Introduction: Small Components, Big Impact

In PV mounting systems, module clamps and bolts are the core fasteners that connect PV modules to the mounting structure. Although small in size, they carry the “fixing mission” of the entire power plant – ensuring that modules remain stable under harsh conditions such as strong winds and snow loads for over 25 years. In 2024, as PV module power continues to increase, module sizes grow, and bifacial and flexible modules become more common, technological innovations in clamps and bolts have also seen new breakthroughs.

Part One: PV Module Clamps

Clamps are connectors that secure PV modules to rails or roof structures through clamping force, requiring no drilling into the module frame.

Main Types:

Core Advantages:

Representative Products:

Clenergy Zano Mid Clamp: AL6005-T5 aluminum alloy, integrated grounding pins, fits 28-42mm frames, recommended torque 13-16 N·m

VEVOR Adjustable End Clamp: 35-50mm adjustment range, suitable for flat roofs, RVs, boats, and other scenarios

S-5! Protea™ Rail-less Clamp: Designed for trapezoidal metal roofs, integrated grounding, FM 4478 certified

Part Two: PV Module Bolts

Bolts achieve secure connections between modules and structures by passing through pre-drilled holes in module frames or mounting structure connections.

Main Types:

Core Advantages:

Technical Parameters (Stainless Steel Hex Bolt):

Part Three: Clamps vs. Bolts – Comprehensive Comparison

Part Four: Selection Recommendations

Part Five: 2024 Technology Trends

1. Integrated Grounding Becomes Standard

In 2024, mainstream clamp products generally integrate grounding functionality (e.g., Clenergy Zano, S-5! Protea™). Built-in grounding teeth pierce the oxide layer on the module frame, ensuring reliable electrical continuity and eliminating the need for separate grounding wires, significantly simplifying installation.

2. Adjustable Designs Widen Compatibility

Adjustable clamps with 35-50mm frame thickness compatibility (e.g., VEVOR) are becoming more common, accommodating the growing variety of module frame designs and simplifying inventory management for installers.

3. High-Strength Materials

The use of AL6005-T5 aluminum alloy and SUS304/SUS316 stainless steel ensures that clamps and bolts can withstand the higher loads imposed by larger, heavier modules and extreme weather conditions.

4. Anti-Loosening Innovations

Serrated washers, double nuts, and pre-applied anti-loosening coatings are increasingly used to ensure long-term reliability under wind-induced vibration and thermal cycling.

5. Torque Control Tools

The use of torque wrenches and torque-limiting tools has become standard practice to ensure consistent clamping force and prevent over-tightening that could damage modules or under-tightening that could lead to loosening.

Part Six: Quality Inspection

In a Nutshell

PV module clamps and bolts each have their distinct advantages. Clamps offer faster installation, no frame penetration, and integrated grounding, making them ideal for rooftop and rail-less applications. Bolts provide higher strength, lower cost, and mature standardization, making them the preferred choice for large-scale ground power plants. In 2024, technological innovations in both categories – from integrated grounding in clamps to advanced anti-loosening designs in bolts – are ensuring that PV modules remain securely fastened for 25 years and beyond.