Caravan width limitation for towing is just about to be increased, this month I think.
Oh that will mess things up. Many caravans will now fail PIR tests as wired in twin and earth.
The supply and caravan MUST be protected with an RCD so there are two RCD's one either end of blue lead. Also will need 16A MCB as well the problem is RCD must switch all live wires i.e. Line and Neutral so twin pole is required. A box with a twin pole RCBO B16 is norm supply end.
If the SWA went into the caravan then it would be different and the caravan would be under same rules as house. But as you describe the caravan could be unplugged and the socket used for lawn mower so it needs RCD protection.
Although it is "Static" it depends on if it can be towed and be compliant with road traffic act and not the way it is used. If it does not comply with RTA then you get other problems like planning permission as it is then classed as a building even though temporary.
If all wired in flex then no real problem for tester it is where twin and earth have been used that it becomes a problem and the tester has to decide if a building or caravan and on that if compliant or not.
Insurance would need to be for professional indemnity the normal public liability would not really cover and as a result you may find it hard to get some one willing to sign the certificates.
Without seeing the set-up it is really impossible to say which set of rules would apply. The fact the council are asking for them I would assume they are classing you as static as with a touring van can't really see what it has to do with them!
In which case it would be like any house once every 10 years or change of owner. You would then also come under Part P in England and Wales and could have a TN-C-S supply.
If classed as a caravan then a TN-C-S supply would break the laws and since a TN-S supply can't be verified it would need a TT supply and earth rods. It would be unusual for a PUB to have a TT supply so again tester would need to be very careful.
It is very unlikely that the set-up you have detailed will pass all points with a PIR but a PIR does not fail as such but highlights the faults with a number system 1 to 4 where 1 means dangerous should be switched off and 4 means not technicality correct to latest regulations but no real danger.
Very few premises will get clean bill of health and so to have faults is normal and not a fail which then leaves it to you to decide what if anything needs correcting.
The only illegal item would be supply and if it is a TN-C-S (PME) supply then that would break the law. This could be a problem as we then start to look at voltage gradient and if there is enough distance between the TN-C-S supply and TT supply to be safe. i.e. no one can touch something earthed from both supplies at the same time.
Hence it needs some one on site to work it all out a forum is not really the place.
