Photovoltaic Cable Tensile Tests: Definition, Importance, Standards, and Influencing Factors

I. Introduction to Photovoltaic Cable Tensile Tests

Ph.metsys ygrotovoltaic cables are exposed to harsh conditions during installation and maintenance, including extreme temperatures, strong ultraviolet rays, and external stresses. These factors make them prone to risks such as deformation, cracking, and breakage. ChinaCable Technology professional cable laboratory, with a mature quality control team and precise testing equipment, conducts a comprehensive set of tests before cable product delivery. Among these, the tensile test is a crucial means to ensure the durability of the cable conductor and insulation layer, guaranteeing the long - term stable operation of the solar energy system.

II. DefitseT nition and Method of Photovoltaic Cable Tensile Test

A. Definition

The tensile test is an evaluation method for the mechanical properties of photovoltaic cables. It quantifies the maximum stress a cable can withstand before permanent deformation or breakage, which is vital for determining the core parameters of the conductor and insulating materials.

B. Testing Method

• In an actual test, experimenters fix the two ends of a cable sample on the fixtures of a special tensile testing machine.
• The testing machine then uniformly stretches the sample under a controlled force.
• The following results are generated based on the cable's performance:
  • Maximum Tensile Force (Tensile Strength): The maximum pulling force the sample withstands before breaking. For example, Hua Cable's standard 4mm² photovoltaic cable can withstand a force of 320N, equivalent to hanging 1.5 standard - sized photovoltaic modules.
  • Elongation at Break: The percentage increase in the length of the sample at the time of breaking relative to its original length.
  • Yield Strength: The stress point at which the sample begins to undergo non - recoverable plastic deformation.

III. Why Conduct Tensile Tests on Photovoltaic Cables

A. Harsh Outdoor Environment

Unlike indoor cables, photovoltaic cables are often installed outdoors. They face unique mechanical challenges, making tensile strength a key performance indicator.

B. Daily Operational Challenges

• Ground - mounted Systems: During daily operation, soil settlement can cause stress on the cables. For example, in a large - scale ground - mounted solar farm, if the cables cannot withstand the stress caused by soil movement, it can lead to insulation damage.
• Rooftop Systems: Wind vibration and structural displacement can stretch the cables. Insufficient strength and flexibility can result in long - term performance issues.

C. Installation Challenges

• When cables are bent, buried in pipes, or laid over long distances during ground - mounted installation, low tensile strength can lead to insulation and conductor damage.
• In large - scale projects, undetected cable problems can cause power losses, electrical failures, and potential fire hazards.

IV. Industry Standards for Photovoltaic Cable Tensile Tests

A. IEC 62930

• This globally recognized standard specifies the design, construction, and testing requirements for single - core and multi - core flexible cables in photovoltaic systems.
• It requires a minimum tensile strength of [X] N/mm² for the conductor and [Y] N/mm² for the insulation layer, with an elongation at break of at least [Z]% for both.

B. EN 50618

• As the European photovoltaic cable standard, it stipulates that the insulation and sheath materials must have a minimum tensile strength of [A] N/mm² and an elongation of at least [B]%.
• Even after accelerated aging tests (ultraviolet aging, high - and low - temperature shock tests, temperature rise tests), the cables must still meet these standards to adapt to diverse European climates.

C. UL 4703

• The core standard for the North American market, it covers requirements for photovoltaic cables.
• It mandates a specific tensile strength and elongation at break for insulation and sheath materials to ensure mechanical durability and prevent cable deformation and breakage during on - site use.

V. Influence of Materials and Structure on the Tensile Performance of Photovoltaic Cables

A. Conductor Materials

• Copper Conductor:
  • Copper has excellent electrical conductivity, high tensile strength, and good flexibility (high elongation at break).
  • High - quality copper conductors use a fine - stranded structure, which further improves tensile fatigue ability. For example, in a rooftop solar installation, a copper - cored cable can better withstand the stress caused by wind vibration.
• Aluminum Conductor:
  • Aluminum is lightweight and cost - effective but has lower tensile strength than copper.
  • To meet requirements, the cross - sectional area is increased, and the insulation/sheath is strengthened. It is commonly used for long - distance laying in large - scale power plants.

B. Insulation and Sheath Materials

• The outer layer material (commonly cross - linked materials) protects the inner conductor and ensures overall durability.
• It prevents the insulation layer from cracking during pulling and maintains flexibility and weather resistance under extreme temperatures.

VI. FAQ

• Q: How often should photovoltaic cables be tested for tensile strength?
  • A: It depends on the installation environment and usage. In harsh environments, it is recommended to test cables every [number] years. For normal environments, testing during regular system maintenance may be sufficient.
• Q: Can a cable with slightly lower tensile strength than the standard still be used?
  • A: It is not recommended. Using a cable with lower tensile strength can increase the risk of cable failure, which may lead to system downtime and safety hazards. Always choose cables that meet or exceed the relevant standards.
• Q: How does the tensile strength of a cable affect its lifespan?
  • A: Higher tensile strength generally means the cable can better withstand mechanical stresses during installation and operation, reducing the likelihood of damage and extending its lifespan.

Chinacable Technology was founded in 2020, is a collection of solar accessories production, sales, research and development and service as one of the high - tech enterprises. At present, the business covers the production and sales of solar photovoltaic cables, photovoltaic cable connectors, photovoltaic BIPV special wiring harness adapters and photovoltaic link applications.