DISTRIBUTOR CANNOT BE TRUSTED...

I'm glad to see you are wearing gloves ? I hope there is someone with you in case you slip with all that exposed live in the box given the complete lack of any protection from the installation itself - I presume the camera operator is briefed on 1st aid ?

I also see you have slipped into the local practice of stuffing the wire ends into the socket to test the lamp. This is scarily like the roughest bits of ost Berlin just after the wall came down, the difference is that in the last 30 odd years that stuff has all been demolished or modernised. (and there red was the earth and black live, usually, but not always.)


Please don't be upset if it seems  I'm teasing you a little bit but I have a serious message - I hope we both know that in the UK  the H & S folk would be having kittens, and this really is not the sort of thing to be undertaken alone or anything other than wide awake and on a good footing in dry shoes.  I might wear also a long sleeved cotton shirt in your place. Consider that if something does go snackle pop in your hand and showers you with hot metal it may be the difference between needing a new shirt and needing a skin graft to your wrist and forearm.  It only needs something to fall onto the incomer terminals...  Even with skeleton substations in the UK, the DNOs now like to see big rubberised sheets draped over the live bits when folk have to work near them on anything else to reduce the risk of things falling into the works.


Now to the results.

Nice to see that some things are earthed, even if the gas main is not really what you want as the only reliable electrode (!!), this result also shows that your substation has an earth as well, which in the circumstances is a good thing to have verified. Normally it goes without saying, but maybe not here.

The impedances to the building re-bar are more than a bit  underwhelming really, so that is clearly not going to serve as a main electrode.


I guess the next one to think about is your water pump - is the incoming service pipe metal ?


Edit sorry, did not answer the original question.

To a small electrode I'd  consider 6mm or 4mm as a minimum - as noted below the resistance of the soil dominates, so the cable size is really set by the mechanics of not getting damaged by rats or the gardener, and not being so big as to look  attractive to thieves. To things that may have an NE bond elsewhere like the water pipes,  for your 32A supply, there is little point in anything more than 10 or 16mm2. Your whole intent is to have double pole breaking RCD cover, so a large enough N-E  diverted current to damage the cable is unlikely even in fault from your side.

You cannot sensibly protect against a fault current coming up the gas pipe and going down the water that is not from your installation, do not try to, just position the bonding for those paths so that if it gets hot it does no damage, and it is likely to be spotted.

I'm well aware that this is not matching the guidance for the UK, by a large margin, but what we need here is safety, not blindly following inappropriate rules


Mike.

I'm glad to see you are wearing gloves ? I hope there is someone with you in case you slip with all that exposed live in the box given the complete lack of any protection from the installation itself - I presume the camera operator is briefed on 1st aid ?

I also see you have slipped into the local practice of stuffing the wire ends into the socket to test the lamp. This is scarily like the roughest bits of ost Berlin just after the wall came down, the difference is that in the last 30 odd years that stuff has all been demolished or modernised. (and there red was the earth and black live, usually, but not always.)


Please don't be upset if it seems  I'm teasing you a little bit but I have a serious message - I hope we both know that in the UK  the H & S folk would be having kittens, and this really is not the sort of thing to be undertaken alone or anything other than wide awake and on a good footing in dry shoes.  I might wear also a long sleeved cotton shirt in your place. Consider that if something does go snackle pop in your hand and showers you with hot metal it may be the difference between needing a new shirt and needing a skin graft to your wrist and forearm.  It only needs something to fall onto the incomer terminals...  Even with skeleton substations in the UK, the DNOs now like to see big rubberised sheets draped over the live bits when folk have to work near them on anything else to reduce the risk of things falling into the works.


Now to the results.

Nice to see that some things are earthed, even if the gas main is not really what you want as the only reliable electrode (!!), this result also shows that your substation has an earth as well, which in the circumstances is a good thing to have verified. Normally it goes without saying, but maybe not here.

The impedances to the building re-bar are more than a bit  underwhelming really, so that is clearly not going to serve as a main electrode.


I guess the next one to think about is your water pump - is the incoming service pipe metal ?


Edit sorry, did not answer the original question.

To a small electrode I'd  consider 6mm or 4mm as a minimum - as noted below the resistance of the soil dominates, so the cable size is really set by the mechanics of not getting damaged by rats or the gardener, and not being so big as to look  attractive to thieves. To things that may have an NE bond elsewhere like the water pipes,  for your 32A supply, there is little point in anything more than 10 or 16mm2. Your whole intent is to have double pole breaking RCD cover, so a large enough N-E  diverted current to damage the cable is unlikely even in fault from your side.

You cannot sensibly protect against a fault current coming up the gas pipe and going down the water that is not from your installation, do not try to, just position the bonding for those paths so that if it gets hot it does no damage, and it is likely to be spotted.

I'm well aware that this is not matching the guidance for the UK, by a large margin, but what we need here is safety, not blindly following inappropriate rules


Mike.