The supply to my house uses a TT earthing arrangement. The incoming supply to the house CU (fuse wire holders) is via a standalone Wylex WSES 63/2 63A 30mA RCCB.
Seperate but adjacent to the house CU is a 30A FCU and another Wylex 63A 30mA RCCB that supplies the detached garage CU 11 metres away. Wiring from the RCCB to the garage is via T+E indoors and then MICC/Pyro cable outside.
The outdoor cable is routed to a shed via a double-socket/lighting FCU and then onwards to the garage. The garage CU is therefore not fitted with a RCD, instead it relies on protection from the house board. The shed has no RCD either of course.
I now intend replacing the MICC with 3-core 6mm SWA. Since the earth is already exported, should I continue to keep it this way or isolate the earth and install a local earth rod for the garage? What about the shed too? Perhaps someone could explain the merits of either method to me please?
On a seperate note, should I remove the 30mA RCCB in the house dedicated to the garage and shed, and instead install two RCDs locally within each outbuilding? I can appreciate the merit of it discriminating (is that the correct word?) between shed & garage but I would like to keep cost and hassle to a minimum, assuming it is safe to do so, especially since at present I am only replacing the cable and not changing anything at the CUs (which would be notifiable).
Thanks folks,
Seperate but adjacent to the house CU is a 30A FCU and another Wylex 63A 30mA RCCB that supplies the detached garage CU 11 metres away. Wiring from the RCCB to the garage is via T+E indoors and then MICC/Pyro cable outside.
The outdoor cable is routed to a shed via a double-socket/lighting FCU and then onwards to the garage. The garage CU is therefore not fitted with a RCD, instead it relies on protection from the house board. The shed has no RCD either of course.
I now intend replacing the MICC with 3-core 6mm SWA. Since the earth is already exported, should I continue to keep it this way or isolate the earth and install a local earth rod for the garage? What about the shed too? Perhaps someone could explain the merits of either method to me please?
On a seperate note, should I remove the 30mA RCCB in the house dedicated to the garage and shed, and instead install two RCDs locally within each outbuilding? I can appreciate the merit of it discriminating (is that the correct word?) between shed & garage but I would like to keep cost and hassle to a minimum, assuming it is safe to do so, especially since at present I am only replacing the cable and not changing anything at the CUs (which would be notifiable).
Thanks folks,