Electric shower cable question

[broadbandylegs]

I'm going to upgrade an 8.5kw shower to 9.8kw Mira Azora. The photo shows the supply to the existing shower. I'm not sure if the cable needs to be replaced for the new shower. There are no markings on the cable apart from each wire labelled 'ONE 1' 'TWO 2' or 'THREE 3'. The cores are multi strand.
Can anyone identify the black supply cable for me to see if I need to upgrade it?
Cheers

 

[ericmark]

So 37 amps to 42.5 amps, using installation method 100 both would need 10 mm² rated at 45 amp. But that is for twin and earth, which is clearly not what you have, so it may be rated 60ºC, 70ºC or 90ºC, and we don't know how installed, we have a book full of methods some given here.

So how installed and type is important, so looking at table 4D5 we would have.

In theory, the cable is protected not the appliance, so if the protection device is not changed, then any overload would only trip the MCB/RCBO, but one can't be sure it was done correct to start with. I would normally test a cable size by trying crimps on the cable and see what size fits.

 

[Jurassicspark]

What is the MCB rating for the shower?

 

[broadbandylegs]

Thanks for that Ericmark

I'm redoing the shower room and have an electrician booked for next month to replace the old consumer unit - I was wondering whether I could box this part of the enclosure off before he appears, but I think I'll leave it open for access so he can advise. I live in the Highlands, so it's not that easy getting hold of trades...

Jurassicspark - it's a 40A circuit breaker - I appreciate it will be upgraded to latest regs