Square Steel Tube for Solar Mounting

Why Steel Tubes Are Crucial in PV Systems?

In any photovoltaic (PV) installation, the mounting system is what keeps the modules in place for 25+ years of outdoor exposure. Square steel tubes form the structural backbone of most heavy-duty and ground-mounted PV systems — from utility-scale solar farms to commercial rooftop arrays and carport structures. The following Q&As explain why they matter, how they are specified, and what to consider when sourcing them.

1. What makes steel tubes so important in PV systems?

Steel tubes carry four non-negotiable jobs in a PV array:

• Structural support — holding the weight of the modules against gravity over decades.

• Wind and snow load resistance — resisting uplift, drag, and accumulated snow loads.

• Long-term dimensional stability — keeping panel tilt and alignment true across 25+ years of thermal cycling.

• Interface compatibility — providing a rigid anchor for clamps, brackets, and module frames.

Compared with thin aluminum rails, square steel tubes can be produced in much larger cross-sections (40×40mm up to 140×140mm and beyond), which is essential when the span between foundations is long, or when the design must meet strict wind and snow codes such as Eurocode or AS/NZS 1170.

2. What loads must steel tubes in PV systems handle?

A properly specified steel tube for solar mounting is typically rated to handle:

• Max wind load: up to 60 m/s (≈ 216 km/h) — covering typhoon-zone and coastal installations.

• Max snow load: up to 1.4 kN/m² — equivalent to roughly 140 kg of snow per square meter.

These ratings apply to the finished structure, so the steel tube itself must keep enough margin in both bending and torsion. That’s why our SPC-SHS profile uses SD350-grade steel with controlled wall thickness — the structure stays within elastic limits under the worst expected load combination.

3. What material and coating should I choose?

For solar mounting in outdoor conditions, the coating matters as much as the base steel grade. For most PV applications, ZAM (Zinc-Aluminum-Magnesium) coated steel is now the preferred choice — it offers superior corrosion resistance compared with standard galvanizing, especially in harsh or coastal environments where salt spray, humidity, or agricultural chemicals attack the steel.

Our SPC-SHS profile uses SD350-grade steel with ZAM275 coating — a balance of strength, formability, and long-term corrosion protection that suits the majority of utility, commercial, and carport installations.

4. Which tube sizes are most common?

Most PV steel structures use one of these profiles:

Profile	Typical role in PV systems
40×40mm	Light rails, purlins, cross-bracing
50×50mm / 60×60mm	Mid-duty rails, small ground-mount posts
80×80mm / 100×100mm	Main posts for ground-mount systems
120×120mm / 140×140mm	Heavy utility-scale or carport main columns

The right size depends on span, panel area, wind zone, and snow zone — not just module count. Larger profiles are chosen when foundations are spaced further apart or when the local code demands higher safety factors.

5. What wall thickness do I need?

For solar mounting, wall thickness usually falls between 1.8mm and 3.0mm:

• 1.8–2.0mm — light commercial and small ground-mount.

• 2.0–2.5mm — standard ground-mount and carport applications.

• 2.5–3.0mm — utility-scale, high wind/snow zones, or longer spans.

Thicker walls cost more and add weight, so specifying the minimum thickness that satisfies your structural calculation is the smart move. Over-specifying steel is one of the most common sources of unnecessary cost in PV mounting projects.

6. Where exactly are steel tubes used in PV systems?

Three primary application areas:

• Ground-mount systems — as vertical posts driven into the ground, mounted on ground screws, or fixed to concrete foundations.

• Solar carports — as main frame columns and roof purlins, carrying both the panels and the canopy’s own weight.

• Industrial rooftop racking — when the roof structure demands heavier support than standard aluminum rails can provide.

In all three, the steel tube is the load path. Everything else — module clamps, mid-clamps, end-clamps, splice connectors, L-feet — connects to it.

7. Why use square tubes instead of round tubes or C-channels?

Square tubes win on three points that matter in PV mounting:

• Torsional rigidity — a closed square section resists twisting far better than an open C-channel, which is critical under uneven wind loading.

• Easier fabrication — flat faces are simple to drill, weld, and bolt to; brackets sit flush without saddle plates.

• Better stackability and shipping — square tubes pack efficiently into standard 20ft/40ft containers, reducing freight per kilogram of steel delivered to site.

For most PV mounting, the square profile gives you the best balance of strength, ease of assembly, and logistics cost.

8. Can the steel tubes be customized for my project?

Yes — and for serious projects you should. Typical customization options include:

• Cut-to-length — standard 6m lengths can be cut to your exact spec to reduce on-site waste and labor.

• Pre-punched holes — for bolted connections between posts, rails, and brackets, eliminating field drilling.

• Higher coating mass — extra ZAM thickness for coastal or highly corrosive sites.

• Color coating — for architectural integration on visible carports or commercial rooftops.

• OEM/ODM — private labeling and packaging for distributors and integrators.

If you have a Bill of Quantities (BOQ) or a structural drawing, send it over and we can propose a per-piece cut list and hole pattern before production starts.

9. What information do I need to provide for an accurate quote?

To quote accurately, please share:

• Structural drawings or BOQ — quantities, sizes, lengths, hole patterns.

• Project site conditions — wind zone, snow zone, soil type, corrosivity category.

• Applicable codes — Eurocode, AS/NZS 1170, IBC, JIS, or local standards.

• Hole pattern requirements — pre-punched at the mill, or drilled on site.

• Packaging preference — bundles, crates, or container-optimized packing for international shipping.

The more complete the brief, the faster and tighter our pricing.

10. Are steel tubes compatible with standard PV racking accessories?

Yes. Square steel tubes work with the full range of standard solar mounting hardware — including module clamps, mid-clamps, end-clamps, splice connectors, L-feet, ground screws, and concrete anchors. Because the cross-section is standardized and the wall thickness is uniform, brackets from virtually any racking supplier can be specified to fit the same tube.

This makes steel tubes a flexible choice when you are mixing suppliers or assembling a hybrid system.

 

Steel tubes aren’t just one option among many in a PV system — they are the load-bearing foundation that lets the rest of the structure do its job for 25+ years. Choosing the right size, wall thickness, and coating (especially ZAM275 for harsh sites) is what separates a mounting system that lasts from one that becomes a long-term maintenance liability.

If you have a project in mind, send us the structural drawing or BOQ and we’ll quote within 24 hours.

Can Square Steel Tube be Solar Mounting Pole?

–Dear Sirs SOLAR PARTS, my name is Daniel Natividad, General Manager of SCIP.

 Our company specializes in the execution of automation and power control

 projects in low and medium voltage.

Our operations are primarily located in northern Peru, serving the mining,

cement, water, and paper sectors. We are currently implementing a solar

power, so we need to acquire square  steel tube for solar mounting single pole.

We request a quote for the following:

1936     Units.    Single Pole Solar Mounting Structure for 1 Panel

                               Tilt Angle: 15°

Pole Height: 4500mm

Wind speed: 10m/s

Foundation. Concrete

40          Units.    Single Pole Solar Mounting Structure for 2 Panel

                               Tilt Angle: 15°

Pole Height: 4500mm

Wind speed: 10m/s

Foundation. Concrete

Panel Model: JKM650 (Jinko Solar 650W)

Quote FOB

Please confirm receipt of this message.

Best Regards.

BR.

Daniel E. Natividad Caro

 

 

— Hello Daniel,

Yes our Square Steel Tube for Solar Mounting is widely used for solar mounting structures as Pole/Purlin/Beam….

With high quality ZAM275 material, the system is designed for a service life of 25+ years, matching the standard warranty period of most PV modules. Stainless steel fasteners can be specified for coastal or high-humidity environments.

We offer full OEM/ODM support: custom pipe dimensions, wall thickness, tilt angles, special coating colors (e.g., powder-coated black), and module layouts. We also print your logo and provide custom packaging. Share your drawings or site conditions and our engineers will tailor the design.

What is Zn-Al-Mg coating and why is it better than galvanized?

Zn-Al-Mg is a zinc-aluminum-magnesium alloy coating (EN 10346 ZM system). Compared with traditional hot-dip galvanized pure zinc, it offers 2–10× longer salt-spray life and a self-healing effect: when the tube is cut, drilled or scratched, the coating migrates to protect the exposed steel. For coastal and typhoon-zone solar plants it means fewer corrosion failures over the project lifetime.