PV racks are anodized aluminum or galvanized steel with insulating surfaces; bolt pressure alone doesn't guarantee electrical continuity. A complete PV system needs equipotential grounding—linking module frames, rails, supports and the grounding grid—to prevent shock and divert lightning. Grounding fasteners are an overlooked but critical part.
Anodized, dacromet and zinc layers are insulating or high-resistance. Ordinary bolt pressure may leave metal parts electrically disconnected, so the rack has no continuous ground path. A lightning surge cannot then discharge, risking equipment and safety. Grounding parts scrape through coatings to establish metal-to-metal contact.
Toothed/star stainless washers sit between module frame and rail, or clamp and frame. When tightened, teeth pierce anodize and coatings to expose bare metal for low resistance. They must be stainless or tinned copper—plain galvanized iron corrodes and fails. Set grounding points per module frame by code.
Rail splices or thick coatings also need green-yellow braided copper jumpers fixed with grounding bolts. Cross-section is chosen by surge current and code—generally at least the specified copper size—with secure, corrosion-protected lugs. Grounding bolts connect supports to the main grid; scrape coating at the contact to meet resistance requirements.
Measure ground resistance after install per design and local code. Coastal/industrial sites inspect washer tightness and jumper corrosion; after wind or hail, check ground connections specially.
The solar fastener range supplies grounding washers, jumpers and bolts.