Inverter Sizing Checker
Check array-to-inverter DC/AC ratio against CEC oversizing limits.
For reference only — always verify with the current CEC guidelines, your DNSP requirements, and consult an accredited solar installer for system design.
Solar Array
Panel Configuration
Inverter
About Solar Oversizing
In Australia, the Clean Energy Council (CEC) accreditation guidelines allow a solar array to be oversized up to 133% of the inverter AC rating (a DC/AC ratio of 1.33:1). This is the standard limit for systems to remain eligible for STCs (Small-scale Technology Certificates).
Why oversize? Solar panels rarely produce their rated output — shading, temperature, orientation, and soiling all reduce real-world yield. Oversizing ensures the inverter operates closer to capacity for longer, improving total energy harvest.
East-west split roofs are a common scenario where oversizing is particularly beneficial. With panels facing both east and west, only half the array is in full sun at any time, so the inverter almost never clips.
Max DC input is a separate electrical limit on the inverter. Even if the DC/AC ratio is within CEC limits, the total array power must not exceed the inverter's maximum DC input rating (found on the datasheet).
References: CEC Design and Install Guidelines, AS/NZS 5033, Clean Energy Council Accreditation Requirements.