IEC 62153-4-12:2009

Overview

IEC 62153-4-12:2009 specifies an electromagnetic compatibility (EMC) test method - the absorbing clamp method - to measure coupling attenuation (also called screening attenuation) of connecting hardware used in analogue and digital communication systems. The standard covers testing a single part of connecting hardware (for example a wall outlet or plug) or a fully mated pair, and is intended to be read in conjunction with IEC 62153-4-5:2006.

Key topics and technical requirements

• Scope of measurement: Determination of coupling/screening attenuation at the near end using an absorbing clamp arrangement; typical set-up measures surface waves and common-mode coupling.
• Test equipment: Signal generator, absorbing clamp(s) with ferrite tube absorbers, current transformer, measuring receiver, reflector plate, test head and extension cables.
• Balun requirements: When measuring balanced connecting hardware, a balun or 180° splitter is required. Key balun parameters (30 MHz–1 GHz) include:
  • Primary impedance typically 50 Ω; secondary 100 Ω or 150 Ω depending on cable type
  • Operational attenuation ≤ 10 dB
  • Return loss ≥ 6 dB
  • Output signal balance ≥ 50 dB (30–100 MHz) and ≥ 30 dB (100 MHz–1 GHz)
• Test head and extension cables: Use cable types and terminations matching the connecting hardware under test. Extension cables must have the same nominal characteristic impedance, similar velocity of propagation, and the near-end terminating cable (including test head) should have operational attenuation < 1 dB up to 100 MHz.
• Calibration and measurement: Procedures include calibration of the absorbing clamp and verification of test set-up and measurement sensitivity. Measurement sensitivity must be at least 6 dB better than the applicable requirement limit.
• Test reporting: Standard specifies expression of results and required test report content for reproducibility and compliance documentation.

Applications and users

This IEC standard is practical for:

• Cable and connector manufacturers verifying EMC performance of plugs, outlets, patch cords, and connector assemblies.
• Independent test laboratories conducting compliance and quality assurance measurements for coupling or screening attenuation.
• EMC engineers and system integrators assessing susceptibility to common‑mode or surface‑wave coupling in communication systems.
• R&D teams optimizing connector designs, terminations and shielding for improved screening effectiveness.

Related standards

• IEC 62153-4-5:2006 (absorbing clamp method - related procedures)
• IEC 60050-726 (vocabulary for transmission lines/waveguides)
• IEC 61196-1 (coaxial communication cables)
• ITU‑T G.117 and O.9 (measurement of unbalance and balance)

Keywords: IEC 62153-4-12, coupling attenuation, screening attenuation, absorbing clamp method, EMC test method, connecting hardware, balun, test head, extension cables.