new shower installation

[fattony]

i can see this argument going on for a while, yes the purpose of a mcb is to protect cable, the point i was making was if the correction factors reduced the current carrying capacity to below 40A and the guy didn't want to rewire the supply he could use a 32A, yes this could cause nuisance tripping if the temperature was set to the highest.

Personally I would still use a 10mm, for peace of mind - you could argue the cable will cost more but i'll live with that.

 

[fattony]

i can see this argument going on for a while, yes the purpose of a mcb is to protect cable, the point i was making was if the correction factors reduced the current carrying capacity to below 40A and the guy didn't want to rewire the supply he could use a 32A, yes this could cause nuisance tripping if the temperature was set to the highest.

Personally I would still use a 10mm, for peace of mind - you could argue the cable will cost more but i'll live with that.

 

[Spark123]

But if he did stick to a 32A mcb then he should only ever install a 7.5kW (give or take a little) unit. If installing the cable new I'd say install 10mm as a minimum, possibly even 16mm depending on the situation as this removes some of the problems associated with upgrading the shower at a later date.