as classes elsewhere in the dictionary. This is the structural foundation for interoperability: each domain preserves its own terminology while sharing the same identifiers.
Dictionaries
Six published IEC dictionaries
Click any dictionary to browse its classes, properties, value lists, and relations.
IEC CDD reference dictionary
iec61360IEC 61360 (series) · 2017 · IEC TC 3
IEC 61360-1:2017 "specifies principles for the definition of the properties and associated attributes and explains the methods for representing verbally defined concepts in a computer-sensible form that is independent of natural language." The browser hosts the IEC 61360-4 reference dictionary itself — the canonical catalogue of classes, properties, value lists, units, and relations for electrotechnical components — together with content drawn from across the IEC 61360 series.
- Classes 574
- Properties 2018
- Value lists 318
- Value terms 1866
4,776 entitiesBrowse →Cross-domain general items
iec61360-7IEC 61360-7:2024 · 2024 · IEC TC 3
IEC 61360-7:2024 "specifies the IEC CDD 'General items' data dictionary of cross-domain concepts, classes, properties and qualifiers for use in electrotechnology and related areas." The data dictionary provides concepts (dictionary elements such as classes and properties) intended for cross-domain use across all dictionaries in the IEC 61360 framework, rather than within a single product domain.
- Classes 57
- Properties 215
- Value lists 49
- Value terms 1997
2,318 entitiesBrowse →Industrial measurement and control
iec61987IEC 61987 (series) · IEC TC 65
IEC 61987-1:2024 "defines a generic structure in which product features of industrial process measurement devices shall be arranged, in order to facilitate the categorization of those product features, their representation by defined properties, and their exchange by properties." The series includes generic structures (Part 1), Lists of Properties for operating and device parameters (OLOP/DLOP, Parts 13–15), and domain-specific type blocks for valves, positioners, actuators, and analysers (Parts 20+).
- Classes 2704
- Properties 6471
- Value lists 669
- Value terms 3496
13,340 entitiesBrowse →Low-voltage switchgear
iec62683IEC 62683-1:2026 · 2026 · IEC SC 121A
IEC 62683-1:2026 "establishes the reference dictionary of the general description of classes of low-voltage switchgear and controlgear and their assemblies based on defined properties." It provides standardised data structures for catalogue data, enabling consistent information exchange across engineering tools, e-commerce platforms, and asset-management systems.
- Classes 375
- Properties 765
- Value lists 139
- Value terms 582
- Relations 10
1,871 entitiesBrowse →Quantities & Units (IEC 62720)
iec62720IEC 62720:2023 · 2023 · IEC TC 1
IEC 62720 provides an unambiguous set of identifiers for quantities and units used in electrotechnology. Each quantity and unit receives a globally unique code within the IEC CDD framework, ensuring consistent terminology across all IEC product standards.
- Classes 1
- Units 2165
- Relations 6
2,172 entitiesBrowse →Power measurement applications
iec63213IEC TR 63213:2019 · 2019 · IEC TC 85
IEC TR 63213:2019 "intends to provide state-of-the-art information on the various electricity measurement applications made in the grid (supply side) or in electrical installations (demand side)." The Technical Report surveys the relevant international standards associated with each application and the contractual mechanisms for verifying the quality of delivered energy.
- Classes 26
- Properties 67
- Value lists 10
- Value terms 114
- Relations 7
224 entitiesBrowse →Miniature circuit-breakers (MCBs)
iec63508IEC 63508:2026 · 2026 · IEC SC 23E
IEC 63508:2026 "describes product classes and properties, representing the miniature circuit-breaker (MCB), to become a part of the IEC 61360-4: IEC CDD." It covers the data required for product selection as well as the data required for engineering, streamlining selection, engineering, and database integration.
- Classes 23
- Properties 33
- Value lists 9
- Value terms 86
- Relations 4
155 entitiesBrowse →OceanRunner (demonstration)
oceanrunnerDemonstrationA synthetic CDD dictionary used to exercise the browser end-to-end and to illustrate power-type modelling in the docs. Not a published IEC standard. Models a fictional 'OceanRunner' transmedium vehicle manufacturer (boat / car / submarine product lines) with categorical classes, conditional properties, CLASS_REFERENCE data types, and configured-product subclasses. All entities share the IRDI scheme 0112/2///OCEANRUNNER#.
- Classes 20
- Properties 19
- Value lists 1
40 entitiesExplore the demo →
From the blog
Updates, deep dives, notes.
July 22, 2026
OpenCDD July 2026: full interoperability with CDD data
Seven IEC dictionaries, 23,000+ entities, interactive relationship graphs, version history with real diffs, cross-dictionary concept matching, and three open-source tools that round-trip CDD data end to end.
July 12, 2026
Introducing OpenCDD
A modern, open-source browser and tooling ecosystem for the IEC Common Data Dictionary. Why we built it, where it is today, and where it is going.