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Topic Title: EICR on a caravan
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Created On: 18 June 2017 11:23 AM
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 18 June 2017 11:23 AM
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jonny705

Posts: 157
Joined: 26 September 2015

I asked for some advice about a month ago regarding an EICR on a caravan static mobile home site.

I have done 5 so far and all the vans are passing internally - they are up to 12 years old.
Other than a few minor C3, they have all been wired as to 17th 2008 so D/P 30mA main switch - plastic boards etc.

The common thing they all have is a DIY link between N/E to create own TNC-S system-readings are 0.49/ 0.23/0.45/0.62, there is one that is TNS, but all from same supply! this is 35.6Ohms.
Now I know these are supposed to all be on spikes as Origin from DNO is TNC-S.

So Although the actual vans wiring is fine the relationship to incoming supply is not so , I have put the code as C1.

The other thing none of them have is any local isolation , I have read various information and from what I see they are in breach of most of the 708.55 regs, including not being connected to a PME earthing supply 708.553.1.14.

I had a fault on one of the Main switch RCD'S, it would not do any loop tests, so tried rcd test and tripped, eventually was a able to get a ramp test at 5mV, so replaced the RCD, but had to turn off most of the site to kill mains!

Now I will not be doing any of the new supply work as it's a total hash up , and beyond my experience but I will code this as a C2 on my report .

The last thing , is they are now getting together between themselves and going to dig in their own earth pits /spikes to save money I guess .

Once this is done they want me to connect to spike and C/B with new cable and will obviously re-test ZE/ZS/PFC etc.
As I am changing the main earthing characteristics , I think I should issue a full install certificate, and not a MWC or updated PIR to cover myself , does this sound like a good bad plan?

Oh, and another thing that I cannot work out is, that when you buy these mobile homes, you can spec an halogen hob/electric shower/cooker and A/C , so how would these hook up to a normal 16a outlet that most sites I have read about seem to provide?, the DNO apparently has told the site owner to allow for 3.6kW ,per van, does this seem normal?

Any advise , would be most appreciated
 18 June 2017 05:51 PM
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AJJewsbury

Posts: 16100
Joined: 13 August 2003

I didn't think that 708 applied to supplies to static caravans (nor 721 for that matter) - as I read it it only applies to leisure accommodation vehicles - i.e. tourers, and tents.

(that's in the 17th at least - the 18th DPC seems to suggest a change to that - but that's still academic for the moment at least).

- Andy.
 18 June 2017 09:11 PM
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jonny705

Posts: 157
Joined: 26 September 2015

Well I have just read in some other file that a 'Static Caravans' are Mobile Homes and fall under no special locations rule ,just normal BS 7671, but then have read in that case they should be wired with 60a supplies like a normal house, which would make sense with the potentially load they can now demand, as they are more like bungalows now, than caravans.

But they are still caravans are they not when it comes to no exporting of TNC-S supply etc?

http://webarchive.nationalarch...48&zoom=auto,-144,830

I have just read this above and spoke to the DNO guy about it , as I phoned them for a site visit-and he said they should be TT'd, and it's illegal to create' your own TNC-S supply.

Please tell me if I am correct to code it a C1?

In regards to the no 'local isolation of the supply ' problem , if it's not classed as a caravan ( thus will have a 'normal permanent supply - does that mean it would have a dno cut-out and fuse like I would have in a house, Just mounted in a IP box or something local to van, and as it has none of this is this fair to say it's a C2?

I have found out that once they are sited they become' dwellings' so are subject to council tax, but not classed as a 'building' and are not subject to Part P regulations, just find it all quite confusing TBH

It's a caravan ultimately in my eyes, so would have thought it would still come under section 7 regarding the wiring to it notwithstanding the load problem if they are permanent dwellings with all the normal appliances a small bungalow could have.
 18 June 2017 09:48 PM
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geoffsd

Posts: 1783
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Originally posted by: jonny705

I have found out that once they are sited they become' dwellings' so are subject to council tax, but not classed as a 'building' and are not subject to Part P regulations, just find it all quite confusing TBH

You couldn't make it up, could you?

Either the language does not have enough words, or
those who make the rules should ensure they use the correct ones.



It really is not good enough.
 18 June 2017 10:00 PM
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geoffsd

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Can you still fit plastic CUs in mobile homes - static caravans - as they are obviously not domestic (household) premises?
 18 June 2017 11:47 PM
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mapj1

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Well if you had been replacing an existing but corroded rod with a new one, (or more likely putting a second on along side) that one may argue is minor works. Here you are changing the whole ADS strategy from TN? with MCBs and fuses, to TT and RCDs. And give what you have posted before about the state of the supply wiring , quite correctly so. But I'd consider that now there ae some rcd test reults to add, NE bonds to remove and so on, it is rather more than 'minor works' .
You need to be careful in the description of works not to accidentally adopt responsibility for the stuff that you have no control over, but "convert earthing to true TT , includes fit rod, perform loop test, test RCD, re-energise existing caravan wiring", sounds about the drop.
If it was a (modern) block of flats you would still have local isolation, as cut outs are often cascaded, so there is a fuse in the basement next to the incoming mains (look up Ryefield boxes, but it is essentially a row of house cutout style fuse holders in a box specified to survive a small bomb.) and then in or near the flat or its meter another cut out, but with a 'red link' Which looks like a fuse but is just solid link. Pulling the local red link allows the meter and downstream to be maintained without cutting off more then necessary
The question of load and diversity over a distributed site is also potentially fun - using flats again as a similar case, you may find that the supply to a flat is set at a similar level, about 15A when looking at the incoming cable, even though it splits into many flat supplies of 60A or 80A each.
Observe your local substation transformer sizes, and you will see that while the street cable to each house on a large estate is good for 100A, there may be 50-70 such houses on each phase of a transformer rated at only half a megawatt, so someone assumed a couple of kW each would be enough, for a full house, and by and large, it is. So if you had enough caravans to get some similar smoothing over varying demand, despite having a 63A plug each, the site supply may be sized such that no more than a quarter of this per caravan on average, was expected.
The DNOs normally work to tables of 'ADMD' after diversity, maximum demand, it may be worth a read of local policy.

-------------------------
regards Mike
 19 June 2017 11:06 AM
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jonny705

Posts: 157
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Well regulation 421.1.201 regarding metal boards says about domestic premises, so not caravans.
But as they are 'dwellings' and not subject to 708/721 but to normal bs 7671 regs, are they now considered buildings in relation to metal boards- who knows

All I know is if I had to tell them they had to have their boards changed to metal with a potential plastic one feeding it as well, as no local feeds/ isolation , then ultimately the cost of it , they would be in raptures of not joy but pain.

When I said they need earth stakes/pits, they are all off to screwfix to buy and dig them in by themselves- saves me doing it in this weather - angle grinding slabs out of the way and mixing concrete don't really appeal-and who am I to stop them?
I think a lot would-be under the vans with earth wire trying to poke them into the boards- to save some money, but at least have listened to some advise not to do that!

Have just phoned up Stroma technical line regarding coding query and he agrees C1 and C2 for the failure.

Will complete a full install cert as seems the correct way to go to cover myself for the exact work I have done (which will be connect wire to spike and MET in board) but not digging pit/spike in.

The residents spokesperson says he has been told to allow 36kW for each van, but think he might mean 3.6kw hence normal 16a supply proposed , which is where my confusion arises as the same as a what is in 708 etc , but some have h/hobs and electric showers in them already-but thank the Lord none of that side of it is my concern - was just curious how they work it out
 19 June 2017 12:04 PM
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AJJewsbury

Posts: 16100
Joined: 13 August 2003

I have just read this above and spoke to the DNO guy about it , as I phoned them for a site visit-and he said they should be TT'd, and it's illegal to create' your own TNC-S supply.

That's correct - not just for caravans but for any consumer it's contrary to the (statutory) The Electricity Safety, Quality and Continuity Regulations for a consumer to "combine the neutral and protective functions in a single conductor in his consumer's installation."

- Andy.
 19 June 2017 12:21 PM
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rocknroll

Posts: 9549
Joined: 03 October 2005

I have found out that once they are sited they become' dwellings' so are subject to council tax, but not classed as a 'building' and are not subject to Part P regulations, just find it all quite confusing TBH


Not really confusing, park homes are licensed by the LA and if you can get a copy of the license you will notice that whilst not under the control of BC they come under the guise of the Town & Country Planning and Building Regulations, most licenses state that the design and construction is required to comply with the Building Regulations to ensure the safety, health and welfare of the people who live there, not just electrical safety but things like water quality, drainage, sewage and other waste, insulation and energy efficiency is also considered.

The details on the license normally state that the electrical installations must comply with the latest statutory requirements which is the Building Regulations which in turn references the non-statutory BS7671 as the benchmark.

So whilst the installations are not required to be notified to BC they are required to comply with Part P Electrical Safety as this is the benchmark.

Regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 19 June 2017 04:34 PM
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geoffsd

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Originally posted by: jonny705

Well regulation 421.1.201 regarding metal boards says about domestic premises, so not caravans.

Well, the requirement actually states "domestic (household) premises" so I would agree with you - but is that the case?
 19 June 2017 04:46 PM
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geoffsd

Posts: 1783
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Originally posted by: rocknroll

I have found out that once they are sited they become' dwellings' so are subject to council tax, but not classed as a 'building' and are not subject to Part P regulations, just find it all quite confusing TBH


So whilst the installations are not required to be notified to BC they are required to comply with Part P Electrical Safety as this is the benchmark.


Part P is only a very short sentence related to safety, with which no one can disagree, and nothing to do with the notification requirements.

I would therefore agree with jonny that the application of other Building Regulations is indeed confusing.


Could you please indicate where the rules which apply to dwellings do not apply to static caravans/mobile homes - which are dwellings - because they are not buildings?

Edit - and if so, why this should be the case?
 19 June 2017 06:37 PM
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weirdbeard

Posts: 3116
Joined: 26 September 2011

Some reading for the OP:

http://www.theiet.org/Forums/F...tid=205&threadid=17355

-------------------------
:beer)
 19 June 2017 06:39 PM
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weirdbeard

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 19 June 2017 06:42 PM
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weirdbeard

Posts: 3116
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Etc: Google: "park home site:theiet.org"

-------------------------
:beer)
 19 June 2017 08:41 PM
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jonny705

Posts: 157
Joined: 26 September 2015

Thanks for links have read quite a lot of them already-just adds to the confusion sometimes.

One of them changes from being TT only to being allowed to have PME via the NICEIC advise.

For me , when I spoke to the DNO guys that arrived about 45 minutes after I phoned them in 3 vans, and they said remove bodgy link and TT the things , that's good enough for me, and the only other concern was the C1 coding on the Inspection forms - I was a bit unsure of .

The supply issues won't be my problem , but was just curious how they are done/worked out-seems there is a lot of different methods used , certainly not black and white, anyway, probably will all change with the 18th edition anyway!
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