Type of rcbo for circuits

[ericmark]

However, are there not caravans in which all of the touchable parts are non-conductive (e.g. fibreglass) and, if so, why do special regs apply to hem?

Yes, caravans were made mainly of wood. And even with early metal versions,

the Sprite Ariel was what I started caravaning in, there was no link chassis to body, back then one electric 12 volt light above the door, and main lighting was gas, and no 230 well back then 240 volts was supplied to the caravan.

Where I work, the building is RSJ's with steel cladding, with at least three independent three-phase TN-C-S supplies, which clearly should be outlawed, but in real terms there is that much metal in the ground, 8 miles of railway track to start with, it is highly unlikely even with a loss of PEN the building would raise in polarity to true earth by any significant level.

But the regulations are not doing a risk assessment on every caravan, my father-in-law stated the meter cupboard was 1.5 meters from the caravan, and to have the caravan on a different earthing system to the house was dangerous, and he was likely correct.

But unless like my father-in-law you can show good reason not to comply, then you're stuck, TN-C-S not permitted to caravans and similar items, but for an EV car as long as a loss of PEN detection is used, you can, god knows what regulations cover an EV motor caravan?

 

[morqthana]

A caravan is clearly mobile, calling them static seems wrong, but the main thing is they are made of metal,

Maybe it's a static mobile home made of wood.

 

[JohnW2]

Maybe it's a static mobile home made of wood.

An interesting point is that 'mobile homes' appear to be explicitly excluded from BS 7671's regulations relating to caravans, even though they are usually made of metal and are really just 'caravans with engines'

 

[morqthana]

This is a motorhome

This is a mobile home:

 

[JohnW2]

This is a motorhome ..... This is a mobile home:

Is that how BS 7671 sees things? ....

721.1 Scope
The particular requirements of this section ...... do not apply to the electrical installations of mobile homes, residential park homes or transportable units

Is not your second picture of a "transportable unit'? If so, what is the "mobile home" they also mention?

 

[ericmark]

I was under the impression that changes in BS 7671 now made it clear mobile homes were also prohibited from having a TN-C-S supply, I know years ago many did have a TN-C-S supply, but this is another clarify rather than change, so there is no get out in that it complied when designed.

As to the mobile home , really, do you think one could really move that to another location? Clearly homes can be moved

if one visits the likes of Beamish, most of the building have been moved there from elsewhere, this

is not a mobile church, but it is not its original location. I would call the picture top of page a prefab, not a mobile home, These are mobile homes,

and one could expect them to be moved around a caravan park. But this

is not going to be moved in a hurry. We often see a caravan of mobile homes going through our village, all on wagons, a real pain when they all travel so close together, I tried a Google "difference between caravan and train" but it was a bit useless, we had a caravan of camels, but a train of wagons.

"A building or edifice is an enclosed structure with a roof and walls, usually standing permanently in one place, such as a house or factory." and in the UK we have building regulations, the mobile home gets around building regulations as not classed as a building, planning permission is required for the caravan park, but there is no regulation to say what needs to be in a mobile home, nor do landlord laws cover them. So here is Wales we are seeing landlords move to mobile homes, as they get around so much red tape.

I saw the mobile home first hand in the building of "Sizewell" the problem the site owner had, was the caravan at the time he could get away with a 5 amp supply, but the mobile home he needed a 32 amp supply for. OK, today 16 amp needed for a caravan, and he simply did not have a large enough supply to the site. As it turned out, people were not buying the mobile homes, as to be winterised they were nearly twice the price to summer only ones, and the site only had a temporary all year round licence, so there would be a very low resale value.

But one I suppose must ask, where is this 100 amp supply coming from for this mobile home? The point is if classed as a prefab then comes under building regulations, one can't have both.

 

[flameport]

Is that how BS 7671 sees things? ....

Not really.

Caravans are towed behind another vehicle.
Motor caravans have their own method of propulsion, what most call 'motor homes'
Both covered in 721.

Mobile homes and residential park homes are dwellings which are constructed in a factory far away and transported to their final resting place on a massive truck.
They don't generally move after installation.
They are not covered in 721.

In both cases, the majority of BS7671 applies to them, but in the case of caravans/motor caravans, the specific content of 721 also applies and some of that may differ from other parts of BS7671.

 

[JohnW2]

Not really. Caravans are towed behind another vehicle. Motor caravans have their own method of propulsion, what most call 'motor homes'
Both covered in 721.

Agreed.

Mobile homes and residential park homes are dwellings which are constructed in a factory far away and transported to their final resting place on a massive truck. They don't generally move after installation. They are not covered in 721.

Yes, that's what BS 7671 says. However, as I asked, what is the difference between a "mobile home" and a "transportable unit" (also not within the scope of 721.

In both cases, the majority of BS7671 applies to them, but in the case of caravans/motor caravans, the specific content of 721 also applies and some of that may differ from other parts of BS7671.

Agreed, but in the context of how my question/comment started, that does make a difference in relation to whether or not RCBOs have to have DP switching.

 

[flameport]

what is the difference between a "mobile home" and a "transportable unit"

Mobile homes are transported to their destination, installed, and remain there for years or decades. They have people living in them.

Mobile / transportable units are relocated frequently and do not have people living in them.
Catering wagons, medial screening trucks, temporary offices, displays for promotional events and so on.

 

[JohnW2]

Mobile homes are transported to their destination, installed, and remain there for years or decades. They have people living in them.

OK, but that doesn't sound particularly 'mobile' to me ...the other term BS 7671 uses ("transportable") would seem far more appropriate.

.... Mobile / transportable units are relocated frequently and do not have people living in them.

Fair enough, but BS 7671 does not appear to consider whether or not 'people live in them' when defining the scope of &21 (or 717).

 

[SUNRAY]

Mobile homes are transported to their destination, installed, and remain there for years or decades. They have people living in them.

Mobile / transportable units are relocated frequently and do not have people living in them.
Catering wagons, medial screening trucks, temporary offices, displays for promotional events and so on.

Different experts have differing opinions on what constitutes a mobile home, which is why many (if not most/all) prefabricated and transported homes are wired with stranded wiring.

I have had involvement with 2 EICRs on static mobile homes of this sort of property

which for all intents and purposes are the same as this sort of property

but just finished off a bit posherer and virtually every issue on both was related to being 'Mobile'. Contact with the trade body for the first confirmed the status as 'Mobile' and to be treated as caravan etc. Contacting the manufacturer found their later products were wired accordingly to avoid the ambiguity.

Whether it's right or wrong I don't care, as there is (or possibly has been) ambiguity I'll happily treat them as a caravan when I encounter them.

 

[morqthana]

As to the mobile home View attachment 376280, really, do you think one could really move that to another location?

That really is not the point. It's a legal definition. The one in the photo is, I'm assuming, the maximum size allowed for a mobile home, and all that's required is that it is capable of being moved in one or two sections. It doesn't have to arrive like that - in fact self builders can buy plans for a scratch build which if followed will result in a structure capable of being moved.

It doesn't matter if you'd need a vehicle larger and heavier that anything which could get anywhere near the site.

It doesn't matter if you'd need an enormous crane to lift it over trees and other buildings, which itself could get nowhere near.

If, as a structure, it's no bigger than 20m x 6.something, and is capable of being moved, it's a mobile home.

 

[bernardgreen]

If, as a structure, it's no bigger than 20m x 6.something, and is capable of being moved, it's a mobile home.

Would this be classified as a mobile barn

 

[morqthana]

It's clearly mobile. Looks too wide to qualify as a mobile home in the UK.