My builders have installed two unvented hot water cylinders each with a 3kW immersion heater. Each heater has a normal 13A fused plug and they are both plugged into the same double socket. I wasn't sure whether the double socket is rated for 13A or whether 26A is acceptable. Can anyone advise? Also, I assume that even if this is on a dedicated circuit it needs a 30A fuse at the consumer unit... is this correct?