max shower rating?

[topbanana]

hello all,have a recently fitted consumer unit (jan'03) by the local electricity board.
they put in 2 seperate 6mm cables to feed 2 separate showers-1 in the attic ext., 1 in the first floor bathroom.
both are served by 32amp mcb's.
the attic has a broken 7kw triton shower which needs replacing.
the bathroom has a 9.6kw shower.
the cable for the shower was installed at the time of the cu replacement, through the wall cavity for 4m, over insulation for 2m, then through the sloping attic ceiling (solid insulation) for 3m.
i need to replace the attic shower.
what would be the max kw shower i can install.
i wouldn't want to replace the 6mm cable with 10mm( wish they'd put it in, in the first place) if possible, but could replace mcb.
my main thought is too the capability of the cable.

 

[camieabz]

Don't know if this will help.

Linky

Based on the numbers 7Kw may be ok, but I'd get the cable length and insulation factors worked in. 10mm cable would have been better, like you said.