Up until now every installation I've worked on has involved the C.U being within 3m of the supply.
The job I'm working on at the moment is a domestic rewire that has had the supply moved to a box on the outside of the property, and the new C.U will be in a utility room about 4 - 5m away from the supply.
The supply is TN-S with a BS 1361 100 a main fuse fitted. What I'm planning on doing is installing a metal clad 80 A switch fuse at the supply. The customer has already had a 2 core 25mm SWA cable run from the supply box to the new C.U location.
No separate Main Earth has been run with the SWA to the new C.U position though which is my main concern - though after doing some research it seems to be indicated that using the steel armour of the SWA as the main earth should be fine so long as it's PVC SWA (PDF linked below has a useful table):
http://www.earthingnuts.co.uk/pdf/pvc_xlpe.pdf
If anyone here has experience with this and could confirm either way that'd be great.
If it is compliant, my next question would be how to correctly terminate either end of the SWA to the MET and C.U Earthing terminal - I'm thinking of using a banjo along with a couple of short lengths of 16mm.
EZ.
The job I'm working on at the moment is a domestic rewire that has had the supply moved to a box on the outside of the property, and the new C.U will be in a utility room about 4 - 5m away from the supply.
The supply is TN-S with a BS 1361 100 a main fuse fitted. What I'm planning on doing is installing a metal clad 80 A switch fuse at the supply. The customer has already had a 2 core 25mm SWA cable run from the supply box to the new C.U location.
No separate Main Earth has been run with the SWA to the new C.U position though which is my main concern - though after doing some research it seems to be indicated that using the steel armour of the SWA as the main earth should be fine so long as it's PVC SWA (PDF linked below has a useful table):
http://www.earthingnuts.co.uk/pdf/pvc_xlpe.pdf
If anyone here has experience with this and could confirm either way that'd be great.
If it is compliant, my next question would be how to correctly terminate either end of the SWA to the MET and C.U Earthing terminal - I'm thinking of using a banjo along with a couple of short lengths of 16mm.
EZ.
