The company I work for has just had a 5 kw electric shower installed into my flat. It has been installed as a spur to a 2.5 mm ring main. The ring main is not earthed. (Not unusual here in Jordan) The appliance is (I beleive) double insulated. I run several other appliances, including two electric blankets on the same ring. I have a feeling that this may be overloading the circuit (220V mains). If my calculations are correct, the shower should be installed as a direct line to the distribution board using 4 mm cable. The length of the run would be about 15-20 metres. Can you advise?