EN 50065-4-2:2001/A2:2005

Overview

EN 50065-4-2:2001/A2:2005 is an amendment to the CENELEC safety standard for low-voltage decoupling filters used in signalling on low-voltage electrical installations. The amendment extends the published title and scope to explicitly cover the frequency ranges 3 kHz to 148.5 kHz and 1.6 MHz to 30 MHz. No technical changes to the body were required to include the extended band; the update clarifies safety scope and adds targeted requirements and proposals to strengthen protection and testing practices.

This safety standard was prepared by SC 205A (Mains communicating systems) of Technical Committee TC 205 (Home and Building Electronic Systems). It applies to decoupling filters used in building mains signalling and supports consistent national implementation across CENELEC members.

Key Topics

• Scope extension: Title and scope amended to include 1.6 MHz–30 MHz in addition to the original 3 kHz–148.5 kHz band, without technical modification to the core requirements.
• Protection against electric shock: A new requirement addresses static discharge for filters containing capacitors > 0.1 µF between line conductors. The resulting static voltage must fall below DC 120 V within 5 seconds after disconnection from the power supply.
• Insulation resistance and dielectric strength: Test arrangements clarified so electronic components between live parts of different polarity are disconnected for certain tests; editorial corrections to measurement wording were also made.
• Components and fault considerations: For filters with rated currents ≥ 40 A it is proposed to consider a minimum prospective fault current of 6 000 A for component selection and short-circuit protection design.
• Protection against short-circuit: Corresponding proposal to account for the 6 000 A prospective fault current for higher-rated filters.

Applications

EN 50065-4-2 is relevant to manufacturers, designers, test laboratories and safety engineers working with:

• Building and residential mains signalling systems using powerline communication
• Design and certification of low-voltage decoupling filters for EMC and signalling isolation
• Safety assessments addressing electric shock, dielectric strength, and short-circuit robustness

Practical benefits include clearer safety expectations for capacitor discharge behavior, consistent test practices for insulation and dielectric strength, and recommended fault-current considerations for high-current filter designs.

Related Standards

• Other parts of the EN 50065 series covering signalling frequency bands and functional requirements
• CENELEC TC 205 / SC 205A deliverables on mains communicating systems and HBES safety

For implementation, refer to the published amendment text for exact clause changes and the national adoption timelines set by CENELEC. The amendment ensures harmonised safety language across member bodies while preserving the original technical provisions of Part 4-2.