I had a PV system installed by a local reputable manufacturer last autumn; since then, I've received conflicting advice regarding the consumer unit protection required. I'm hoping someone may be able to clarify the protection required by the regulations in place last October.

I have a Solis S6 3.6kW inverter connected to our consumer unit. Initially this was protected by a 16A type B RCBO (Hager ADA316G) running into a double pole isolator and surge protection. The sparky at the time warned us one of these would need to be replaced in future however this was all he had available on the day. He also said he had had no formal PV training. Oddly, the documentation provided to us stated that the “PV system is connected to a dedicated 16A type B MCB in the consumer unit”.

After this I sought some advice from a trusted sparky and was told that we should have had an MCB installed but that this was only “advice” and not regulation because the company is not going back to fix any of their previous installs. So, I had this corrected and the 16A RCBO replaced with a 16A Type B MCB. Work which of course they want to charge for (while also removing the RCBO which I had already bought as well).

My concern is the conflicting “advice” and the fact that the company is happy to fit both breakers and charge for both. Could someone please clarify what should have been installed as consumer unit protection according to the regulations?
 
If the cable between the supply and the inverter is regular household twin and earth, and buried less than 50mm below the surface, or on the surface, then a 30mA RCBO would be right... just for protecting the cable. Do you know what size the cable is?

A 16A is cutting it fine if the invertor is generating the full 3.6kW.... most i've seen are oversized at 32A, with a 4mm cable to invertor.
Just to say, i am not a PV installer, but do take note when i see PV in houses ive been in.
 
There is no requirement to install RCD protection to PV system AC cable unless it's required because of installation method as mentioned above, or manufacturer instruction insist on installing one.
Looking at MI your system should be protected by 20A OCPD
 

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What are the regulations for PV consumer unit protection?
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Solar PV Forum | Solar Panels Forum
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