New distribution connection direct to cabin whilst house is demolished scenario

[Torpediniforme]

Rather than have a temporary building supply my customer has agreed with Southern Electricity for them to cut and extend his current supply at the rear of his house which is being demolished.

I am planning on installing a small CU with 30mA RCD main switch and an earth stake since there will be no gas or water to bond to, my thinking for this is so that it can also meet the requirements of a TT site supply and also for if it is fed from the CU in the new house in the future. It

 

[MajorOak]

I would stick a new 4ft earth electrode into the ground close to where the the new meter box is going to go, put an MET in the meter box with a 16mm2 earth conductor from the MET to the new earth electrode. Then a 16mm earth conductor from the MET to the new consumer unit in the cabin. Wire what you need in the cabin then complete an Electrical installation certificate for the new installation. Ensure that the connection to the earth electrode is visible at all times and out of the way of any diggers that could cut through the earth cable.

Southern Electricity will come and move the supply and if it is any form of TN system then they will more than likely connect up their earth to your new MET.

And of course the work registered with the local council either through a scheme or direct.

"they will more than likely connect up their earth to your new MET"

It is not more than likely, its a dead cert!!

 

[Sidewinder]

If the cabin is anything like a caravan, don't think you can have PME, I'd have to look it up, I'm sure one of you will have the reg at the tip of your tongue?...

 

[ProDave]

You say "rather than a temporary building supply".....

But excuse me, what you have described is EXACTLY a temporary building supply, where they provide a feed to a meter and CU in some temporary waterproof box. That can feed caravans, site huts, portacabins etc.

Then when the new house is built, they will come back and re connect the supply to the CU in the new house.

So tell me in what way is this NOT a temporary building site supply?

 

[MajorOak]

The Electricity Safety, Quality and Continuity Regulations deal with PME

Protective multiple earthing

This regulation applies to distributors' low voltage networks in which the neutral and protective functions are combined.

In addition to the neutral with earth connection required under regulation 8(3)(B) a distributor shall ensure that the supply neutral conductor is connected with earth at

 

[Sidewinder]

Major,

I am fully conversant with the ESQCR regs, it is just that my memory is not that good at remembering the detail

Same with the brb, in the UK ESQCR defines PME & TN-C-S as one in the same for new supplies.

Now IIRC it is prohibited to connect to a "caravan" with TN-C-S in the brb & ESQCR, though neither are to hand at the moment, and I ain't looking now as I have a few things to finish off!

A "Portacabin" type building is a very simiar construction to a caravan, also the building will be on a construction site.

Thus it will come under the requirements for electrical distribution on construction sites, also the whole thing will come under CDM regs, thus there will be requirements there also.

It gets very complex and it is not covered by just on paragraph from one set of legislation.

Unless the home owner does ALL and I mean ALL the work themselves and no one attends the property whilst at work then things change, but as soon as one employee attends the site then things are completely different.

 

[Andy™]

read section 704 - mostly the part that says TNCS shall not be used on a construction site, unless to a fixed building

 

[Andy™]

Was this meant to be in the Jokes Thread :slap ROTFWL :slap

it may well be that the cabin can have PME, but since the rest of the site would be TT, may aswell TT the whole lot

 

[MajorOak]

I was taking it as a single supply to a single dwelling. I will hold my hand up and say if it to be classed as a building site then and I am not fully clued up and would then have to go and have a read. This is just what I remembered off the top of my head regarding the ESQCR and earthing. The box on the side of the cabin would be the source of the supply, I wasn't considering any further distribution.

I will shut up now as I may be digging an hole for myself.

 

[ProDave]

It may well be that the supply is to "a single (temporary) dwelling"

But it will also go to any number of caravans, site huts etc, and of course the builders will use it for their tools, etc etc.

So in all but name, it's a building site supply. Exactly what we did 8 years ago.

 

[batty]

TT is safest on construction sites as long as the builder doesn't disconnect earth if its in his way.