A practical, Australian guide to designing a solar PV system: assess the site, size the array, lay out panels, string the inverter within AS/NZS 5033 limits, and check production and compliance. Here's the workflow, and how to do it faster in Solar Proof.
What you'll need
- The customer's energy usage (a power bill, or interval/NEM12 data for accuracy).
- Roof details, orientation, tilt, available area and shading.
- CEC accreditation if you're claiming STCs on the install.
Step 1 — Assess the site
Confirm roof orientation, tilt and usable area, and note any shading from trees, chimneys or neighbouring buildings. Pull the customer's usage so you're designing to real demand, not a guess.
Step 2 — Size the system
Size the array to usage, budget and roof space, then choose an inverter to match. A bill tells you roughly how much energy to offset; interval data tells you when it's used, which matters for self-consumption and battery sizing.
Step 3 — Lay out the panels
Place panels on aerial imagery, grouping by orientation and keeping clear of shaded areas. Account for setbacks and access where required.
Step 4 — String and select the inverter
Assign panels to strings and MPPTs so every string stays inside the inverter's voltage window across temperature extremes, per AS/NZS 5033. Match string lengths on shared MPPTs. (See auto-stringing explained.)
Step 5 — Check production and compliance
Run a production simulation with shading factored in, then produce the single-line diagram and a compliant proposal with honest savings figures.
Australian-specific note: always design to the lowest expected site temperature for maximum-voltage checks, and confirm the inverter is on the CEC approved list. STC eligibility depends on a CEC-accredited install.
Keep exploring
Frequently asked questions
How do you size a solar PV system?
Size the array to annual usage, roof area and budget, then match an inverter. Interval (NEM12) data or a power bill gives the usage profile needed to size accurately.
What standards apply in Australia?
AS/NZS 5033 for array installation, AS/NZS 4777 for grid-connect inverters, and CEC accreditation for installers claiming STCs.
Do I need design software?
Not strictly, but it speeds up layout, shading, string sizing and compliance docs and reduces errors. Solar Proof does these in the browser and carries the design through to a proposal and SLD.
