ELV regulations or guidelines, if any?

[SparkyTris]

Is there a "definitive" and/or "authoritative" set of regulations applicable to UK/Europe/The World regarding wiring of mobile units such as caravans, yachts, powerboats, fishing boats, portakabins where the supply is primarily ELV (12 or 24V)

I'm after a document (ideally a book to buy) in the same vein as the OSG which gives the reg and the "one way of satisfying this requirement is...." practical guidelines.

maybe there is no such document.

maybe there are no such regulations...?

anyone reccomend a forum?

 

[EFLImpudence]

I'm after a document (ideally a book to buy) in the same vein as the OSG which gives the reg and the "one way of satisfying this requirement is...." practical guidelines.

Very poor aspiration.

Do you realise that "one way of satisfying this requirement is...." means worst case scenario rather than doing it properly.

 

[PrenticeBoyofDerry]

I think C&G now do an accreditation on the electrics within Caravans/Motor Homes!
Maybe that is the way to go?

 

[ericmark]

What you are asking is there something with ELV which could mean I have to attend court.

What ever the voltage fire can result and to no protect against over current leaves one open.

I remember using pneumatic work lights which had a generator directly coupled to a bulb so there was no chance of a spark. But these were for use inside vessels or large tanks and in normal circumstances one would not require such measures.

So yes there are regulations the RCD (Recreational craft directive) lays down many requirements for boats.

The BS7671:2008 also lays down regulations for caravans.

Some seem daft like the minimum battery size and minimum patch cable length. Why one should not have less than 25 meters I can't work out.

But BS7671:2008 is not law but can be used in a court of law. So it is really a case of don't do anything dangerous. In the main unless a unit goes on fire no one will worry. So for 12 - 24 volt main thing is ensure nothing you do is likely to cause a fire.

 

[SparkyTris]

Do you realise that "one way of satisfying this requirement is...." means worst case scenario rather than doing it properly.

I disagree

The exemplum reg that springs to mind instantly runs sthg like this: Control gear should be installed so that it is operable by persons with limited reach. One way of satisfying this requirement is to install sockets at 400mm above floor and switches at 110mm..." (or something like that).

Personally I find it an efficient way of illuminating regs that are often written in spare semi-legalese so as to interpret them for lesser mortals such as myself.

With reference to that exemplum, I might well have misinterpreted the PC "limited reach" euphemism, and installed all the switches and sockets in the standard 1950 locations of 1" off the deck for the sockets, and at adult neck height for the switches.

By reading the "one way of satisfying this is", I know how to play the game with regards to that rule.

OK, that one is a fatuous rule and has no practicable relevance to electrical hazard. But, having read the OSG, and having examined a lot of pro's work, I can see that the "one way of satisfying this requirement is" methods are followed very much more frequently than I would expect for "worst case scenarios".

Is BS:7671, like the driving test, a minimum requirement?

 

[john4703]

The OP asked for a forum about caravans and this is one http://www.ukcampsite.co.uk/ and http://www.swift-talk.co.uk/ is another. Both have folk on who will give good advice.

 

[westie101]

Or this one: - http://www.caravantalk.co.uk/community/

 

[EFLImpudence]

Do you realise that "one way of satisfying this requirement is...." means worst case scenario rather than doing it properly.

I disagree

Ok.

The exemplum reg that springs to mind instantly runs sthg like this: Control gear should be installed so that it is operable by persons with limited reach. One way of satisfying this requirement is to install sockets at 400mm above floor and switches at 110mm..." (or something like that).

Not sure what an exemplum reg. is.
Is that in the OSG?
If it says should it's not a reg.

Personally I find it an efficient way of illuminating regs that are often written in spare semi-legalese so as to interpret them for lesser mortals such as myself.

I think you have stumbled upon the reason for its existence.

With reference to that exemplum, I might well have misinterpreted the PC "limited reach" euphemism, and installed all the switches and sockets in the standard 1950 locations of 1" off the deck for the sockets, and at adult neck height for the switches.

So?

By reading the "one way of satisfying this is", I know how to play the game with regards to that rule.

It will merely be the worst case - as I said.

OK, that one is a fatuous rule and has no practicable relevance to electrical hazard. But, having read the OSG, and having examined a lot of pro's work, I can see that the "one way of satisfying this requirement is" methods are followed very much more frequently than I would expect for "worst case scenarios".

No, that's what they are.
E.g. if you can't work it out for yourself use X which will cover all scenarios, therefore...

Is BS:7671, like the driving test, a minimum requirement?

Well, in a way, yes - but minimum to ensure safety.

 

[SparkyTris]

What you are asking is there something with ELV which could mean I have to attend court.

Yes I am!

I am also very interested in best theory and practice regarding ELV on mobile units so that I can back up why something "looks bad" with why something might be bad.

For instance,
What, if anything, is wrong with using a mains MCB panel as a distribution board on a 24V boat?

 

[ban-all-sheds]

That's easy.

It's not expensive enough.

 

[Simon35]

What you are asking is there something with ELV which could mean I have to attend court.

Yes I am!

I am also very interested in best theory and practice regarding ELV on mobile units so that I can back up why something "looks bad" with why something might be bad.

For instance,
What, if anything, is wrong with using a mains MCB panel as a distribution board on a 24V boat?

How is the 24V derived on a boat? From batteries charged by the engine like a car?

 

[ericmark]

For instance,
What, if anything, is wrong with using a mains MCB panel as a distribution board on a 24V boat?

Cost. With mains we want disconnect times in milliseconds or seconds with 24 volt as long as it disconnects before a fire is caused that is enough. An overload like this

is good enough for 24 volt.

Durite or Gorden Equipment likely do a whole range of protective equipment suitable for a boat.

Oddly even with a 24 volt system you can get nasty shocks. Back EMF and disconnected alternators can easy give 240 volt. But in the main it is only fire we worry about. This includes the routes wires take. For example they will not go through any box with gas bottles.

I know the RCD exists but I have never read through it. That is what you need to read for boats.

 

[plugwash]

What, if anything, is wrong with using a mains MCB panel as a distribution board on a 24V boat?

The main questions I would have.

1: are the switches capable of safely switching 24V DC systems and are the MCBS capable of safely breaking 24V DC short circuits. On the one hand DC is far more prone to sustaining arcs than AC, on the other hand the voltage and fault currents are much lower. I expect it would be ok but i'd want confirmation from the manufacturer that the breakers were suitable for such use.
2: is the overall current rating of the board appropriate. High power ELV systems can easilly go well over 100A.
3: what is the volt drop of the breakers like. A volt drop that is negligable at 240V could be problematic at 24V (though this is more of a functionality consideration than a safety one)

 

[ericmark]

Good point A 30A trip seems rather expensive at £34.25 I had not looked at low voltage versions.

Here it is a lot cheaper look the same at under £5 and headed Dumper Electrics so one would assume also low voltage DC.

Be it a fuse box or trip I would want to use the small thermal only units rather than the larger thermal/magnetic units. I would worry with magnetic trips that the parts become permanent magnetised and start tripping for no good reason.