Garage supply

[Carpman]

I have recently moved into a new property and noticed that the garage supply cable from the main house CU was wired in 1.5mm SWA current carrying capacity of 21A protected at the Main CU via a 20A circuit breaker.

The garage mini-CU has a 80A main switch with 30mA rcd and serves 1 x 6A MCB lighting CCT and a 32A MCB socket CCT.

I am thinking that there is an issue with discrimination , there are a couple of ways around it that i can think of.

What are you thoughts on this, i know ideally i may have to upgrade the supply cable to the garage CU at some point for furthur expansion.

1. reduce the size of the 32A socket MCB to 16A.

2. Maybe fit an RCBO at the house CU, allowing removal of the 80A RCCB in the min-cu.


your thoughts please.




rgds


Carpman

 

[plugwash]

Personally I would just leave it. Even if you reduce the breaker to 16A you still won't gaurantee discrimination and you will have just added a pointless lower limit on the ammount of power you can use out there. There is no problem with having the RCD protection at the outbuilding end indeed many consider this the preffered configuration.