2 x portable work cabin

[baazab]

Hi everyone need help pls

I need to power 2 x portable work cabin

The meter people came today installed new supply with one meter 25 meters away from the 2 cabin

Each cabin have 3 heaters sockets lights

My question is what size Swa cable can I use

Cable length 35 meters from meter box

 

[westward10]

Is this a construction site and are you an electrician.

 

[LukeD]

Is this a construction site and are you an electrician.

This 100%

 

[westward10]

Are you going to embellish us with more information?

 

[baazab]

Is this a construction site and are you an electrician.

Good morning sorry for the late reply

Yes it construction site
Yes I'm approved niceic electrician

 

[James]

It seemed to be a very simple question and because of that I suspect that many people wondered if you were undertaking something outside of your knowledge base And experience.

work cabins in my experience tend to have an appliance inlet on the side and this can vary between 16A and 63A generally.

to be on the cautious side, I would assume the rating of the inlet is the maximum demand.
pick your cable type, probably swa? Have a look at the cable rating tables in the back of the book and post your results here for a double check.

don’t forget to consider earthing type and arrangements or possibly the need for an rcd or 2 of differing types maybe.

 

[timhoward]

It's not really any different from any other circuit design, you need to arrive at what current each unit will draw after some diversity (as the heaters will presumably be thermostatically controlled), then consider how cable is run, and volt drop and fault protection.

(I would suspect these will not be allowed to be connected to TN earthing but I haven't read section 7 and checked. Certainly the mobile/transportable units section would prohibit it, but I'm not familiar with the Construction Sites section)

 

[baazab]

It seemed to be a very simple question and because of that I suspect that many people wondered if you were undertaking something outside of your knowledge base And experience.

work cabins in my experience tend to have an appliance inlet on the side and this can vary between 16A and 63A generally.

to be on the cautious side, I would assume the rating of the inlet is the maximum demand.
pick your cable type, probably swa? Have a look at the cable rating tables in the back of the book and post your results here for a double check.

don’t forget to consider earthing type and arrangements or possibly the need for an rcd or 2 of differing types maybe.

Thank you
Will have to wait and see what the big electricians going to advice me

For example if they say use 2 x 16mm swa to each one this mean I need second electrical box next to the meter with small fusebox to glan the 2x Swa .

I'm confused

It seemed to be a very simple question and because of that I suspect that many people wondered if you were undertaking something outside of your knowledge base And experience.

work cabins in my experience tend to have an appliance inlet on the side and this can vary between 16A and 63A generally.

to be on the cautious side, I would assume the rating of the inlet is the maximum demand.
pick your cable type, probably swa? Have a look at the cable rating tables in the back of the book and post your results here for a double check.

don’t forget to consider earthing type and arrangements or possibly the need for an rcd or 2 of differing types maybe.

 

[baazab]

It seemed to be a very simple question and because of that I suspect that many people wondered if you were undertaking something outside of your knowledge base And experience.

work cabins in my experience tend to have an appliance inlet on the side and this can vary between 16A and 63A generally.

to be on the cautious side, I would assume the rating of the inlet is the maximum demand.
pick your cable type, probably swa? Have a look at the cable rating tables in the back of the book and post your results here for a double check.

don’t forget to consider earthing type and arrangements or possibly the need for an rcd or 2 of differing types maybe.

I agree with you this new to me

To be honest I don't want to do it ,
But if I do it I can have the 14 house later which I love to do empty house rewire that's what I been doing for the last 8 years

 

[westward10]

You need to know the nature of the cabins, office, wc, welfare etc...
The most they will have is a couple of 2kw heaters, lighting and mostly low load appliances apart from a kettle or a few kettles. 16.0 is likely to be overkill.

 

[baazab]

Yes I agree with you few 2 kW heaters and mainly the kettle

its snall cabin mainly use for breaktime

You need to know the nature of the cabins, office, wc, welfare etc...
The most they will have is a couple of 2kw heaters, lighting and mostly low load appliances apart from a kettle or a few kettles. 16.0 is likely to be overkill.

 

[baazab]

16mm swa is way to much but if I decided to use it the system is tnc-s

Reading few minutes ago say cant use the earthing if it Tn system ,I'm confused pls pls
Does this mean I need to install a Earth rod

 

[westward10]

The cabins do not fall under Section 704 so TN-C-S can be used however the supplier may not have provided an earth so it may be TT anyway.

 

[baazab]

The cabins do not fall under Section 704 so TN-C-S can be used however the supplier may not have provided an earth so it may be TT anyway.

Thanks again
It' is tnc-s
100% I checked

 

[timhoward]

The cabins do not fall under Section 704 so TN-C-S can be used however the supplier may not have provided an earth so it may be TT anyway.

I realise it's rarely complied with but would the cabins themselves they not fall under Section 717 wherever they are?
"Unless these installations are under continuous supervision by a skilled or instructed person and the effectiveness of the means of earth has been confirmed prior to connection, TN-C-S systems are prohibited."

 

[westward10]

TN-C-S is not prohibited on a construction site, see 704.411.3.1.
As for the cabins I view Section 717 as cabins which are constantly on the move, cabins on construction sites can stay there for years.

 

[loz2754]

I agree that a cabin used as a canteen does not fall under 704 Construction Sites.

I also agree that under Section 717, Mobile Or Transportable Units, a PME supply may used, if the installation is continuously under the supervision of a skilled or instructed person. It could easily be argued that, as the cabin is associated with a construction site, it is therefore under such supervision.

 

[baazab]

We going to far on this job I need experience electrician to say run the cable put another rod if I have to and get powered
Even if I have to pay him for his correct advice I don't want see section numbers ,

If it can't be done then I just going to pull out

Im sure someone will come and give the correct way

 

[loz2754]

I would suggest in that case that you go ahead pull out, if you're in over your head.
Unless it's possible for a more senior electrician to mentor you on site?

 

[goasis]

I dread to think what the wiring in the 14 houses would look.like if this is such a tricky concept for him to get his head round....

You don't want to see section numbers?!! So what your actually saying is you can't be bothered to educate yourself on this, you just want someone else to do the thinking for you and give you free advise?