Size of cable required

emaom · 6 Jul 2010

Hi

We are putting up an outside building to house a hot tub, the recomended cable for this by the manufacture is a 6mm2 armoured cable. What i was woundering is if I ran 10mm2 to a fuse box in the out building would this be ok the then split off for separate sockets and lighting on different circuits.

The problem is we are just starting to dig and I thought to save the electrican pulling a cable through the pipe we are laying if i ran it in advance as i run the pipe it would save time or are the chances we will need something totaly different.

Hopefully the attached drawing will give you an idea of the plan. Is this something to get an electrican in at this stage before pipe are placed ?

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ban-all-sheds · 6 Jul 2010

You really really should get the electrician involved ASAP, because the type of duct used, and where it runs, how deep etc, are all aspects of design and construction which she will be signing certificates to say she did.

So she has to be the one to tell you where to run the ducting, what type and how deep etc. She won't mind in the least allowing you to get on and do the donkeywork, but she, and hence you, could possibly mind a great deal if you present her with a fait accompli which is no good.

Chri5 · 6 Jul 2010

Depth of dig needs to be 600mm from top of cable to ground / surface level.

Would suggest you provide a duct and draw rope for future works.

Are you intending to go via dig and then round the outside wall line back to the CU or a.n.other root ?

The manufactures 6mm cable may be over or under specified and will not take in to account the distance between CU and spa (how could they know the distance ?).

You need to know the load of the spa on full tilt to confirm the size of the cable, if you intend to split the cable as a feeder to a sub CU with spa, lights and sockets you need to calculate the full sub board load to then decide the cable size.

I'd 'imagine' that the spa will be about 30 amp, the lights a nominal 1 amp (so under 230w) and as for the sockets you could provide a mcb at the sub board to limit load to say 10 amp.

So its going to be 40 amp at main CU, 10mm swa to sub board with rcd.

On the rcd you have 30 amp mcb for spa, 10 amp for sockets and 6 amp for lights.

Since you intend to use a spark (who will cert the job) then get them in to design, you lump in the swa to his design, he comes back does local drops for sub board circuits and commissions the whole thing.

Chri5 · 6 Jul 2010

ban-all-sheds said:
design and construction which she will be signing certificates to say she did.

So she has to be the one to tell you where to run the ducting, what type and how deep etc. She won't mind in the least.

Have you gone all feminist ? Why the use of female over male ?

emaom · 6 Jul 2010

Thx will get in contact with an electrician in the area first sounds like it will save any problems.

ban-all-sheds · 6 Jul 2010

Chri5 said:
Have you gone all feminist ? Why the use of female over male ?

If I'd written he and him instead of she and her, would you be asking "Why the use of male over female?"?

What does thinking that someone has to be a feminist if they recognise that there are female electricians say about you?

Chri5 · 6 Jul 2010

Nothing was so ever.

Mum was an ardent trade unionist, a 60's, 70's and 80's feminist in the days when woman folk were laughed at for attempting so called 'male' job roles. She was a senior principal in the employment commission and got a CBE for positive working and changing employers attitudes to female workers- so don't go giving it any 'attitude' sir.

I asked out of curiosity, no more no less. It is normal for men, posting on the subject matter mentioned to deploy a he over a she. Please do not insult me simply because I asked a straight forward question.

Banter with you is extremely hard, try lightening off a bit and stop working to the paranoid assumption that any question asked of you must be a dig or an insult.

ColJack · 6 Jul 2010

BAS does that on occasion to show he's not a sexist pig..

do we count a hot tub as a "location containing a bath or shower" or do we count it as a "swimming pool and other basins"?

the answer defines if and where sockets outlets are allowed..
if it's a bath then sockets must be 3m from the edge of it minimum, and if it's a swimming pool or other basin then it's 2m minimum.

either way the socket should be RCD protected, as should everything in there really..

Risteard · 6 Jul 2010

Man as in mankind refers to either gender. As such he/his could legitimately be used but she/her cannot unless it is a female doing the work.

ColJack · 6 Jul 2010

I try to be gender neutral referring to "the electrician" and then "they" rather than"he" or "she" and "their" rather than "his" or "her".

of course I'm not always successful

disinfo · 6 Jul 2010

I reckon it was the subconscious.

Hot tub installation = female electrician

SteNova · 6 Jul 2010

disinfo said:
I reckon it was the subconscious.

Hot tub installation = female electrician

would be rude not to let the spark have the first go in the 'tub

ban-all-sheds · 6 Jul 2010

Chri5 said:
don't go giving it any 'attitude' sir.

I'm not - I just wrote something perfectly valid, but did not assume that the electrician would be a man, and you saw fit to remark on it.

I asked out of curiosity, no more no less. It is normal for men, posting on the subject matter mentioned to deploy a he over a she.

Maybe that normality should be challenged.

Please do not insult me simply because I asked a straight forward question.

I didn't insult you.

But I do think you should wonder why it even occurred to you to remark on what I wrote.

Banter with you is extremely hard, try lightening off a bit and stop working to the paranoid assumption that any question asked of you must be a dig or an insult.

I didn't think that at all. But I'm amazed that you thought it so abnormal to postulate a female electrician that you were moved to comment on it, and to speculate on why I wrote what I did.

Seriously - whatever your thought processes were, examine them, and challenge yourself - try to examine why when electricians can be male or female (and probably other gender types too) you would never be moved to question an assumption of a male one but you were by a female one.

Taylortwocities · 6 Jul 2010

emaom said:
Thx will get in contact with an electrician in the area first sounds like it will save any problems.

You can find a (PART P) registered one at
www.competentperson.co.uk

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Size of cable required

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