If you mean the reset button under the immersion element cap keeps popping, then it is overheating.
Each heating element has a thermostat under its cap (turn off all power before removing the cap, or get a plumber or electrician to do it. The thermostat should be set at about 50-60C.
If the bottom one is too high it will trip first the upper one, then itself. Sometimes thermostats fail, and they can be replaced fairly easily. You do not have to drain the water to change the thermostat, because it is in a sealed tube.
If the element was incorrectly wired, it might be permanently on, bypassing the thermostat.
If you can safely do it, turn off the power, remove the cap, and photograph the thermostat and connections inside. It is dangerous to do this if the electricity is on.
It is I think more likely to be the bottom one at fault.
HOWEVER
if you mean that the tripswitch in the consumer unit ("fusebox") is tripping, then it is a different fault. In this case, photograph the thing that is tripping, and tell me all the numbers and letters printed on it. All of them.