A residential park home is there and listed within the scope of the section and yet. Of a time some time ago a decision was made that the external supply point to a caravan (or similar) requires a 30mA RCD. A decision was made yet what is of more interest and indeed offers more understanding is the reason for the decision. The answer is almost always in the reason for the decision. Now I am not privy to any such discussions, oh if only we had a wiring regs equivalent of Hansards it would be wonderful. Yet consider what we know.

Is the concern for compliance with the letter of the regulations or some other issue? Mobile or static, A static in which folk reside, lets call them all one and the same for the sake of this response. Usually limited to 16A connection perhaps we may see a 32A connection. If so the external supply position as supplied is fitted with either a 16A or a 32 A 60309 socket. By this the supply is usually connect to the accomodation by a flexible cable. Be nice if it was HO7-RNF. What do we know about sockets?

In this case you have a 40A connection which would suggest a 'hard wired' connection to the accomodation. Is it a flex, swa or some other? Does the cable run from the external supply point to the internal consumer unit within the walls of the caravan? If it does and it's flex well, caravan site, or similar, or not, the general body of the regs still apply.

WHat about that 6A circuit does that require a 30mA rcd?

What is the earthing system on the site? Is this of relevance in the need for the dual RCD's.Why make a point of grouping all such under the 'or similar locations' banner well the possibility of dual earthing systems at play TN-C-S and TT would be one reason for such.

Then we have the manufacturer who wires the caravan / mobile home. They can only cater for what they know. They do not know the details of the site on which  the unit will in time be sited. For this reason they can only record the results of the 'dead' tests on the van at the time of the electrical install. Why 30mA rcd backed up with 30mA rcd, well the internal rcd can be easily explained.

Engineering decisions. In this case what purpose would replacing the 100mA rcd with a 30mA serve? Are there any factors, aside from a debate on a definition of a location, that by their impact would make life so much easier and require that the 100mA RCD be replaced with a 30mA rcd? That is after all the essence of the question.

Conjecture yes of course. What if the resident was an elderly person and on a dark wet winters night they trip. No lights. A nusiance trip is a nusiance ever more if you slip and break a hip. Electrical safety is paramount and as part of that we look to minimise nusiance and unwanted loss of circuits.

A residential park home is there and listed within the scope of the section and yet. Of a time some time ago a decision was made that the external supply point to a caravan (or similar) requires a 30mA RCD. A decision was made yet what is of more interest and indeed offers more understanding is the reason for the decision. The answer is almost always in the reason for the decision. Now I am not privy to any such discussions, oh if only we had a wiring regs equivalent of Hansards it would be wonderful. Yet consider what we know.

Is the concern for compliance with the letter of the regulations or some other issue? Mobile or static, A static in which folk reside, lets call them all one and the same for the sake of this response. Usually limited to 16A connection perhaps we may see a 32A connection. If so the external supply position as supplied is fitted with either a 16A or a 32 A 60309 socket. By this the supply is usually connect to the accomodation by a flexible cable. Be nice if it was HO7-RNF. What do we know about sockets?

In this case you have a 40A connection which would suggest a 'hard wired' connection to the accomodation. Is it a flex, swa or some other? Does the cable run from the external supply point to the internal consumer unit within the walls of the caravan? If it does and it's flex well, caravan site, or similar, or not, the general body of the regs still apply.

WHat about that 6A circuit does that require a 30mA rcd?

What is the earthing system on the site? Is this of relevance in the need for the dual RCD's.Why make a point of grouping all such under the 'or similar locations' banner well the possibility of dual earthing systems at play TN-C-S and TT would be one reason for such.

Then we have the manufacturer who wires the caravan / mobile home. They can only cater for what they know. They do not know the details of the site on which  the unit will in time be sited. For this reason they can only record the results of the 'dead' tests on the van at the time of the electrical install. Why 30mA rcd backed up with 30mA rcd, well the internal rcd can be easily explained.

Engineering decisions. In this case what purpose would replacing the 100mA rcd with a 30mA serve? Are there any factors, aside from a debate on a definition of a location, that by their impact would make life so much easier and require that the 100mA RCD be replaced with a 30mA rcd? That is after all the essence of the question.

Conjecture yes of course. What if the resident was an elderly person and on a dark wet winters night they trip. No lights. A nusiance trip is a nusiance ever more if you slip and break a hip. Electrical safety is paramount and as part of that we look to minimise nusiance and unwanted loss of circuits.

These units are delivered to site on the bed of an HGV. From the HGV they are wheeled by aid of tractor or similar to the pitch. The pitch may be hardstanding concrete, gravel or earth. By the side of the pitch is the external supply position.

The manufacturers provide a plug for connection to this supply point. Often a 16 A or perhaps a 32A  60309 plug connected to a flex that runs into the van. Sockets require additional protection by way of RCD and the pitch supply position provides such by way of 708.
The flex runs up into the van to the internal consumer unit within the walls of the van, this would require additional protection by way of RCD.
The manufacturer builds perhaps 1000's of units that will be sited and connected to a supply unknown to them. Without 708.1 what would they do?

The pitch power supply position is set up to cater for a statics but such could be of all ages and change throughout the life of the pitch. Without 708 what would you have?

As I have said several times in this thread, 708.1 applies to the distribution system on that site NOT the home sited. The home is caught under the general mass of bs 7671.
On these caravan / leisure accomodation vehicle sites a range of units could be positioned and such need safe electrical systems. This is where electrical engineering judgment kicks in, it kicks in against the distribution system on that site and the mix of units / vehicles / homes that are manufactured to an industry spec knowing they can be supplied safe for continued use once sited. Without 708 we would not have this.

Perhaps one answer lies with the licensing authories who need issue licence for each site. They under consultation with suitably experience  electrical engineers / designers designate by way of licence if the requirements of 708 apply to the site or perhaps suitably segregated sections of that site. The connection to these units by way of the distribution system shared is the point of relevance.

Without such a licence framework or the seemingly catch all of 'similar' in 708 there would be manufacturers supply units that require additional protection rcd's but onsite are pitched without.
Same applies to those whom  purchase a secondhand unit and site on a pitch owned by a site owner more often than not with no electrical knowledge. It is a dynamic environment that must be kept electrical safe and 708 ALONG WITH sound engineering decisions can achieve that.