Profile rails (mounting rails) in photovoltaics

Material requirements and production

Mounting rails are made from high-quality aluminum using an extrusion process. An EN AW-6063 T66 alloy is usually used, which is characterized by its particular strength and corrosion resistance. The surfaces are anodized as standard, which creates an additional protective layer that protects the material from the effects of weather and corrosion. The typical layer thickness of the anodized layer is at least 15 micrometers.

Profile geometry and functional chambers

The cross-sectional geometry of modern profile rails is highly complex and the result of years of development. A typical profile has several specialized functional areas:

• The main chamber forms the load-bearing core of the profile and largely determines the static properties
• Side functional chambers serve to accommodate various connecting elements
• Integrated cable ducts enable clean and protected cable routing
• Special insertion grooves allow additional components to be installed without tools
• Support surfaces for module clamps ensure secure module installation

Dimensions and load capacity

Mounting rails are available in various heights and wall thicknesses, typically from 30mm to 80mm Height. The choice of the correct profile size depends on:

• The expected snow and wind loads
• The maximum spans between the support points
• The weight of the modules used
• The type of installation (single or cross rail system)

The load-bearing capacity is determined by the section modulus and the moment of inertia of the profile. These values ​​must be documented by the manufacturer in technical data sheets.

Special designs of profile rails

Depending on the area of ​​application, various special solutions exist:

• Light profiles for small spans and loads
• Heavy-duty profiles for large spans and high snow loads
• Elevator profiles with increased support surface for east-west systems
• Trapezoidal profiles for direct mounting on trapezoidal sheets
• Triangular profiles for raised systems

Connection technology

Modern Profile rails have sophisticated connection systems:

• Internal rail connectors for front-end extension
• Expansion connectors to compensate for thermal length changes
• Cross connectors for multi-layer rail systems
• Quick connectors for tool-free assembly

Standards and certifications

Mounting rails for photovoltaic systems must comply with various standards:

• Eurocode 9 for the design of aluminum structures
• DIN EN 1090 for the design of steel and aluminum structures
• DIBt approvals for building inspection use
• Special product standards of the solar industry

Planning and dimensioning of the mounting rail

The correct design of a rail system requires detailed calculations taking into account:

• The local wind loads according to DIN EN 1991-1-4
• The snow load zone according to DIN EN 1991-1-3
• The building height and terrain category
• The module sizes and weights
• The fastening point spacing
• The thermal Linear expansion

Assembly and installation of profile rails

Various aspects must be taken into account during assembly:

• Observance of the maximum spans between the support points
• Correct alignment and screwing of the connecting elements
• Taking temperature expansion into account by means of appropriate expansion joints
• Clean cable routing in the cable ducts provided
• Observance of the prescribed tightening torques for screw connections

The longevity and reliability of a photovoltaic system depends largely on the quality and correct dimensioning of the mounting rails used. Careful planning and professional installation are therefore essential for the long-term success of the system.