Decoding the AD7/AD8 water resistance of SOLARFLEX® cables

1.1 Potential and challenges for the solar industry in Vietnam

The potential for solar energy development in Vietnam is enormous, thanks to its location near the equator and sunny regions such as the southern Central Coast provinces. However, alongside the potential for sunlight, there are other challenges during the rainy season. Specifically, from early May to November, solar energy projects will encounter problems with damaged electrical cables due to direct contact with water or even immersion in rainwater.

1.2 Risks if DC cables are not waterproof

For electrical cable lines in photovoltaic systems, which are frequently exposed to rainwater and harsh outdoor environments, the following issues must be addressed:

1. The cable has been damp for a long time, leading to oxidation of the conductor core.
2. Degraded insulation increases the risk of electrical leakage and safety hazards.
3. Reduced system performance, inverter error.

Given the above situation, in order to help limit unwanted losses and electrical incidents, electrical cable products have been researched and supplemented with water resistance standards to enable the cables to function well in high humidity conditions for a certain period of time. Among these, the AD7/AD8 standard related to the water resistance of cables should also be included as one of the important criteria when selecting DC electrical cables.

Explore the characteristics of AC and DC cables for photovoltaic systems

3.1 TÜV certification

In the solar energy sector, international certifications play a crucial role in ensuring product quality and reliability. One of the most reputable organizations is TÜV (Technischer Überwachungsverein – German Technical Inspection Association). Products certified by TÜV have undergone rigorous testing for safety, quality, and durability in accordance with European standards.

3.2 AD7 and AD8 standards according to TÜV standards

Regarding the water resistance of cables, TÜV currently only recognizes the AD7 standard, which allows cables to withstand temporary submersion (e.g., approximately 1 meter for 30 minutes) without affecting their functionality. This is a common and highly practical level, especially in environments that are frequently exposed to heavy rain or short-term flooding.

Meanwhile, AD8 is defined as the water resistance level for prolonged and complete submersion in water (equivalent to IPX8). However, to date, the DIN EN 50565-2 standard has not provided a clear testing procedure for AD8, so TÜV does not certify AD8. Some manufacturers may advertise "AD8 certified," but this is only their own claim and is not officially recognized by international certification organizations.

Therefore, when selecting DC cables for solar power projects, it is essential to distinguish between TÜV-certified standards (AD7) and advertising claims about AD8. Choosing the correct certified cable type will help you minimize risks, ensure safety, and guarantee long-term system performance.

Discover HELUKABEL's range of TÜV-certified DC cables

At HELUKABEL, we offer the SOLARFLEX®-X H1Z2Z2-K series, a specialized DC cable for solar energy systems, certified by TÜV for water resistance according to AD7 and tested under conditions approaching AD8.

Datasheet of SOLARFLEX-X_H1Z2Z2-K DC cables

Key advantages of SOLARFLEX®-X H1Z2Z2-K

• Superior water resistance: meets DIN VDE 0285-525-2-21 / DIN VDE EN 50525-2-21 Appendix E standards.
• Flexible application: Since the standard AD7 does not clearly define the duration of water immersion, the cable can be used in areas subject to flooding, heavy rain, or temporary flooding, provided that conditions allow it to dry out again.
• UV & weather resistant: ensures reliable outdoor operation in harsh environments.
• Halogen-free, flame-retardant: enhances system safety.
• Can be buried directly in the ground: Typically, electrical cables that need to be buried in the ground require protective conduits, but using conduits makes it difficult to check signal transmission and repair in case of problems. Therefore, cables buried directly in the ground save on the cost of protective conduits and are easier to repair when necessary.
• Tinned conductors: help reduce the risk of oxidation when the wire comes into contact with water.

With water resistance meeting international standards, combined with multiple safety features and high durability, SOLARFLEX®-X H1Z2Z2-K is a reliable choice for solar power projects in Vietnam, especially in harsh weather conditions during the rainy season.