Good Morning All,
While I don't want to preach anarchy it is well within the capabilities of an averagely competent DIY person to install Solar PV however there are an array of what can only be called 'limiting' regulations making this quite difficult.
As a 'non-certified' installer your local DNO would probably want to come and inspect/ check your install. Up here SSE reserve the right to inspect the first three installations of a 'new' installer before accepting any further applications from said installer. When I asked about extending my 4kW system, I was told yes I could but if using a 'non-approved' i.e. myself that would charge me £585.
There is also a requirement about electrical installations and being done by 'approved' electricians in recent years.
Having said this there are plenty of sources of information on the interweb which will provide more than sufficient information. The most challenging part is the installation of the panels which is risky and with modern large panels quite challenging. Downstream of this the inclusion of the, two pole, DC isolator switch before the inverter, the inclusion of a, 2 pole, AC isolator after the inverter and the wiring in of a suitable MCB into the consumer unit is actually pretty straight forward to be honest.
The inverters won't connect if it sees any of a number of faults and equally the MCB/ RCD in the consumer unit will operate to 'protect' if necessary.
My only faux pas of recent was installing an SMA Energy Meter after the main Solar PV isolation switch to input into Sunny Portal but only using a 6A MCB to protect the Energy Meter. Given the whole Solar PV system is connected to a 32A MCB I don't know what I was thinking. After it had tripped 3 times as the sun climbed in the sky and the power out of the Solar PV system rose the penny dropped.
As I say incorporate the necessary protection devices and you are pretty well protected.
Regards
Richard