I have recently had installed a new beafed up supply to an outbuilding to supply an electric shower, lighting etc and hookups to caravans.
The main dedicated feed from my main incoming supply is via a 30mA DP 63A RCBO and 10mm SWA cable to a new CU with a 100A DP RCBO. The 4 way hookup box is fed from this CU via a 32A MCB and then via 16A MCB to each individual hookup.
Due to recent power outage (momentary cut) the 63A RCBO in the house has tripped. This was reset without any problems but if we had not been available in the house the caravan occupiers had no access to reset this switch. But they do have access to the CU in the outhouse. How do I get this to trip first rather than the one in the house? At the moment the caravan hookup box does not have an RCBO. Would installing one solve the problem. ie this would then be the first to trip and what should the rating be - 32A ??