If you have a Hot Water vessel, like this
or something similiar
and your not getting any hot water or the electric trips out.TtheN you need a new immersion heater.
It's likely the immersion heater has corroded like this:
This is a Stand Immersion heater for an open vented Hot water vessel. Whatr ever type of hot water vessel you have the syptoms are often common. Have a look at our services for more info.