Shower 32amp breaker

The degree of unpleasentness rather depends on the true consumption of the shower, vs the breaker rating, - 8.5kW at 230V (36 amps), or at 240V ( 35A) or indeed a shower that would have been 35A if the supply was 240V but in a rural location where the supply reaching the shower is more like 220, then 33A. . 

So is it safe ? The breaker may trip, if the user stays in the shower for a very long time, but I think for the cable size it feels nicer to have something giving closer protection than a 40 or 50 amp breaker. In a house with an 80 or 60A company fuse, it probably seems to be a better fit to the maximum demand, though really it makes no odds.  (and you will occasionally find the odd shower has been added in on Henley blocks without anything other than the company fuse for top cover, but that really is much worse than the undersized breaker.)

To the letter it is a regs fail as you are designing for a small overload in normal operation. In practice, it seems to work just fine. And a shower on 4mm cable would probably be OK too.

I suspect the folk who do it always used to fit a 30A fuse, and have not read the label on the box of the shower, or only had a 32A breaker in the kit of parts.

The degree of unpleasentness rather depends on the true consumption of the shower, vs the breaker rating, - 8.5kW at 230V (36 amps), or at 240V ( 35A) or indeed a shower that would have been 35A if the supply was 240V but in a rural location where the supply reaching the shower is more like 220, then 33A. . 

So is it safe ? The breaker may trip, if the user stays in the shower for a very long time, but I think for the cable size it feels nicer to have something giving closer protection than a 40 or 50 amp breaker. In a house with an 80 or 60A company fuse, it probably seems to be a better fit to the maximum demand, though really it makes no odds.  (and you will occasionally find the odd shower has been added in on Henley blocks without anything other than the company fuse for top cover, but that really is much worse than the undersized breaker.)

To the letter it is a regs fail as you are designing for a small overload in normal operation. In practice, it seems to work just fine. And a shower on 4mm cable would probably be OK too.

I suspect the folk who do it always used to fit a 30A fuse, and have not read the label on the box of the shower, or only had a 32A breaker in the kit of parts.