9.5 kw shower on 6mm ?

[jonthesparks]

just been to a job , saw that the shower 9.5 kw is on 6mm t&e the cable goes in the wall and under floor boards ,No insulation, to the board (A cable run of no more than 10 m) . I said downgrade the shower to 8.5 max. Is it really necessary ? never quite sure , its borderline to me .

 

[Guest123]

What is the rating of the MCB protecting the circuit??

 

[jonthesparks]

its
40 Amp

 

[jdd]

I don't think so, ref method C can take 46 amp.

 

[Guest55]

Not necessary to change shower , just make sure mcb is no more than 40A.
If it trips , it trips , no harm done

 

[Richard Burns]

Should just about be OK so long as there is no insulation about but really CCC is about 38A and you are running 41A, clamp the circuit and see what it is pulling. Doesn't comply at the moment but no need to change if it is working without damage, they are only on for a short time (tin hat).

 

[jdd]

Obviously breaker size should be 45A.

 

[Guest55]

Agree with richard , showers rarely used longer than 5-10 mins , too short a time for cable to heat up.

 

[robd]

Should be fine with a 40a in real life, be suprised if it trips, cable size just ok I'd say.

 

[Edd]

(A cable run of no more than 10 m) .

sounds a short run, why not price to upgrade to 10mm.. nice job, earn some money.

 

[sedgy34]

just been to a job , saw that the shower 9.5 kw is on 6mm t&e the cable goes in the wall and under floor boards ,No insulation, to the board (A cable run of no more than 10 m) . I said downgrade the shower to 8.5 max. Is it really necessary ? never quite sure , its borderline to me .

same here border line for me too i cant be arsed calculating it as others would slate it too

 

[sedgy34]

Not necessary to change shower , just make sure mcb is no more than 40A.
If it trips , it trips , no harm done

only customer got no shower

 

[Guest55]

Until he resets the mcb.
strewth.

 

[Farmelectrics]

I'd recommend upgrade to 10mm am I right in saying the breaker will take up to one and half times it's load which would pose a problem with the 6mm

 

[robd]

But 6 mm T&E can according to bgb can take 39a (I think without looking) and realistically the shower wont be pulling that (you could clamp it to see) therefor saying you should change the 6mm to 10mm is unneccessary (in my opinion). Doesn't matter that the MCB will take more than what it's rated at when the 9.5 kw shower wont be pulling more than the 40A

 

[sedgy34]

Until he resets the mcb.
strewth.

in his towel

 

[Guest55]

Agree with robd , as a fixed load , 9.5kw @ 230v pulls 41.3A
i wouldnt replace cable for an extra 1A for a few mins.

 

[Guest55]

in his towel

And that is an emergency that folk cant cope with ?

 

[SPARTYKUS]

....and if the owner accidentally leaves it on......... all day ......

Seen it!

Personally don't know enough detail about how (and if ) a shower left on "full" cycles (or not). Is it like a kettle, full tilt for the duration? I suspect not.

Dunno.

If in doubt change.

My gut tells me it might get warm but would be ok as long as PD matches CCC of cable.

 

[telectrix]

if it ain't broke, don't fix it. perfectly OK with a ccc of 47A on a 40A MCB.

 

[jdd]

Surely the only 'proper' way of doing it is 6mm cable, 45A breaker, Ref method C throughout.

That way Ib is less than In.

?

 

[Guitarist]

if it ain't broke, don't fix it. perfectly OK with a ccc of 47A on a 40A MCB.

47A is the absolute max under continuous clipped direct conditions with no VD. I personally wouldn't put 6mm on a 40A MCB, nor run a 9.5KW load on it, but that's just my opinion.

As far as not being in the shower for more than 5 or 10 mins goes.... tell my daughter that.

 

[markthespark]

Ive seen a 9kw shower ran on a 32 amp MCB

 

[Guest55]

Surely the only 'proper' way of doing it is 6mm cable, 45A breaker, Ref method C throughout.

That way Ib is less than In.

?

Yes , but many CU brands dont have 45A mcbs , next one up is 50 which will need 10mm cable.

 

[SPARTYKUS]

or make sure it hangs in free air betwixt CU and shower.

CCC is 51A then.

sorry just injecting some levity.

 

[telectrix]

47A is the absolute max under continuous clipped direct conditions with no VD. I personally wouldn't put 6mm on a 40A MCB, nor run a 9.5KW load on it, but that's just my opinion.

As far as not being in the shower for more than 5 or 10 mins goes.... tell my daughter that.

can you get a 45A, 5 minute time switch?

 

[Guest55]

Ive seen a 9kw shower ran on a 32 amp MCB

And there you go lol.
Did anyone die , get electrocuted or house burn down firewalshy ?

 

[Guitarist]

I'm not too fussed, that's why I installed a 7.5 KW shower

 

[markthespark]

lol nope but i did she a shower not sure what the kw rating was ran off a 30 Amp BS3036 fuse in 1.5mm 3 core!!!

At first glance i thought it was 4mm, looked in the loft and it was all melted under the insulation.

Still worked though i found it as i was installing a loft light.

 

[telectrix]

lol nope but i did she a shower not sure what the kw rating was ran off a 30 Amp BS3036 fuse in 1.5mm 3 core!!!

At first glance i thought it was 4mm, looked in the loft and it was all melted under the insulation.

Still worked though i found it as i was installing a loft light.

well, if you insist on using your 6mm for the loft light, you'll have to use 1.5mm for the shower as you'll have no 6mm left.