How to choose the solar galvanized steel ground screw pile?

Choosing the right galvanized steel ground screw pile for solar installations requires careful consideration of technical, environmental, and project-specific factors. Here’s a step-by-step guide:

1. Understand Soil Conditions (Most Critical!)
   Soil Type: Sandy, clay, loam, or rocky? Use a soil report or manual testing (e.g., hand auger) to assess.

Bearing Capacity: Soft soils need longer/heavier-duty screws; rocky soils may require specialized helix designs.

Water Table & Frost Line: Ensure piles extend below the frost line and avoid corrosion-prone waterlogged zones.

2. Calculate Structural Loads
   Vertical Load: Weight of panels + mounting structure + snow/wind pressure.

Lateral/Uplift Load: Wind uplift forces (dominant in solar). Use ASCE 7 or local codes for wind/snow load calculations.

Safety Margin: Add 25–50% extra capacity for safety (e.g., 5,000 lb pile for a 3,500 lb actual load).

3. Pile Specifications
   Diameter & Length:

Common diameters: 76mm (3″), 89mm (3.5″), 114mm (4.5″).

Typical lengths: 1m–3m+ (deeper for unstable soil/high loads).

Helix Design:

Single-helix for stable soils.

Multi-helix (2–4 blades) for weaker soils or high uplift resistance.

Shaft Thickness: ≥4mm for durability; ≥5mm in corrosive/high-load sites.

4. Corrosion Protection
   Galvanization: Hot-dip galvanized (HDG) coating ≥80μm.

Supplemental Protection: Use zinc-aluminum coatings (e.g., ZM-310) or polymer sleeves in highly corrosive soils (pH <5 or >10, high salinity).

5. Project Logistics
   Installation Equipment: Confirm compatibility with hydraulic drivers (e.g., torque requirements: 2,000–6,000 Nm).

Lead Time & Supply: Ensure timely delivery for project schedules.

6. Cost vs. Quality Balance
   Avoid underspecifying to save costs—overloading risks system failure.

Compare $/kN load capacity, not just per-unit cost.

Quick Selection Checklist
Factor Recommendation
Soil Type Test soil; multi-helix for weak soils.
Load Capacity Include 1.5x safety factor for wind/snow.
Coating Thickness ≥80μm HDG + extras in harsh environments.
Shaft Thickness ≥4mm (standard); ≥5mm (high-load/corrosive).
Installation Torque monitoring during install (verify capacity).

Example Sizing

Residential Rooftop Equivalent (10 kW):
76mm–89mm diameter × 1.5m–2m piles (single-helix, stable soil).

Commercial Carport (100 kW):

89mm–114mm × 2.5m–3.5m piles (multi-helix, clay soil).

When to Consult Experts
Complex Sites: Rocky soil, slopes >10°, or high seismic zones.

Large Projects: Utility-scale farms need geotechnical surveys + engineered designs.

Our company has developed different series of screws to meet varied applications. The flange solar ground screws is installed with a number of specific aids and machines, perfectly perpendicular at the exact point after minutes. As per practical requirements, the solar mounting ground screw pile is able to be planned and customized in the factory to avoid welding and cut on the spot, saving your time and cost.

More details for you. Contact us Email：[email protected]