I am not an electrician, but the only opportunity to bond a touring caravan is to the chassis. Though, I do not remember ever remember seeing a connection on mine. I have though heard of some who adding an earthing rod to permanently sited vans.
Other than that, surely just a matter of checking continuity.
The earth's integrity will, I feel sure, be checked as part of a service.
John
EDIT. after a little research I find that earthing rods are NOT a good plan when RCD’s are used.
John , spot on .
I think the jury is still out and like you I am no qualified spark.
A chap on another caravan forum, no names , posted this a while back. One or two on here will fully comprehend what he says.BTW he is a fully qualified spark.
”
Many people plug in their caravans without thought for this, but if you are providing a supply specifically for a caravan then yes, it shouldn't be connected to a PME earthing setup.
Regarding why:
On a TNCS earthed supply there can be a difference in potential between the combined installation Neutral and Earth and real earth due the return neutral current.
Inside a house this is relatively safe.
Outside there are two particular scenarios to consider:
1 - standing on real earth and touching anything earthed can give a tingle. Not dangerous, but un-nerving!
2 - very rare scenario, but if the supply Neutral breaks, then worst case the turn Neutral current goes to the cutout, is linked to earth, and is then looking for a return path through everything that is earthed. The degree to which it will find one depends on each unique situation, e.g. whether there's a metal bonded water pipe. But standing outside on real earth and touching anything earthed is worst-case putting 230v between your hand and your feet with you in the middle as you could be the return path.
So on caravan sites, and supplies to caravans, the installation earth is not connected to the caravan earth, to avoid these scenario's happening.”
I hope this makes sense. DD