I have just had a plumber install a new 10.5KW shower (upgraded from a 9.5KW). The plumber said he did not believe he can do the electrics as reading the install guide it says it recommends a 45A MCB and a 45A Switch. I currently have a 40A MCB and unsure what the switch rating is.
I phoned up 2 electricians both say they will do it and to ignore the guide and a 40A MCB will provide better protection than a 50A one (they don't do a 45A anymore apparently) and that I don't need to change anything, but neither would provide a certificate for the install so I am unsure who trust.
Should I just connect shower if this is all that is needed or should I demand the MCB/switch is changed and that I am provided with a certificate for the install.
So much stress just want it to be safe for use