Overview
IEC 62153-4-8:2018 is an IEC test-method standard for measuring capacitive coupling admittance, capacitive coupling impedance and coupling capacitance of metallic communication cables and other passive components. The second edition (2018) updates the 2006 edition and introduces a triaxial test set-up (aligned with IEC 62153-4-3 transfer-impedance methods) and modern measurement instrumentation such as the vector network analyser (VNA) in place of older capacitance-bridge or pulse-generator techniques. The standard is focused on electromagnetic compatibility (EMC) aspects of cable screening, particularly where capacitive coupling through screen holes (e.g., loose single-braids) can be significant.
Key Topics and Requirements
- Scope: Applies to metallic communication cables; specifies test procedures to determine through capacitance and derive capacitive coupling admittance/impedance.
- Triaxial set-up: Uses a triaxial arrangement similar to the transfer-impedance measurement (IEC 62153-4-3) to separate inner and outer circuits and control measurement environments.
- Measurement parameters: Defines how to obtain coupling capacitance, capacitive coupling admittance and capacitive coupling impedance from measured through-capacitance.
- Instrumentation: Recommends use of a vector network analyser (VNA) for frequency-domain measurement; replaces capacitance bridge and pulse methods used in the prior edition.
- Test procedures: Covers sample preparation, coupling length selection, cut-off frequency considerations, calibration, measurement sequence and evaluation of results.
- Reporting: Requires documented test reports including setup, calibration, measured admittance/impedance, and relevant environmental/test conditions.
- Special cases: Emphasises testing for cables with loose single-braids or screens with holes where capacitive coupling may not be negligible.
Applications and Who Uses This Standard
- Cable manufacturers validating EMC screening and shielding performance.
- Third‑party test laboratories performing compliance and qualification testing for communication cables and passive components.
- EMC engineers assessing coupling paths and interference risks in cable assemblies, data centers and telecom infrastructure.
- Designers of screened cables and connectors who need to quantify capacitive coupling effects for system-level EMC mitigation.
- Compliance officers and procurement teams specifying testable EMC performance criteria for cable products.
Keywords naturally integrated: IEC 62153-4-8:2018, capacitive coupling admittance, capacitive coupling impedance, coupling capacitance, triaxial set-up, vector network analyser, EMC testing, metallic communication cables, transfer impedance, cable screening.
Related Standards
- IEC 62153-4-3 - Surface transfer impedance (triaxial method)
- IEC 62153-4-1 - Introduction to EMC screening measurements
- IEC 61196-1 - Coaxial communication cables - Generic specification
- IEC 60050-726 - IEV terms for transmission lines and waveguides
This standard provides a practical, repeatable methodology for quantifying capacitive coupling in metallic cables-essential when screening imperfections may affect EMC performance.