Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
IEC 62027:2011 — Preparation of Object Lists Including Parts Lists
IEC 62027:2011 establishes standardized rules for the preparation of object lists, including parts lists, bills of materials, function lists, and location lists used in electrotechnical engineering documentation. This standard is a critical component of the IEC documentation framework, ensuring that technical information about components, assemblies, and systems is presented in a consistent, unambiguous format throughout the lifecycle of an industrial installation or product.
Design Insight: IEC 62027 aligns with the reference designation system defined in IEC 81346, ensuring that object lists use a consistent structuring principle. A component identified in a schematic diagram, a 3D model, and a parts list will share the same unique reference designation, eliminating cross-document confusion in multi-discipline engineering projects.
1. Classification and Types of Object Lists
The standard defines several distinct types of object lists, each serving a specific purpose within the engineering documentation lifecycle. The choice of list type depends on whether the documentation is organized by function, location, or product structure:
| List Type | Purpose | Typical Content |
|---|---|---|
| Parts List | Detailed inventory of components in an assembly | Part numbers, quantities, descriptions, manufacturer references |
| Function List | Objects grouped by their functional role in the system | Function identifiers, reference designations, performance specs |
| Location List | Objects organized by physical installation location | Location codes, installation positions, routing data |
| Assembly List | Hierarchical breakdown of sub-assemblies and parent-child relations | Assembly levels, structural relationships, variant details |
Each list item in a parts list must contain structured column data. Class A parts lists (comprehensive) include columns for item reference (per IEC 81346), quantity, unit of measure, type identifier, textual description, characteristic properties, and cross-references to related documents. The tabular presentation shall follow the layout rules defined in IEC 61082 to ensure unambiguous interpretation by both human readers and automated data processing systems.
Important Distinction: IEC 62027 differentiates between “occurrence-oriented” lists (each individual component instance is listed separately) and “type-oriented” lists (identical components are grouped by type). Choosing the wrong orientation for the application can lead to inventory tracking errors or maintenance documentation gaps. Occurrence orientation is recommended for safety-critical installations where individual traceability is required.
2. Data Fields and Characteristic Properties
For each list item, IEC 62027 defines mandatory and optional data fields. Characteristic properties — such as rated voltage, power consumption, material, or dimensions — must be expressed using structured attribute-value pairs rather than free-form text. The standard references IEC 61360 (Component Data Dictionary / CDD) as the authoritative source for standardized property definitions and value domains.
| Column | Content | Requirement Level |
|---|---|---|
| Item Reference | Unique object identifier per IEC 81346-1 | Mandatory |
| Quantity | Number of occurrences | Mandatory |
| Unit of Measure | SI or IEC-recommended unit (pcs, m, kg, A, V, etc.) | Mandatory |
| Type Identification | Manufacturer part number, standard reference, or CDD class | Mandatory |
| Description | Free-text or structured description of the part | Mandatory |
| Characteristic Properties | Attribute-value pairs from IEC 61360 CDD | As applicable |
| Document References | Links to datasheets, drawings, specifications, certificates | As applicable |
| Weight | Mass per unit for logistics and structural loading | As applicable |
The standard strongly recommends that characteristic properties be selected from the IEC 61360 CDD dictionary, which provides globally unique property identifiers (IRDI — International Registration Data Identifier) that are machine-readable across different software platforms. This enables automated consistency checks, cost roll-ups, and material requirement planning (MRP) integration.
Design Insight: When implementing IEC 62027 in a PDM/PLM environment, create property templates per component class. For example, all electric motors share properties like rated power, nominal speed, efficiency class, and frame size; all cables share conductor cross-section, voltage rating, and flame retardance class. This pre-definition ensures data completeness and eliminates redundant data entry across projects.
3. Integration with the IEC Documentation Framework
IEC 62027 operates within a comprehensive ecosystem of documentation standards that together enable consistent technical information management across the entire lifecycle of an industrial installation:
| Standard | Role in the Framework |
|---|---|
| IEC 81346-1 / -2 | Structuring principles and reference designation system — the foundation for unique object identification across all documents |
| IEC 61082-1 | Preparation of electrotechnical documents — rules for diagrams, tables, and graphical presentations |
| IEC 61355-1 | Document classification and designation — standard document type codes used in list headers |
| IEC 61360 | Component data dictionary (CDD) — standardized property definitions with IRDI codes |
| IEC 82045-2 | Document management metadata — lifecycle and version control metadata elements |
| ISO 7200 | Title block data fields for technical product documentation |
Critical: IEC 62027 mandates revision traceability for all object lists. Every change — quantity adjustment, part substitution, specification revision — must be recorded with author identification, date, and change description. Without rigorous revision control, as-built documentation inevitably diverges from design documentation, creating serious safety risks during maintenance, retrofit, or decommissioning phases.
The standard also provides guidance on the relationship between object lists and other document types such as schematic diagrams, terminal connection diagrams, and cable schedules. A well-structured object list serves as the central index linking all technical documents that reference a given object, functioning as the information backbone of the engineering documentation set.
Frequently Asked Questions
Q: What is the practical difference between IEC 62027 and ISO 7573?
A: IEC 62027 is purpose-built for electrotechnical applications and integrates with the IEC 81346 reference designation system. ISO 7573 covers parts lists for general mechanical engineering. While both share structural similarities, IEC 62027 includes additional requirements for electrical characteristic properties, circuit identification, and alignment with IEC documentation classification codes.
Q: Can IEC 62027 lists be exchanged electronically between different engineering tools?
A: Yes. The standard supports electronic data exchange using IEC 61360 CDD-compliant XML schemas. Many commercial PDM/PLM and CAE tools (e.g., EPLAN, AutoCAD Electrical, Aveva) can import and export structured parts list data aligned with this framework, though implementation maturity varies between vendors.
Q: How does a traditional BOM differ from an IEC 62027 object list?
A: A traditional BOM is a subset of what IEC 62027 covers. While a BOM typically lists parts and quantities for manufacturing, an IEC 62027 object list can also include function-based and location-based groupings, revision history metadata, structured characteristic properties with IRDI codes, and cross-references to multiple document types — going well beyond simple identification.
