Earthing arrangements

[roukel01]

Hello All

Been to inspect a property today. Basically a very large extension has been built onto the side of a house. From the main CU a 10mm twin and earth has been run to feed a new CU for all circuits in the extension.

The Bond to the oil line is fed via 10mm single from the new CU, however, the only earth back to the mains is via the earth in the 10mm twin cable. (think its 4.0mm but it could be 6??)

So do I give this a code 2??

Thanks

 

[telectrix]

agree a code 2. needs a 10mm running back to MET.

 

[roukel01]

Cheers for that,
I forgot to mention. What do you folks put in a PIR when a ring circuit is too long?? There was 1 ring circuit in the extension feeding all sockets, the runs must be huge. Earth loop was slightly high, but was protected by RCD, however it is much more than the recommended 100m2 floor space and the length of circuit stated in the onsite guide.

 

[telectrix]

that one might just be a code 4. if the loading is small. however, i would not be happy with an EFLI in excess of the BRB max. maybe reduce the MCB to 20A, load permitting.