What fuse

Dear all

I need a little advice regarding what amp fuse I need for my water heater. The hager fuse, pictured below, which I would like to change to a digital timer fuse does not indicate what amp it is.. The water heater is a 100ltr thermor. Any help would be much appreciated.

Many thanks


the disjonctuer will say c10 or c16.

The tank probably uses 1800W roughly 8 amps so a 10 amp breaker should do it. The one you have is ok, you just need to put a clock in. the clock you usually power from a 2amp fuse and the existing breaker sends the power to the tank when the contact closes.

looks like the breaker says c20?

20 is a bit over necessary for the task. The circuit should only supply the water tank so normally 16 would be right. Remember that the circuit breaker is there to protect the wiring from overheating. The cable should be at least 1.5 sq. It may be 2.5. Better to use the automatic switch powered by the supply meter (if you have dual pricing) which will switch the heater on in the cheap periods (crease).