One issue surrounds residual current devices (RCDs), the safety devices found in fuse boxes that sense when current is leaking to ground – a sign of electrocution or a short circuit – and almost instantaneously cut power. Most RCDs used in the UK aren’t suitable for current flowing in both directions and so could malfunction. In the US, the set-up is different but there are similar problems. One reason why Germany has managed to move so quickly [on plug-in solar panels] is that by coincidence it standardised bi-directional RCDs in the 1980s. 2026 April 1, Matthew Sparkes, “Plug-in solar is coming – how dangerous is it and is it worth it? Plug-in solar panels are a cheaper, simpler alternative to professionally installed panels. But can they really reduce energy bills and are they safe?”, in New Scientist, retrieved 16 Jun 2026: