pat wrote:
My original 8.5 kW nominal shower stopped working due to hard water. I
replaced it and upgraded to 9.5 kW nominal. That gave me a much better
shower. Now that one has stopped working for the same reason. I
installed a water softener but still need a new shower. I want to
replace the shower with another 9.5 kW nominal unit. The house is only
about 7 years old. The shower circuit has its own 40 A fuse on the
board.

My simple arithmetic tells me:
9500 W / 230 V = 41.3 A
9500 W / 240 V = 39.6 A

But some people say 40 amps means 8.5 kW.

1. Which voltage should I use in the calculation: 230 or 240 V?
2. Which voltage do UK shower specifications use when describing it as
9.5 kW?
3. Anything else I should consider?

Thanks in advance

Use a 45A fuse, although if the house is only 7 yrs old, you will need a
breaker (mcb)