To draw a solar single-line diagram, you lay out the system in order from the PV array to the grid, array, strings and MPPTs, inverter, DC and AC isolation, switchboard, metering and the grid connection, using AS/NZS 5033-aligned symbols. Below is the element-by-element method; in Solar Proof most of it is filled in from your design automatically.
What you need before you start
Have the system design to hand: module model and quantity, how the array is grouped into strings, the inverter model and its number of MPPTs, and any battery. The SLD documents these, so the diagram is only as accurate as the design behind it.
How do you draw a solar SLD, step by step?
Work left to right (or top to bottom), following the path of energy from the array to the grid:
- Place the PV array. Show the module type and quantity, and group modules into strings as designed.
- Add strings and MPPTs. Connect each string to the correct inverter input so the MPPT arrangement is clear.
- Add the inverter. Show its model and rating as the transition from DC to AC.
- Add DC isolation and protection. Place DC isolators and any string protection in the correct positions.
- Add AC isolation and the switchboard. Continue to the main switchboard with AC isolation shown.
- Add metering and the grid connection. Finish at the meter and the point of connection to the grid.
- Add batteries if present. Place storage and its isolation on the same one-line diagram.
- Label and export. Confirm labels and conductor detail, then export a print-ready A3 or A4 PDF.
How long should it take?
By hand or in generic CAD, a residential SLD is often 15 to 20 minutes once you are practised, longer if you are arranging symbols from scratch. In Solar Proof's SLD editor it is usually a few minutes, because steps one to three are already done, the array, strings, MPPTs and inverter come straight from your design, and you spend your time confirming the layout rather than building it.
Common mistakes to avoid
- Isolators in the wrong place, or missing, on the DC or AC side.
- String and MPPT arrangement that does not match the actual design.
- Generic symbols that are not aligned to AS/NZS 5033.
- An SLD that drifts from the install, redrawn from an old template and never updated.
Generating the SLD from the live design avoids the last two, because the diagram and the system are the same source.
The bottom line
Drawing a solar SLD is a matter of laying the system out in order from array to grid with the right symbols and isolation. Doing it once by hand is worth it to understand the parts; for everyday jobs, generating it from your design is far faster and stays consistent with the install. Try Solar Proof's SLD editor →
