Just had an outbuilding converted to an office and am putting in a new CU for the 3 scokets and lights. Also linking to this is an amoured cable to take power to a garage some 30m away.
I have two questions please:
1) The amoured cable is four core and the way it was wired before two were used for the live and two for the neutral - does it not have an earth?
2) Do I need to earth the new CU? Obviously all the earths from the ring mains and lights are connected in the unit but do I then need to run an earth cable from this? If so can I attach this to a copper oil tank pipe which is partially submerged in concrete or do I need an earth rod?
The CU in the garage has no earth running to it so same question applies here please.