A solar system is not finished when the last panel is fixed. Before it is switched on and handed over, it is tested and set up. These checks are the difference between a system that appears to work and one that is known to be safe and correct.
Testing the strings
Each string of panels is tested before it is connected to the inverter. The open-circuit voltage (Voc) tells the installer that the right number of panels are connected correctly and that the string voltage is what the design says it should be. The short-circuit current (Isc) shows that the panels are delivering current as expected. A reading that is off points to a wiring or panel problem that is far easier to fix now than later.
Electrical safety tests
The DC and AC sides are also tested for safety: polarity, continuity of protective conductors, insulation resistance and the operation of protective devices. The testing of grid-connected PV systems is covered by a British and European standard, BS EN 62446-1, and the installation itself by the IET Wiring Regulations, BS 7671, which has a section on solar PV supply systems.
Setting up the inverter
Once the tests are passed, the system is switched on and the inverter is configured: the grid settings that apply, the battery settings if there is a battery, and the connection to the monitoring app or portal. This is also when the isolators are labelled and the shutdown procedure is confirmed, so that anyone who needs to switch the system off knows how.
Handover
At handover you should be shown how to read the monitoring, what normal output looks like, what the inverter’s lights or messages mean and how to isolate the system in an emergency. You should also receive the documentation for the system. If an export tariff or a scheme you want to use asks for specific paperwork, raise it when you ask for a quote so that it can be discussed in advance.
Planning something like this?
If you would like to know what testing and handover documentation to expect, ask when you request a quote. You can read more on the system testing & commissioning page.