Electrical

Which size cable to run to a shepherd hut/tiny house

Anonymous user 3 March 2024 - 3.42 PM

I am building a shepherd hut with shower and kitchen about 46m away from my consumer unit in the house. I have 2 questions: I would like an on demand water heater for the shower and 1 tap in the kitchen. The water heater I am looking at is 10-12kW. The showers will be (hopefully) short and perhaps twice a day. My electrician suggested to avoid them and have an 80-90l unvented hot water tank with a 3kW immersion heater on a timer. However, I fear that when a shower is needed in the morning and late afternoon the timer is rather pointless and the heater probably will be on all the time in which case the energy consumption goes up (I find values of 2700 kWh for annual consumption on these things). Also, as the shepherd hut is a rather tiny house, space is a problem and the hotwater tank probably would have to be installed on the outside of the hut, probably resulting in more heat loss? My first question is which water heating system would be better in energy? Then the second question is which thickness of armoured cable should I run? The non-armoured part in the main house is about 15.5 m, then 31m armoured cable outside (dug into the ground) till the consumer board in the hut. I will earth it near the hut with a spike, so I guess I can run a 2 core cable. For the hotwatertank system my electrician suggested a 16mm cable would be enough, but would this also be enough for the on-demand water heater? The other equipment in the hut would be a 2-ring induction cooker, a small fridge, a kitchen and bathroom fan, some lighting (probably LED), a computer and monitor, some charging points, a kettle, microwave/small oven, and then some 6-8 sockets. Any advice is very welcome.