None Ring

[NoSparks]

During a PIR I recently found a ring where the cpc did not form a ring when measured at a socket (though the line and nutral were ok). The remedial work included replacing the CU and of course during its replacement I checked the ring at the CU. OK now, and realistic values for r1, r2 and r n. I then had occation to recheck the circuit at the same socket still no ring for the cpc. The term bridging comes to mind, but what explanation would you give and what would you do next.

 

[nickblake]

this should be done at the CU R1 ,R2, Rn then the R1R2 crossed legs at the CU , what you are describing sounds to me like a spur off the ring main that has lost its cpc connection , further investigation is required for this obviosuley you test to ensure the sockets are correct which should be done at each socket to ensure correct polarity and that the socket is wired correctly

 

[Deleted member 9648]

Carry out R1R2 tests with the Lives and earths cross connected,all readings on ringed sockets should be identical.
If there are any issues the readings will differ.....go from there.

 

[NoSparks]

Unfortunately my faith in the "figure 8" approach has been seriously undermined over the years with such results as 0.2 and 0.7 which you might think was a spure, but in fact were the two adjacent outlets in a brand new twin socket.

None the less its a good thought to go back and re-check the the "figure 8" results.