Fiber optic cables with electrical conductors must meet IEC 60794-1-2:2021 requirements for withstand voltage testing, ensuring insulation integrity under specified voltage stress.

Applicable Standard

The primary standard for fiber optic cable withstand voltage testing is IEC 60794-1-2:2021, which applies to optical fiber cables used in telecommunications and hybrid cables containing both optical fibers and electrical conductors. This standard defines general test requirements, methodologies, and performance criteria for all cable types within the IEC 60794 series .

Test Objectives

The withstand voltage test aims to verify that the cable insulation can resist electrical stress without breakdown. For fiber optic cables with metallic elements, this ensures that the cable can safely operate in environments where electrical surges or faults may occur. The test identifies weak points in insulation and confirms the cable's long-term reliability .

Test Methodology

• Voltage Application: The cable is subjected to a specified AC or DC voltage, typically higher than the nominal operating voltage, for a defined duration. The exact voltage level depends on the cable design and intended application.
• Duration: The voltage is applied for a sufficient period to detect insulation weaknesses. While IEC 60794-1-2 does not prescribe a single duration, industry practice often follows 30–60 minutes for acceptance tests, similar to power cable testing principles .
• Monitoring: The test may include monitoring for partial discharge or insulation breakdown. Any failure requires repair or rejection of the cable section, followed by retesting to ensure compliance .

Equipment Requirements

• Precision Voltmeter: Must meet high accuracy standards (e.g., JIS Class 1.5 or equivalent) to measure applied voltage and detect breakdowns .
• Output Capacity: The test equipment should provide sufficient power to maintain the test voltage without significant drop, typically at least 500 VA for small-scale tests .
• Controlled Voltage Ramp: The voltage must be gradually increased to the target level to avoid sudden stress that could damage the cable prematurely .

Performance Criteria

• No Breakdown: The cable must withstand the applied voltage without insulation failure.
• Documentation: Test results must be recorded, and any corrective actions must be documented. Retesting is required after repairs to confirm compliance .
• Environmental Considerations: Tests are generally conducted under controlled temperature and humidity conditions to ensure repeatability and reliability of results .

Summary

Fiber optic cables with electrical conductors are tested according to IEC 60794-1-2:2021 to ensure insulation integrity under electrical stress. The test involves applying a specified voltage for a defined period, monitoring for breakdown, and documenting results. Proper test equipment, controlled voltage application, and adherence to standard procedures are essential to verify that the cable meets safety and performance requirements .