- May 7, 2008
- Reaction score
- Sunny Plymouth
the classic update by adding a single external RCD for the entire board - no longer acceptable due to 'nuisnace tripping' ie a single fault wipes out the entire house elecrical supply.The points made about PV not sharing a RCD caused me to checkout our PV, installed 10 years ago.
The Wylex plug-in-fuse CU is fed from an external 100A 30mA RCD.
The inverter AC output is fed to the CU via 2.5mm2 to a Wylex plug-in 30A MCB the installers added.
Shouldn't that be more like a 16A MCB, to protect the cable ?
There are suitable rotary breakers between the PV DC and the inverter, between the inverter and the FIT meter, and between the FIT meter and the 30A RCD in the CU.
Though there is one unplugged hole and no glands on some of the breaker cable entries.
If only I know then what I've learned from this forum.......
30A is too large for a 2.5mm cable, which is rated at 26Amps maximum. I would fit 20Amp so that it's not pushing the mcb to it's limits.
Holes in board / isolators contravene 'ingress protection' and allow finger insertion - rough work.
To be frank, if you have the old plug in MCBs it may well be worth considering a full EICR (inspection and test) and getting the board updated. The one good thing about single RCDs is that you almost certainly havn't got any major issues with cabling / appliances, or it would keep tripping out.