Electric shower cable sizes

[crawfordkenny2000]

I am going to install a 9.5 KW shower or possibly a 10.5Kw shower, what size cable should I use. When I use your cable size guide it says 6 - 10mm. Does that mean I can use either?

 

[MANDATE]

It is dependent on the amperage the cable can take safely.
A 9.5 K/W needs approx 40 amps and a 10.5 K/W needs approx 44amps.
I think you will find 6mm cable is only suitable up to about 8.0 K/W and above that to be safe you should use 10mm.
Having said that! there is no doubt a safety factor applied, if a cable is rated at 35 amps it will probabley take 40 amps
I do however agree it is a grey area and the same question arises with cookers.
It will be interesting to see other replies

 

[breezer]

something else to be taken into cosideration is voltage drop, the longer the run the more voltage will be lost so to overcome this you use a bigger cable.

That said the predomant factor is how much current will be drawn. if your shower does draw 44 amps in acording to this (table 4.7) you can use 6mm cable, but it is always best to err on the side of caution and have the next size up which is 10mm, besides using 10mm has several advantages.

If you get a bigger shower you can keep the 10mm cable

you will not have to worry about voltage drop

go for the 10mm!