I get 39.93A for a 240v rated 10kW shower connected to a measured 230v supply.
10000 / 240 = 41.67amps (I=P/V)
240 / 41.67 = 5.76ohms (R=V/I)
230 / 5.76 = 39.93amps (I=V/R)
10000 / 240 = 41.67amps (I=P/V)
240 / 41.67 = 5.76ohms (R=V/I)
230 / 5.76 = 39.93amps (I=V/R)
