Yes, I think you read the question essentially correctly. Something, assumed to probably be the outside installation, has caused an RCD to operate, taking out the freezer, once last year and once this year, and the OP was asking if there is some device which could prevent an outside fault killing the freezer.I totally agree one needs to locate the fault and correct. Maybe I have read the question wrong but what I read the question as was how do I stop a fault in the future from tripping my fridge/freezer supply. ... However well one tries to water proof an out doors supply there is always the chance of water ingress and the resulting earth leakage. ... I would agree that a 10 mA RCD may not trip before the 30 mA trip so I was looking for a cure.
If one were designing from scratch, the solution would obviously be simple enough - simply to arrange things such that the freezer and outside wiring did not share the same RCD/RCBO - either by having them protected by different RCDs or for one of them to have its own RCBO, fed from a non-RCD protected supply. Whether any of those solutions could easily be implemented in the OPs home we don’t know; he was obviously hoping that there would just be some device that could protect the outdoor supply and discriminate reliably against the RCD protecting the freezer etc. - which we are agreed is not possible.
Quite. I don’t think the OP was suggesting that the pump, per se, caused the trip - indeed, there’s no reason why torrential rain should affect something which is already submerged Rather, I think he was suggesting that other things in the outdoor wiring (switches, JBs) had been affected by the severe rain.Personally I had a pond with pump no longer running and while in use it never caused my RCD's to trip. Many other faults caused them to trip but not the pond.
Quite so. If it’s only happened twice so far (once during a holiday), the chances of it happening again during a holiday are probably very small - quite probably little/no greater than the risk of the freezer itself failing. As I’ve said before, I seem to have been very ‘lucky’ with RCDs/RCBOs. I have lived with something like 12 of them for many years and there have been few, if any, occasions on which one has tripped without good reason, nor have any of the ‘with good reason’ trips ever happened when the house was unoccupied for a significant period of time.I have not had a RCD trip while on holiday causing the freezer to fail. I have had a freezer fail while on holiday but it was freezer motor not the RCD which caused it. I was lucky I caught it before everything was spoilt but the question is for one holiday a year does one install isolation transformers or RCBO's or simply have insurance?
Kind Regards, John