@Colin Haggett 

What are the requirements for 30 mA RCD protection for the circuit supplied from the B6 MCB?

That does the street light outside. 

Have 411.3.4 and/or 714.411.3.4 been considered?

Have 411.3.4 and/or 714.411.3.4 been considered?

Thought it's not really household and street lighting is excluded from 714.411.3.4.

  - Andy.

1. It’s a proper lamppost so shouldn’t require RCD protection. I really want to know if a Residential Park Home which is sited in a purely residential park should meet 708.415.1.for its fixed connection. I would have said no but it really depends on what is meant by similar locations and why should a residential park be treated different to a mixed one. At some point here they all had 30mA RCDs fitted as to 708.415.1

If the 30 mA RCD protection had not been removed from both the park home and exterior light there would not be an issue with the RCD protection for either of them, but it has so both of them have now need to be considered as potentially having issues.

BS7671 gives a definition of a  Residential Park Home on page 42: A factory produced relocatable dwelling designed for permanent residence which may be used for leisure purposes.

708.415.1 says the supply to a residential park home shall have a double pole 30 mA RCD.

411.3.4 says domestic lighting shall have 30 mA RCD protection.

714.411.3.4 says lighting accessible to the public shall have 30 mA RCD protection.

There isn’t any benefit from having that upstream RCD rated at 100 mA as it is not time delayed and will generally trip at the same time as a downstream 30 mA RCD, so it’s not complying with 531.3.2 any more than having a 30 mA RCD does.

So less protection without any apparent benefits and possible multiple contraventions of the Wiring Regulations.

I’ll let you decide.

Edit- not forgetting 536.4.203 components from different manufacturers, Contactum RCD and Legrand MCBs in an unknown consumer unit.

If the 30 mA RCD protection had not been removed from both the park home and exterior light there would not be an issue with the RCD protection for either of them, but it has so both of them have now need to be considered as potentially having issues.

BS7671 gives a definition of a  Residential Park Home on page 42: A factory produced relocatable dwelling designed for permanent residence which may be used for leisure purposes.

708.415.1 says the supply to a residential park home shall have a double pole 30 mA RCD.

411.3.4 says domestic lighting shall have 30 mA RCD protection.

714.411.3.4 says lighting accessible to the public shall have 30 mA RCD protection.

There isn’t any benefit from having that upstream RCD rated at 100 mA as it is not time delayed and will generally trip at the same time as a downstream 30 mA RCD, so it’s not complying with 531.3.2 any more than having a 30 mA RCD does.

So less protection without any apparent benefits and possible multiple contraventions of the Wiring Regulations.

I’ll let you decide.

Edit- not forgetting 536.4.203 components from different manufacturers, Contactum RCD and Legrand MCBs in an unknown consumer unit.

708.415.1 says the supply to a residential park home shall have a double pole 30 mA RCD.

But only if it's on a caravan/camping park (or similar) (from the scope of section 708) - and the definition of caravan/camping park is something having two or more caravan or tent pitches - which doesn't seem to include this site. (hence the original question)

411.3.4 says domestic lighting shall have 30 mA RCD protection.

But it's not domestic (household) lighting.

714.411.3.4 says lighting accessible to the public shall have 30 mA RCD protection.

But not things falling under part (v) - so not for street lighting.

   - Andy.

As in my earlier reply:

Tom J256 said:

708.1 relates only to the distribution circuits. And it is the distribution and the associated earthing arrangments that I believe is the reason why residential park homes (which are not leisure accomodation or caravans) are in that paragraph that reads: 'In caravan parks , camping parks and similar'.

The similar being the distribution system feeding them. Only my understanding of course

The general body of 7671 applies to the electrical installation within the residential park home and the other considerations are then outlined, as per my first post.

708.1 relates only to the distribution circuits.

I'm not sure I follow your thinking. Caravan parks in general certainly contain final circuits (by definition whatever supplies a socket outlet, such as on a EHU, must be a final circuit, ditto any site lighting circuits) - and many of the provisions (e.g. 708.415.1) explicitly mention final circuits and others (e.g. 708.521.7.2 for depth of buried cables) must surely apply to final circuits just as much as distribution circuits. It may be that in the case of the usual EHU box, the final circuit to the socket is entirely contained within that box, but it's still there and still part of the site's installation, to my mind.

I can see the point that a caravan connected via a bit of flex that's directly terminated into the box rather than by a commando plug & socket could be argued as not being a final circuit (by the normal definitions at least, but wording of the 2nd paragraph of 708.415.1 would seem to assume otherwise). I suppose it depends on whether you consider a caravan as a whole as being an item of current using equipment. (Whatever's inside the caravan is out of scope of the park's installation after all). We've had the same debate over 19" racks which may have their own internal power distribution & protective devices.

Having seen quite a few statics that are connected by a length of arctic flex - sometimes by plug & socket to a tourer type EHU, sometimes with just a stuffing gland into a very similar type of box, I do take Mike's point that the risk to the flex (e.g. from grass cutting machines) in the fixed connection case is pretty much identical to the plug & socket case - so 30mA RCD additional protection would be sensible. SWA direct into the home, would be much less of a risk.

   - Andy.

Andy you are quite correct and it was indeed the note under 708.415.1 that was in my mind and lost in my sloppy definition.
By that I mean the hook up point / external electrical supply point which supplies the units, positioned often aside the lodge static is part of the distribution assembly. Thanks to the regulation the 30mA rcd is in place at the end of the distribution position ready for final connection. This becomes a uniform known position against which the units to be sited can be manufactured against. It is the position adopted by site owners in that they take responsibility for the electrical services only up to this point of connection. From that point on it is the owner of the units responsibility. Certainly on E.I.C.R.s  of the caravan I would include the flex and plug to the hook up / connection position.

With these units the site network operator does not bring a supply direct into the unit terminating in a service head. It will often be a looped supply to an external position and from this point the static / tourer / residential home is connected.
708.521.7.2 which you mention refers to the underground distribution circuit that would feed the pillar.

So yes 708 does give mention to final circuits but it is my understanding this helps define the distinction between the distribution assets within the designated licensed area that is the site (could be wrong of course and often pleased to be so).