I had intended to install an 8.5kW electric shower. So RCBO for the shower is 40A, B curve and the cable is 10mm.sq.
The chap installing the central heating reckons that a 9.5kW shower would be better ...
At 230V, the 9.5kW shower would be c.42A, so over the 40A RCBO rating, but the I/In for that would only be 1.03.
From the RCBO curve (which is not super-detailed) it looks as if only a really long shower would trip the RCBO thermally!
The shower instructions specify 40A or 45A MCB, so don’t really help!
Presuming that the cable rating is okay as installed (mostly clipped), I reckon that the 9.5kW shower would be fine - am I missing anything?
