Cooker and shower on the same circuit

The regs do not exactly say 'never connect a shower and a cooker to the same circuit'

and

I am not aware of any regulation that says "you can not do that" But as has already been said it is a very odd way to proceed and poor practice.

and

A long time ago the regulations did have a stipulation to the effect that circuits rated above 15A could only serve a single 'point', but that was a very long time ago

and

As long as the OCPD is suitably rated to protect the cables, then I don't see any safety issue. If the shower and cooker overlap for a bit, the cable will get a bit warm. It's unlikely the cooker will be on full power for any long length of time - otherwise the kitchen would start getting unbearably hot. In unusual situations where there is a long overload, the OCPD will eventually trip. This is inconvenient but not dangerous.

good grief !

Oh come on, this is not standard practice for level 3 journeyman electricians doing work in domestic installations being used by non-competent persons is it?.

Please do not justify imaginative electrical solutions that are perfectly acceptable on an establishment under the direct control and supervison by a competent electrical engineer with basic standard domestic installations likely to generate ambiguity, confussion and eroneous solutions for others who will be obliged to provide the maintenance. 

The regs do not exactly say 'never connect a shower and a cooker to the same circuit'

and

I am not aware of any regulation that says "you can not do that" But as has already been said it is a very odd way to proceed and poor practice.

and

A long time ago the regulations did have a stipulation to the effect that circuits rated above 15A could only serve a single 'point', but that was a very long time ago

and

As long as the OCPD is suitably rated to protect the cables, then I don't see any safety issue. If the shower and cooker overlap for a bit, the cable will get a bit warm. It's unlikely the cooker will be on full power for any long length of time - otherwise the kitchen would start getting unbearably hot. In unusual situations where there is a long overload, the OCPD will eventually trip. This is inconvenient but not dangerous.

good grief !

Oh come on, this is not standard practice for level 3 journeyman electricians doing work in domestic installations being used by non-competent persons is it?.

Please do not justify imaginative electrical solutions that are perfectly acceptable on an establishment under the direct control and supervison by a competent electrical engineer with basic standard domestic installations likely to generate ambiguity, confussion and eroneous solutions for others who will be obliged to provide the maintenance. 

I'm afraid I agree with Wally above. It is perfectly true (unfortunately) that this may not be understood by many "electricians", but that is because they are not suitably qualified for the job. The only point could be that the "manufacturers instructions" state a final circuit CPD, but this can be installed at any convenient point at the connection to the circuit, making the large supply simply a sub-main. In fact it may be a very convenient way to prevent mahem trying to install a new circuit , when the arrangement will make installation easy. Cable "overload" is perfectly safely handled by the CPD in the CU, and load diversity takes care of the rest. Tripping is very unlikely and should it ever happen, so what? Just reset and stop showering. Neither appliance can take excessive current due to any conceivable fault, so why are we even having this discussion? "Standard Practice" is a poor excuse for failure to understand the most basic part of circuit design! Also this priority switch idea is daft too, exactly why?