Prysmian 6242Y Grey 6mm² Twin & Earth Cable 10m Coil (29733)

No, this is for cookers, showers and car chargers etc. You don't need a 6mm core cable if you're terminating with a 13amp plug. You shouldn't really be putting a plug on any kind of solid core cable.

You need to refer to the manufacturer of the hob. It may be given in the handbook. For your information a 6KW load will pull 26 amps and you can find the data sheet for the products on the Prysmian web site (search for whyprysmian). However you still need to refer to the manufacturer for this application.

Generally speaking for 32Amp ring main 2.5sqmm 6242Y is used & the same size is recommended throughout the ring. Standard 13Amp sockets will only take up to 10sqmm total into each terminal so you may have trouble terminating depending on how many cables are going into the socket. Regards Peter Fox

Your 8.5kw shower will pull 37 amps. So this cable will be adequate only if it is clipped or in plaster. For any other of the listed methods of installation as shown in Table 4D5 of the regs it will be insufficient. i.e. you may need a 10mm².