SIST EN 3745-203:2008

Overview

EN 3745-203:2008 is a CEN European Standard in the Aerospace series that specifies a test method for measuring fibre optic cable dimensions intended for aircraft use. It is a part-specific method (Part 203: Cable dimensions) and is intended to be used together with EN 3745-100 (General test methods). The standard defines specimen preparation, required apparatus, measurement procedures and how to report final dimensional and mass results for optical cables in aerospace applications.

Key Topics

• Scope and linkage: Applies to measurement of cable outer diameter, buffer/tube and jacket thickness, concentricity and cable mass; used in conjunction with EN 3745-100.
• Specimen preparation:
  • Cross-sectional slice of insulation for tube and jacket measurements.
  • Tight buffer samples: minimum 3 m length.
  • Mass samples: minimum 1 m length.
• Apparatus:
  • Profile projector, measuring microscope or equivalent with at least 10× magnification.
  • Readings: typically to 2 decimal places; estimate a 3rd decimal when thickness < 0.5 mm.
  • Mass and length measurement equipment with accuracy of at least ±1%.
• Measurement method:
  • External diameter (OD): measure at a minimum of three locations ~1 m apart; each location requires two micrometer readings at 90° to each other.
  • Buffer tube/jacket thickness: measure radial thickness at thinnest and thickest points on a cross-section.
  • Concentricity: expressed as 100 × (minimum radial thickness / maximum radial thickness).
  • Mass: reported in kg/km and compared with product technical specification.
• Acceptance criteria: Final dimensional and mass values must conform to the relevant product standard or technical specification; individual readings must not exceed maximum specified values.

Applications

• Quality control and incoming inspection of aerospace optical cables.
• Verification for procurement and supplier acceptance testing.
• Laboratory test procedures for certification and compliance reporting.
• Design validation and R&D where dimensional conformity affects connectorization, routing or mechanical performance.
• Maintenance and overhaul checks where dimensional stability is required.

Who Uses This Standard

• Aerospace cable manufacturers and suppliers
• Test laboratories and quality assurance teams
• Aircraft systems engineers and integrators
• Procurement and conformity assessment bodies

Related Standards

• EN 3745-100 - Aerospace series - Fibres and cables, optical, aircraft use - Test methods - Part 100: General (normative reference).
• Applicable product standards or technical specifications for specific cable families (as cited in the product documentation).

Keywords: EN 3745-203:2008, fibre optic cable dimensions, aerospace standard, cable dimension test method, optical cables aircraft use, concentricity, external diameter, mass kg/km.