Cable for a more powerful shower. 6mm or 10mm

[bagpussuk]

Hello. I'm wanting to upgrade my 8.5kw shower to 10.5 or 10.8kw.

I think I have 6mm cable but not 100%. The picture of the white cable is what I have now, the picture with grey is what I checked out at the store.

Can anyone advise? My white cable is around 13mm in width. I don't have any photos of each end as not opened up either end. This is what is showing in the loft.

I was just initially wondering if I had big enough cable (I'm betting I don't).

Thanks.

 

[flameport]

Almost certainly 6mm for the existing cable.
'Upgrading' to a 10.5kW will make next to no difference.
Far better to ditch the electric shower and install a proper one.

 

[ban-all-sheds]

25% more flow at the same temperature, or a hotter shower at the same rate, or a bit of each is not "next to no difference".

Yes, a "proper" shower will always be better, but if that isn't an option then a 10.8 electric works pretty well. I can recommend the Redring Selectronic, as that has proper thermostatic control, not the next-to-useless "anti-scald" feature of most others.

Or if you don't mind the naff styling, they do a thermostatic mixer to go with their Powerstream range of instant heaters, and you can get one of those in a 12kW.

 

[endecotp]

I think I have 6mm cable but not 100%. The picture of the white cable is what I have now

You should be able to find some codes printed or embossed on the cable. In the photo we can see what I think is the manufacturer name; what else can you find?

 

[ban-all-sheds]

For some reason I missed this:

cable is around 13mm in width

Almost certainly 6mm². [wiki]electrics:cable_types:flatpvccables[/wiki]

Might be OK for a 10+kW shower, might not.

• http://electrical.theiet.org/wiring-matters/28/appendix4.cfm?type=pdf
  
  
• http://electrical.theiet.org/wiring-matters/40/appendix-4.cfm?type=pdf]
  
  
• http://www.batt.co.uk/upload/files/4d5.pdf
  
  The first two links are incomplete. You will need to refer to the latest edition of the Wiring Regulations to get the full info.

 

[Iggifer]

Also pretty sure it's at most 6mm², 10mm² is a monster.

Easiest way is to just check the cpc, see if it's one strand or multi