I have a 7.5kw shower installed and I want to upgrade to a 9.5kw shower how can I tell if the existing cable can take the load of the new shower is it the measurement of the outer casing of the cable or the diameter of the inner cable also the distance from the consumer unit to the shower is about 10mtrs the load coming into the consumer unit is 80amps the consumer unit has apart from the breaker for the shower 2x5amp-2x30a-1x15a when the 7.5kw shower was installed I have since noticed that in the loft the cable comes from the consumer unit to a 30 amp round plastic junction box and then onto the shower as if they ran short of cable and decided to join it is this safe

Some capital letters and punctuation would make your post easier to read.

Need to know the mm-2 square of the inner cores to know the size wire you have. This should be printed on the outer sheathing of the cable.

Is the voltage 230 or 240 volts?