Overview
ISO 9247:1990 - "Earth‑moving machinery - Electrical wires and cables - Principles of identification and marking" sets out fundamental principles for identifying and marking wires and cables used in earth‑moving machinery. The standard defines an identification/coding system to simplify assembly, maintenance, fault finding and repair of electrical circuits in machines defined by ISO 6165. It does not cover internal wiring inside electrical components (e.g., alternators, relays).
Key topics and requirements
- Identification methods: Wires and cables may be identified by numbers, colors, literal symbols, or combinations of these elements. Uppercase letters may be combined with digits for additional identification.
- Character selection: Avoid characters that can be confused with digits - the document explicitly cites examples (B, D, 1, 0, Q) as potentially ambiguous.
- Uniqueness and consistency:
- Identification must be identical at both ends of a wire/cable.
- Each identification code must be unique per machine and changed when a wire/cable crosses an electrical component.
- Color coding rules:
- Identification by insulation color along the full length or by a color band at each end is permitted.
- Red is specified for wires/cables that are constantly live (under tension), e.g., main positive battery connections, alternator outputs, starter motor feed.
- The negative (battery negative/earth) conductor is identified by the digit "0", a negative sign, or black color.
- Use contrasting tracer bands, strips or non‑conductive labels when additional differentiation is required.
- Placement and durability:
- Markings (bands, labels, colors) should be visible and placed within 150 mm of each end of the wire/cable; additional markings along the length are allowed if needed.
- Coding should be integral to the insulation or firmly attached and protected during painting, maintenance or servicing to preserve legibility.
- Documentation alignment: Marking and coding must be harmonized with the wiring diagrams supplied with each machine.
Applications and users
ISO 9247 is practical for:
- OEM designers and manufacturers of earth‑moving machinery
- Electrical engineers producing wiring diagrams and harness layouts
- Maintenance technicians and service teams for fault diagnosis and repairs
- Fleet managers and safety inspectors who require consistent wire/cable identification for safe maintenance
Keywords: ISO 9247, earth‑moving machinery, electrical wires and cables, wire identification, cable marking, color coding, wiring diagrams, maintenance.
Related standards
- ISO 6165 (earth‑moving machinery - main types - vocabulary)
- ISO 6749 (equipment conservation and storage)
- IEC/CEI 617 (graphical symbols for diagrams)
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