Hi, i'm training to be an electrician and was looking at a fault with my shower at home. There was no power to the unit and i found a melted phase wire in the pull switch. the shower is rated at 9.8kw@240v and 9.0kw@230v. The cable run is approx 10m and wired in 6mm twin and earth and protected by a 40amp type b 60898 mcb. Done some calcs and it seems that this would be okay for volt drop and current carrying capacity of the cable. Question is, am i right???? and would i work out the power using 230 nominal or approx 240 actual voltage???