A solar grounding clip (or earthing clip) is a critical safety device that creates an electrical path between the solar panel frame and the mounting rail, directing any fault current safely to the ground. Its effectiveness depends entirely on correct installation.
Core Principle of Operation
Before installation, understand its function: The sharp, piercing teeth on the clip are designed to penetrate the non-conductive anodized layer on the aluminum panel frame and mounting rail. This establishes a bare metal-to-metal contact, ensuring a low-resistance path for electrical current.
Standard Installation Steps
Step 1: Preparation and Positioning
Identify Components: Ensure you have the grounding clips, corresponding mid-clamps (or end-clamps), and bolts.
Locate Installation Point: Place the solar panel onto the mounting rails. The grounding clip is typically installed beneath the panel frame, at the point of contact with the rail, and is integrated into the mid-clamp installation process.
Step 2: Placing the Grounding Clip
Orient the Clip: Position the clip so its "U" shaped or slotted opening faces the mounting rail.
Position the Clip:
Method A (Integrated with Mid-Clamp): This is the most common method. Slide the clip's dedicated slot onto the shank of the mid-clamp bolt (e.g., M8 size). Then, place the entire assembly (clamp + clip) between two adjacent panel frames, directly on the rail.
Method B (Direct Placement): For some designs, the clip is first placed directly between the panel frame and the rail before the clamp is positioned over it.
Step 3: Tightening and Locking
Hand-Tighten: Thread the nut onto the clamp bolt by hand to hold all components (panel frame, clip, rail, clamp) in alignment.
Final Torque: Using a torque wrench, tighten the nut to the manufacturer's specified value (commonly between ~12-16 Nm).
The Critical Action: As you torque the bolt, the pressure forces the clip's sharp teeth to bite through and pierce the anodized coatings on both the panel frame and the rail. This creates the essential electrical connection.
Step 4: Final Inspection
Visual Check: Ensure the clip is seated flat and is not bent or distorted.
Continuity Test (Recommended): Use a multimeter to measure the electrical resistance between a panel frame and the rail. A properly installed clip will show a very low resistance value (typically < 1 ohm).
Key Considerations & Best Practices
Never Omit the Clip: Do not skip the grounding clip to save time or cost. It is a life-safety device required by electrical codes.
Compatibility: Verify that the clip is compatible with your specific panel frame thickness, rail profile, and clamp type.
Torque is Critical: Always use a torque wrench. Under-torquing can lead to a high-resistance connection that may overheat; over-torquing can damage the frame, clamp, or clip.
Corrosion-Resistant Material: Ensure clips are made from stainless steel (e.g., SS 304 or 316) to withstand harsh outdoor environments.
Complete the Grounding System: Remember, the clip is just one link in the chain. Ensure all rail sections are bonded together, and the entire array is connected to a grounding electrode via a properly sized grounding conductor.
Noted: This article is for industry discussion purposes only. Please ensure that a professional engineering team is responsible for installation!
