electric storage heaters

[rogerorkney]

The immerison heater will only work at night. many have a top-up heater in the top of the hot water cylinder, which is connected to the normal supply. dont know about the heater you describe though.

so this means the main immersion (3kW) will be powered from the cheap meter on a 16amp dp mcb

and the top immersion (3kW) is to be powered from the main cu with a 16amp dp mcb?

 

[crystal ball]

With the dual immersion heater set up on E7, all you need is a E7 Horstman timer which will switch in the main immersion overnight and allow you to use the small boost immersion during the day, if you only have one immersion heater the timer can be linked through so you can use it as off peak or on peak, if that makes sense, ie you only need one supply to the immersion heaters.