Shower wire

[MMJ]

How can I calculate ? How do I know what size cable I need?

9.5 kW shower
40 C ambient temperature
T+E cable installed in loft space
25m length of run
type B breaker

In 9500\230 = 41.30A
In 42A

 

[Spoon]

Hi MMJ,
Have a look in your BS7671 book and that will give the cable calcs & derating factors for installation method needed.

 

[uksparks]

25m is a good old run

 

[telectrix]

9500/240 = 39.6A. use a real voltage, not some half baked euro nonsense.

 

[Spoon]

25m is a good old run

As the OP has stated "T+E cable installed in loft space"

I wonder how much of that run is in the insulation in the loft?

 

[telectrix]

if it's run properly, none. till the free insulation monkeys come in.

 

[Darkwood]

If running any cables through an empty un-insulated loft you need to assume insulation will be installed in the future, its one of those cable designs you need to account for other trades in design

 

[MMJ]

As the OP has stated "T+E cable installed in loft space"

I wonder how much of that run is in the insulation in the loft?

20m in loft.

 

[telectrix]

run the cable up and over where any insulation may be thrown in.

 

[Spoon]

20m in loft.

What installation method are you using?

 

[PEG]

"Any warming up,of the cable,running through loft insulation,will be counter-acted by the cooling effect of running up,the cavity..."

^^ I heard this off a time-served lad,who does all the install,for a large kitchen/bathroom retailer...:20:

 

[slingshot2000]

"Any warming up,of the cable,running through loft insulation,will be counter-acted by the cooling effect of running up,the cavity..."

^^ I heard this off a time-served lad,who does all the install,for a large kitchen/bathroom retailer...:20:

And how does he take into account that somewhere down the line someone may blow glued polystyrene insulation into the cavity containing said cables ?

 

[Dave OCD]

And how does he take into account that somewhere down the line someone may blow glued polystyrene insulation into the cavity containing said cables ?

I think you're missing the main point here.

 

[davesparks]

How can I calculate ? How do I know what size cable I need?

9.5 kW shower
40 C ambient temperature
T+E cable installed in loft space
25m length of run
type B breaker

In 9500\230 = 41.30A
In 42A

Two problems with your calculation, the 9500w rating will be at 240V not 230V and you have calculated Ib not In. In should be selected based on Ib

 

[MMJ]

Shower

Hi is anyone tell what cable can I use for 9.5 kW shower . Plz I think it's 10mm and 40A but I m not sure.



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