Shower cable 6mm or 10mm

normally a 10mm twin and earth would/could be installed although 6mm twin & earth installed using reference method c has a current carrying capacity of 47amps which would be sufficient enough for most showers as calculations show below 10500watts divided by 230volts = 45.65amps 9500watts divided by 230volts = 41.30amps 8500watts divided by 230volts = 36.95amps 10.5kw shower is the highest that would probably be installed the 10mm twin & earth has a current carrying capacity of 65amps using reference method c which would still do the job but a bit overkill im sure your registered electrician has suficiently designed the circuit ****10mm is not the current industry standard Each circuit is individually designed for it's purpose , you have a 6mm cable installed using reference method C the cable will take 47amps there is no problem here you are free to fit any shower 8.5kw +

10mm cable should be used on showers of 8.5kw and above, so yes if your fitters are saying that the best showers are those with the highest rating (e.g.10.8Kw), then they are right in that the 6mm cable is inadequate. This issue is that unless you had bought the shower already or were clear with your electrician, then its not really his fault, as he would not know what type or rating of shower you were going to get? . A standard 7.5 to 8Kw shower is fine on 6mm cable. Ideally the pro's and cons of both cables and costs should have been discussed, but the risk is that if you fit an 8.5kw or higher powered shower on the installed 6mm cable, the cable may be overloaded and get damaged.

Hi there, You can use 6mm cable for up 9.2 kW. Only condition is if you have a 9.2 kW shower on a 6 mm cable it should not be more then 6 meter away from the consumer unit. But 7.5 kW is ok. If you have a shower more then 9.2 kW, 10mm cable must be used. I normally always use 10 mm cable if the shower is 7.5 kW or more. At least this way proper wiring is done and in future if the customer wants to change the shower to a more powerful one, cable is always there. Because it could be very costly to change the cable on a later stage. Specially after a whole new rewrite. When I do a job I always ask customer which shower they are going for. This way I calculated the job based on cable size. If your installer has done a 10 mm cable, it is good. You don't have to worry. I hope this helps, Regards,

Now cable size is dependent on the KW of the shower itself and the way the cable has been installed. I would normally use a 10mm cable for most shower installations as this allows for future upgrades and has the current carrying capacity for most/all installation methods.

10mm and Protected by an RCD will be sufficient for now and anything that you may require in the future.

If Gw electrics have installed a 6mm, and signed it of then y are you even questioning it? Are you gw electrics QS? Have you had another company around who carried out a full EICR ? They have signed a 5yr/10yr cert to say that the install complies .. well id hope they have .. so it's all good :)