1. Checklist
Commissioning is not just about "turning on the inverter and being done." It is, in fact, a consciously structured technical inspection process. The goal is not just to make the system work, but to ensure it operates safely and reliably in the long term.
Proper commissioning prevents hidden faults that would otherwise cause, months later:
- unwarranted RCD tripping,
- inverter failure,
- loss of production,
- or, in worse cases, overheating and fire risk.
First, mechanical checks, then the DC side, followed by the AC side, and finally grounding and interconnections. Never in reverse order.
Mechanical checks
The essence of mechanical inspection can be summarized in a simple question: does the system hold what it is supposed to hold – for 20-25 years?
panel → clamp → rail → hook → rafter → building structure.
If there's a fault anywhere in this chain, it will cause problems over time.
The most important checkpoints typically include:
- whether the panels are within the manufacturer's specified mounting zone,
- whether the clamps are tightened to the correct torque (neither loose nor overtightened),
- whether the rails run flat,
- whether roof penetrations are waterproof,
- whether cables rest on sharp edges or tiles.
A common mistake is to "get over" the mechanical part because it seems stable at first glance. However, visual stability does not equate to correct fastening.
DC side checks
The DC side is the most critical part of commissioning. High voltage and a constant energy source are present here, so the consequences of errors can be more severe.
The inverter is still disconnected at this point. First, each string must be handled separately. The most important steps are:
- polarity check,
- open-circuit voltage (Voc) measurement,
- comparison of the measured value with theoretical calculations.
