cable to an outbuilding

[JACKC]

Just a quickie as not 100% sure on this. Old house with lots of code 1's on PIR. Supply to detached garage is in plastic conduit buried in ground. 30 amp fuse from house supplying garage fuseboard fed in 2.5mm singles. No earth from house fusebox but garage is TT, house is TNS. I have reconnected this as part of ongoing project into a 20 amp mcb but not sure if it needs an earth cable running in the conduit. Not wanting to export the house earth but can not see the point of running an earth down the conduit to protect the singles supplying the garage board. The garage is going to be upgraded asap but still doing house at the moment. Mental blockage at the mo so another point of view would be appreciatted.
Thanks

 

[Taylortwocities]

Surely you'll not be leaving the plastic conduit there? Won't you be installing SWA?

 

[holmslaw]

..

 

[ricicle]

PVC conduit with singles in is not the correct way to run a buried sub-main. Earthed SWA is the most effective way of running a buried supply, albeit only earthed at the supply end if you are creating TT at the garage for whatever reason.

Would you honestly want to leave it like that seeing as you have now taken responsibilty for it ?

 

[Chri5]

It's very quite

 

[viewer]

Ricicle spot on advice; earth is terminated at garage end, armour is earth at supply end but you now have to create a TT system for the garage. Perhaps worth checking that you can get a decent earth and where is the best place for the rod before going further as it could dictate the layout in the garage.