Solar Mounting Wind & Snow Load Calculator
Select a design standard (AS/NZS 1170.2, ASCE 7-22, EN 1991-1-4 or manual), enter your wind region, roof type and array size — the calculator returns governing support spacing and a complete preliminary BOS BOM covering solar panels, mounting, PV cables, connectors, combiner boxes, DC/AC protection and grounding. Use the output as an RFQ starting point and send to OmniSol for supplier matching and consolidated export shipment.
System size
4.8 kWp
12 panels
DC strings
1 strings
12 panels/string
Governing spacing
1600 mm
Wind
Cable selection
6mm2
AC 6mm2
Wind pressure
0.911 kPa
Support spacing
1600 mm
Mounting output
480 mm
Regional spacing comparison
Spacing is capped at 1600 mm for preliminary use. Final clamp spacing still needs project-specific structural review.
System summary
System size
4.8 kWp
12 modules
DC strings
1
12 panels/string
AC current
22.0 A
1-phase, MCB 32A
Cable sizes
6mm2
AC 6mm2
Preliminary OmniSol BOS BOM - For Quote Request
12 panels | portrait | 4.8 kWp | 1 strings | 1000V DC | 1-phase AC
| SKU | Description | Qty | Unit |
|---|---|---|---|
| Solar panels | |||
| PANEL-TOPCON-400W-TBC | Optional solar panel sourcing, 400W class; brand, dimensions, certification and warranty to be confirmed | 12 | pcs |
| Mounting hardware | |||
| OS-MK-SC-30 | Seam clamp / L-foot interface kit | 24 | pcs |
| OS-RL-4200-40 | Aluminum mounting rail 4200 mm, project-cut to layout | 8 | pcs |
| OS-CL-MID-35 | Mid clamp kit for 30-35 mm module frame | 20 | pcs |
| OS-CL-END-35 | End clamp kit for 30-35 mm module frame | 8 | pcs |
| OS-BOLT-M8-30 | M8 x 30 mm bolt and rail nut set | 76 | sets |
| OS-SPLICE-40 | Internal rail splice connector | 4 | pcs |
| DC cables | |||
| OS-PNT-H1Z2Z2-K-06-RED | Preliminary DC solar cable 6mm2, red positive string runs; final size and route to be confirmed | 22 | m |
| OS-PNT-H1Z2Z2-K-06-BLK | Preliminary DC solar cable 6mm2, black negative string runs; final size and route to be confirmed | 22 | m |
| PV connectors | |||
| OS-PNT-PV004 | MC4-compatible connector pair, 1000V DC rating; layout quantity to be confirmed | 2 | pairs |
| DC protection & combiner | |||
| DIRECT-INVERTER | Combiner not included in this preliminary BOM for 1 string(s); confirm inverter MPPT/input count and local DC protection requirements | — | - |
| OS-ETK-EKD16-DB32 | Lockable DC isolator switch, 1000V DC; preliminary grouping to be confirmed | 1 | pcs |
| OS-ETK-EKU5-T2-20PV | DC SPD Type 2, 1000V DC; preliminary grouping to be confirmed | 1 | pcs |
| AC protection | |||
| OS-ETK-EKM1-32AC | AC MCB 32A, 1-pole inverter output breaker; rating to be confirmed | 1 | pcs |
| OS-ETK-EKL12-63X | RCBO 32A, 1P+N Type A 30mA leakage protection to be confirmed by local code | 1 | pcs |
| OS-ETK-EKU5-T2-20 | AC SPD Type 2, single-phase; confirm grid code requirements | 1 | pcs |
| OS-AC-CABLE-6SQ | Preliminary AC cable 6mm2, 3-core inverter-to-switchboard run; voltage drop to be confirmed | 8 | m |
| Grounding system | |||
| OS-PNT-GND-BVR6 | BVR grounding cable 6mm2 yellow-green | 24 | m |
| OS-GR-CLAMP | Grounding lug / earth bond clamp | 10 | pcs |
RFQ starting point
Use the output to request supplier pricing, not as a final engineering drawing.
Product matching
OmniSol can map each line to available product families, variants and certificates.
Export handling
The BOM can be packed as a mixed shipment with labels, cartons, pallets and documents.
How This Calculator Works
Wind pressure
Dynamic wind pressure q = 0.5 × ρ × V² (ρ = 1.2 kg/m³). Design wind speed V is derived from the selected standard and site inputs — AS/NZS 1170.2 regional speed × terrain multiplier, ASCE 7-22 Vult × exposure factor, or EN 1991-1-4 vb × roughness coefficient. A preliminary roof factor (1.2–1.6×) is applied based on roof type and panel tilt to give the uplift design pressure.
Snow load & governing case
Ground snow load s_k (kN/m²) is adjusted by the pitch-dependent shape coefficient μ₁: 0.8 for tilts ≤ 30°, linearly reducing to 0 at 60° (EN 1991-1-3 method). Wind spacing is back-calculated from clamp uplift capacity; snow spacing from rail bending capacity (M = wL²/8). The smaller of the two is the governing spacing shown in the output.
BOM generation
Rail count, splice, clamp, and interface quantities are calculated from array dimensions, orientation, and governing spacing. DC cable size is selected by string current; AC cable size by inverter output current. String count determines whether a combiner box is needed. All BOM lines link to OmniSol product pages and can be copied or sent via WhatsApp for quotation.
All spacing values are rounded to the nearest 50 mm and capped at 1,600 mm for preliminary use. This tool is designed for RFQ preparation and sourcing — it does not replace a project-specific structural engineering report, inverter MPPT check, or cable voltage drop calculation. Final certified designs must be prepared by a licensed local engineer.
Calculator FAQ
- What is the difference between wind spacing and snow spacing?
- Wind spacing is the maximum clamp support distance calculated from wind uplift pressure on the panel surface. Snow spacing is calculated from the bending load of accumulated snow on the rail. The calculator takes the smaller of the two as the governing spacing — the one labelled "Governs" in the output.
- What does "governed by snow" mean in the output?
- It means the snow load on the array is more demanding than the wind uplift load and requires tighter support spacing. This typically occurs at high ground snow loads (above 1.5 kN/m²) combined with low roof pitch angles that allow snow to accumulate rather than slide off.
- How do I find my wind region in Australia?
- AS/NZS 1170.2 divides Australia into four regions: A (Sydney / Melbourne — 45 m/s), B (QLD coast / Brisbane — 57 m/s), C (Cairns / Darwin — 66 m/s) and D (severe cyclone sites — 80 m/s). Check the wind region map in AS/NZS 1170.2 or consult a local engineer if your site is near a regional boundary.Deep dive: AS/NZS 1170.2 wind load guide →
- How do I find the correct wind speed for a US project under ASCE 7-22?
- ASCE 7-22 provides Vult maps by ZIP code and Risk Category. Use the ASCE 7 Hazard Tool or ATC Hazards by Location to find the site-specific value, then enter it in the Manual Vult field. The calculator's regional presets are starting-point estimates only.ASCE 7 Hazard Tool (external)
- Can I use this calculator for commercial or utility-scale projects?
- The output is a preliminary BOM estimate suitable for RFQ preparation at any scale. Commercial and utility projects require a project-specific structural engineering report, certified load calculations and local authority approval. Use the output as a sourcing baseline, not a stamped engineering document.
- Why does the BOM include cables and protection items, not just mounting hardware?
- The calculator generates a full preliminary BOS take-off so installers and distributors can send a single consolidated RFQ covering mounting, PV cables, connectors, combiner boxes, DC protection, AC protection and grounding. Sourcing all BOS in one shipment reduces freight cost, customs entries and coordination effort.
- How accurate is the rail support spacing output?
- The spacing is a preliminary estimate rounded to the nearest 50 mm and capped at 1600 mm. Actual certified spacing must be confirmed by the mounting system manufacturer's span table or by a licensed structural engineer using the exact rail and clamp product with site-specific load inputs.
- What EN 1991-1-4 terrain categories are available?
- Categories 0 (sea/coastal), I (open plain), II (open country — default for ground mounts), III (suburban — typical for residential rooftops) and IV (dense urban). Select the category that best describes the terrain roughness within 10 km upwind of the site.Deep dive: EN 1991-1-4 wind load basics →
- Is this calculator free to use?
- Yes — completely free, no login or registration required. The OmniSol Wind & Snow Load Calculator is provided as a free engineering tool for installers, distributors, and procurement teams worldwide. The BOM output links directly to OmniSol product pages, and you can send the full BOM to OmniSol via WhatsApp for a factory-direct quotation.
- What countries and standards does this calculator support?
- The calculator supports AS/NZS 1170.2 for Australia and New Zealand (wind regions A–D), ASCE 7-22 for the USA and Canada (exposure categories B/C/D with regional Vult presets), EN 1991-1-4 for Europe and global markets (13 country vb values including Germany, UK, France, Netherlands, Spain, Italy, Poland, Sweden, South Africa, UAE, Philippines, India, and Japan), and a manual wind speed input for any other standard or custom site value.
- What is a BOS BOM and why does this calculator generate one?
- BOS stands for Balance of System — all the components in a solar installation other than the PV modules themselves: mounting rails, clamps, roof interface hardware, DC cables, MC4 connectors, combiner boxes, DC isolators, surge protection devices, AC breakers, and grounding. A BOM (Bill of Materials) lists each component with quantity and unit. This calculator generates a preliminary BOS BOM automatically from your array inputs so you can send a single consolidated RFQ to one supplier — reducing freight costs, customs entries, and coordination effort compared to sourcing each component separately.
- What is the difference between AS/NZS 1170.2, ASCE 7-22, and EN 1991-1-4 for solar mounting?
- All three are national/regional structural wind load standards used to calculate design wind pressure on solar mounting systems. AS/NZS 1170.2 (Australia/NZ) uses four regional wind speed zones (A–D: 45–80 m/s) with terrain category multipliers, and a 500-year return period for permanent structures. ASCE 7-22 (USA/Canada) uses ZIP-code-specific Ultimate Design Wind Speed maps by Risk Category, with exposure categories B/C/D. EN 1991-1-4 (Europe and many global markets) uses a basic wind velocity vb from each country's National Annex with terrain roughness categories 0–IV. The physical calculation approach (q = 0.5 × ρ × V²) is the same in all three; they differ in how wind speed is mapped and what terrain/return period factors are applied.Full standards comparison guide → →
- How do I convert the BOM output into a purchase order?
- Use the "Copy BOM" button to copy the full BOM as tab-separated text, then paste it into an email or spreadsheet. Alternatively, use "Send BOM on WhatsApp" to send it directly to OmniSol's sales team. OmniSol will map each SKU to available product families, confirm technical variants (frame height, clamp type, cable cross-section), and return a factory-direct quotation with lead time and freight options. For large projects, request a formal RFQ via the Contact page to receive a project-specific quotation with engineering review.