Hi Treblid
Yes anything you can do to keep the soil moist around the earth stake(s) is good. (dripping taps are too expensive if you are paying the bill) I would also check the connection has not badly oxidised (rusted - corroded) as cheaper earth stakes are steel cored with a copper cladding. I have the connections on mine covered in self amalgemating tape to exclude moisture and air, that way the connection does not start to break down once made. There is usually a tally plate where the WA registered electrician stamps his number, thus meeting local regs for its implementation and testing.
RCD - residual current devices, hmmm depends on make and sensititiy, they measure an imbalance between the live and neutral from memory, unlike the ELCB which measures the leakage to earth. If you have to ask about having potentially 'live' screens on mains hook ups never mind the RCD KICKING IN - I will have to come round and
kick your arse personnaly real hard.
Message understood? Yes it should be insulated and you are more than likely breaking some paper shuffling beaurocrats rules regarding mains feeds!
The cheapest mains feed upgrade is to buy a rubber insulated 30 amp cable usually destined to run a higher current load industrially, its quite and ear opener what this simple and cheap change can make, trying to make you own cables is fine for interconnects and speaker feeds but when dicking around with mains voltages things start to get serious very quickly indeed and the potential consequences do not bear thinking about. Please take this in the manner in which its intended!
V