Hi, hope this post is OK, I’m new to the forum. I had a PV system and battery installed in early 2022. In the time since it has worked fine but my RCD has tripped very randomly, anything from a day or two to several months between tripping. I didn’t associate this with the PV system. I’ve managed the tripping without ever being able to work out the cause. After every trip the RCD resets without a problem, suggesting it’s not a permanent fault. I have 10 MCBs in the consumer unit, none of which trip individually. Recently the tripping has, on occasion, become much more frequent. Last night it was tripping every 2 or 3 minutes. Although there wasn’t a problem resetting it, it would trip again after a minute or two. I isolated the circuits using the MCBs one by one but each time it still tripped until I got to the MCB for the PV system. I’m not an electrician so don’t understand exactly what the MCB does, but I assume it isolates the PV system and inverter from the mains. The inverter still seems to have power, from the battery? Does anyone have any suggestions as to why the PV system may be causing the RCD to trip?
Hi yah, lots of people have had issues with RCD’s myself including. I asked my installer and he said he only uses RCBO’s now type A. It maybe worth looking at changing the RCD that looks after the PV and just change that one?
I would also do some research on the type of RCD’s you have?
Thanks for that, sounds good. I’ll contact my installer and ask some questions. I was thinking that maybe the PV system should be separate from the other circuits in the consumer unit but as said I’m no electrician.
MCBs are Miniature Circuit Breakers ,and deal with overload currents typically due some sort of short circuit leading to high current flow. This protects the cables etc and makes sure it all does not melt/catch fire.
RCDs are Residual Current Devices. The RCD works by constantly monitoring the electric current flowing through a circuit; if it detects an imbalance between the live and neutral currents—meaning electricity is flowing down an unintended path, such as through a person—it will instantly trigger a relay to trip and cut the power, preventing electric shock.
Others have reported that you can get RCD trips because of capacitance of the PV panels and the presence of water - rain.
I had MCB’s in my fusebox controlled with an RCD and would get occasional trips as well.
I have had the entire fusebox replaced and the MCB’s swapped for Crabtree Starbreaker Type A RCBO’s. Not had a single false trip since then
Thanks for the replies and information. I’m getting in touch with the installer to discuss implementing some of the proposed suggestions regarding replacement with RCBOs.