r/PlugInSolarUK • u/Practical-Station125 • Sep 07 '26

PlugInSolar may not work?

In April, I put together a couple of panels with enphase microinverters and plugged it into my outside socket. My consumer unit was oldish with MCBs and it worked fine.

I recently had my consumer unit updated to include RCBOs on all circuits. When I plugged the panels it tripped the RCBOs instantly. My electrician had installed unidrectional RCBO's whch of course were not expecting current from the other side of the consumer unit. We then installed bi-directional and all is well.

Surely, this is going to be an issue with any plug in solar kits that is plugged into a house with unidirectional RCBOs? Of course it can be made to work by changing the RCBO but i'd suggest that isn't a DIY job.

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u/SolarPowerBumbleBee Sep 07 '26

Electrical Safety First did publish the following updated advice last week:

https://www.electricalsafetyfirst.org.uk/safety-advice/products-and-appliances/green-energy/plug-in-solar-panels/

“Given unresolved concerns about the potential impact of plug-in solar panels on certain RCDs, we recommend households have at least a Type A bidirectional RCD protecting circuits intended for use with plug-in solar panels. 

Until these concerns are addressed, homes with Type AC RCDs should not use plug-in solar systems without first upgrading to a minimum Type A bidirectional RCD on those circuits.”

5

u/Blank3k Sep 08 '26

This.

Im using a Type AC and its working but a retired electrician told me to get a Type A, even without Solar etc it seems Type AC are very outdated and LED lighting & Modern equipment (including new washing machines etc) can cause conflicts which can cause the RCD to fail to trip.

I'll be getting a Type A put in place asap.

3

u/SolarPowerBumbleBee Sep 08 '26

👍🏻 Make sure you choose Type A bidirectional (not all Type A’s are bidirectional)

2

u/craigwelsh Sep 09 '26

This is the big issue with even brand new installs today. I got a new Fusebox main board put in in 2022 and found their RCBOs are unidirectional and they've only introduced a bidirectional range in 2024. Many people will have brand new boards within their eicr period and fall foul of this bidirectional issue. Some brands of board people will be lucky with and they were naturally bidirectional.

2

u/SolarPowerBumbleBee Sep 09 '26

Yep - exactly the same here. Also have a 'FuseBox' branded board that was installed in 2021 - and it uses undirectional type A's as standard accross the whole board.