10mm shower cable

[D4N1EL]

i have recently installed a 10mm shower cable.

I was told by a salesman in a bathroom centre I can only run a 9.5kw or 10.5kw shower from a 10mm cable.

Is this true?

I have only installed the cable. When I'm ready, I will be getting an electrician in to connect it all up and install the correct fuse/switch in my fuse board.

Thanks for any advice.

 

[flameport]

I can only run a 9.5kw or 10.5kw shower from a 10mm cable.

10mm is often used for showers of that rating, although other sizes could be used depending on how and where the cable is installed.

 

[EFLImpudence]

Yes.

Unless the cable runs through (surrounded by) or is covered by >100mm. of thermal insulation.

The electrician should want to see the installation method before connecting.

 

[JohnW2]

Yes. Unless the cable runs through (surrounded by) or is covered by >100mm. of thermal insulation. The electrician should want to see the installation method before connecting.

Do/did you ever see (or install) 16mm² cables in shower circuits?

Kind Regards, John

 

[D4N1EL]

Hi,

The cable currently runs from my fuse board (not connected) along the top of my kitchen wall in some white trunking, up through the ceiling/bathroom floor into the loft to the area the new switch will be, then another wire from where the switch will be over the ceiling and down the wall to where the shower will be. The cables are 12 meters and 3 meters long.

None of them or under insulation yet and as there is plenty of slack, them don't need to be, I can slide the insulation under the wires.

Can I use a 8.5kw shower?

I have upgraded the cable from 6mm because I was told I can't use a shower more then 8kw on a 6mm cable.

Thanks

 

[D4N1EL]

In time the kitchen ceiling will be replaced and the cable will go in the ceiling.

Thanks

 

[JohnW2]

Can I use a 8.5kw shower? .... I have upgraded the cable from 6mm because I was told I can't use a shower more then 8kw on a 6mm cable.

Assuming that the cable in the roof is not covered in a lot of thermal insulation, then, given that some of your cable is in trunking, 6mm² cable (without any thermal insulation etc.) ought to be good for a shower up to about 9.1kW (at 240V). If the 6mm² cable were buried in a wall (or, as you suggest, moved to above the ceiling), rather than in trunking, it could support a shower up to about 11.2kW (at 240V).

Kind Regards, John

 

[D4N1EL]

Can I use a 8.5kw shower on a 10mm cable with out burning the shower out?

Thanks

 

[EFLImpudence]

Do/did you ever see (or install) 16mm² cables in shower circuits?

No -

but rather than have to derate a cable because it in a particular installation method, I would regard the ratings tables as an indication not to use that installation method.

Sometimes it may be unavoidable, I suppose.

 

[EFLImpudence]

Can I use a 8.5kw shower on a 10mm cable with out burning the shower out?

Yes.

It does not affect the shower at all; it is to prevent the cable overheating.

 

[JohnW2]

No - ....

That's what I rather expected.

... but rather than have to derate a cable because it in a particular installation method, I would regard the ratings tables as an indication not to use that installation method. Sometimes it may be unavoidable, I suppose.

Yes, all true.

Kind Regards, John

 

[sparkwright]

i have recently installed a 10mm shower cable.

I was told by a salesman in a bathroom centre I can only run a 9.5kw or 10.5kw shower from a 10mm cable.

Is this true?

I have only installed the cable. When I'm ready, I will be getting an electrician in to connect it all up and install the correct fuse/switch in my fuse board.

Thanks for any advice.

To clarify, as there seems to be some confusion later on, when the salesman said you could only run a 9.5kW or 10.5 kW shower from a 10mm cable he also meant showers below that rating (eg 8.5kW) are also ok on a 10mm cable.

To clarify further, a 10mm cable is the CSA of the live and neutral conductor of the cable.

 

[EFLImpudence]

I'm not sure that clarifies what the salesman meant.

You could run a 15kW shower on a 10mm² cable (method C).

You can run upto 11kW showers on a 6mm² cable (method C).

10mm² is often used as a submain supply for a whole flat.

 

[JohnW2]

You could run a 15kW shower on a 10mm² cable (method C).
You can run upto 11kW showers on a 6mm² cable (method C).

Indeed. However, as I said earlier, in the context of the OP's situation, I think we are talking Method B - hence the figures I posted.

Kind Regards, John

 

[EFLImpudence]

Yes, indeed, but I would not think the salesman was aware of that, was he?