I'm currently doing some work on our holiday chalet near Minehead and noticed that the Triton water heater is connected using 1.5mm T&E cable. It's a 3Kw unit which, if my maths is correct (assuming 230v) will draw 13A. I've checked the Triton web site and they say a minimum of 1.5. The cable runs in the wall (wood outer, Celotex insulation, MDF). Isn't that running very close to the max for 1.5mm? What would you lot use? My thoughts would be to rewire with 2.5mm.