Photovoltaic Mounting Bracket Screws

1. Material

• Stainless Steel: High - grade stainless steel is a popular choice for PV mounting bracket screws. Alloys such as 304 and 316 stainless steel are commonly used. The chromium content in stainless steel forms a passive oxide layer on the surface, which provides exceptional corrosion resistance. This is highly beneficial as PV systems are frequently installed in outdoor settings where they are constantly exposed to moisture from rain, high humidity levels, and the corrosive effects of ultraviolet (UV) radiation from sunlight. For example, in coastal areas where the air contains salt particles, stainless steel screws can withstand the harsh environment without significant degradation for long periods.

• Galvanized Steel: Galvanized steel screws offer a more cost - effective alternative. They are made by coating low - carbon steel with a layer of zinc, either through hot - dip galvanization or electrogalvanization. The zinc coating acts as a sacrificial anode, protecting the underlying steel from rusting. When exposed to moisture, the zinc corrodes preferentially, sacrificing itself to prevent the steel from corroding. This makes galvanized steel screws suitable for many general - purpose PV installations in less - corrosive environments, such as inland regions with normal humidity levels.

2. Types

• Self - tapping Screws: Self - tapping screws are widely used in PV mounting applications. These screws have a sharp, tapered point and specially designed threads. When driven into the mounting material, which can be metal sheets (such as aluminum or thin - gauge steel used in mounting brackets) or certain composite materials, the screw cuts its own threads as it advances. This eliminates the need for pre - drilling in many cases, significantly speeding up the installation process. For instance, in a large - scale PV power plant where thousands of panels need to be installed, the use of self - tapping screws can save a substantial amount of installation time and labor costs.

• Machine Screws: Machine screws are another type commonly employed. They are designed to be used with pre - threaded holes or nuts. Machine screws offer more precise fastening and are often used when a higher level of accuracy and compatibility with other pre - fabricated components is required. In complex PV mounting structures where multiple components need to be assembled with tight tolerances, machine screws ensure a secure and reliable connection. For example, in custom - designed rooftop PV mounting systems where the brackets need to be precisely aligned with the building structure, machine screws provide the necessary precision.

3. Function

• Panel Fixation: The most fundamental function of PV mounting bracket screws is to firmly attach the photovoltaic panels to the mounting brackets. PV panels are delicate and need to be held in place securely to function optimally. The screws resist various external forces, including strong winds. In areas prone to high - velocity winds, such as open plains or mountainous regions, the screws must be able to withstand the dynamic loads exerted by the wind on the panels. They prevent the panels from being lifted or shifted, which could lead to misalignment and reduced energy generation.

• Structural Stability: In addition to panel fixation, these screws are crucial for maintaining the overall structural stability of the PV mounting system. They secure all the components of the mounting bracket together, creating a rigid framework. This is important as the mounting system needs to support the weight of the PV panels over an extended period, often 25 years or more in a typical PV installation. The screws also resist vibrations caused by factors like passing vehicles or wind - induced oscillations in the surrounding environment. By maintaining the integrity of the mounting structure, they ensure that the PV system can continue to operate efficiently and safely, maximizing the energy output and minimizing the risk of damage due to structural failures.