Why standards matter here
Solar performance is full of numbers that can be measured many different ways, and a number no one else can reproduce is worth little in a warranty claim, an audit, or a sale. Standards fix that: they make the measurement comparable and defensible. When two parties both work “to IEC 61724-1”, they mean the same thing by “performance” — which is exactly what makes a figure hold up under scrutiny.
IEC 61724-1 — the monitoring standard
IEC 61724-1 governs how a photovoltaic system’s performance is monitored: how to measure irradiance and output and derive performance metrics from them. Its most useful idea for owners is the split between performance and availability — separating “is the system online?” from “is it producing what it should when it is on?” Those are different questions, and a single headline number hides one of them. This is the standard behind a fair expected-vs-actual comparison.
IEC 62446-1 — commissioning & inspection
IEC 62446-1 governs the other half: the tests, documentation and inspection a grid-connected system needs at commissioning — and for periodic re-inspection afterwards. It is the template for what should be verified and handed over when a system goes live, and the checklist a system is measured against later. Where 61724-1 asks “is it performing?”, 62446-1 asks “was it built correctly, and is it still correct and safe?”
| IEC 61724-1 | IEC 62446-1 | |
|---|---|---|
| Governs | How performance is monitored | How systems are commissioned, documented & inspected |
| Answers | Is it producing what it should? | Was it built right, and is it still correct and safe? |
| Key idea | Performance vs availability; performance ratio | Commissioning tests, documentation, re-inspection |
| When it applies | Ongoing operation | At handover and periodic inspection |
“Aligned to” vs “certified” — the honest distinction
It matters how this is worded. We say our inspection is “aligned to” IEC 61724-1 — meaning we follow the standard’s methods and structure. That is deliberately not the same as being “certified” or “compliant”, which are formal claims requiring accredited third-party assessment. Overstating this is a credibility trap the moment someone checks, so the honest word is “aligned”.
How SPC uses them
Solar Performance Cloud grades string health and availability following IEC 61724-1’s performance-and-availability approach, and its inspection references IEC 62446-1 practice. The point is not the badge — it is that the numbers are comparable to a recognised method and the findings are defensible, rather than a bespoke score only we understand.
