Neutral to Earth Fault

[davemorris]

Hi i recently wired a property, i 2nd fixed all the upstairs sockets then tested them, the ring continuity is fine, as is the r1+r2. Phase to neutral is 500 phase to earth is 500 neutral to earth is 0.16. i assumed it was a knick in the neutral touching a socket. Ive taken of all the sockets tested every end of cable and there arent any faults when i put the sockets back on i have a fault again. I know it sounds ovious but could a new socket have such a fault on it to make this occur. Any other suggestions would be great thanks

 

[Darkwood]

If you suspect a socket why not take each socket off then test the the ring from each point then the socket you took off at the terminals their is a chance a grommet may have come out of socket box and when you push the socket back a neutral gets nicked on the cable entry.
Also check your socket screws are not screwing into the neutral wire when you fasten your sockets back.
Note if testing from the sockets to remember to remove neutrals from c.u. block so you dont see the N/E short created by the substations transformer connections ( i assume this isnt what your already seeing and that you took the wires off the neutral and earth bars)

 

[electricAl]

Yeah, could be any of those suggestions by DW, but could you clarify where are you actually measuring your IR - at ends of ring only? or including RCBO etc?

 

[davemorris]

If you suspect a socket why not take each socket off then test the the ring from each point then the socket you took off at the terminals their is a chance a grommet may have come out of socket box and when you push the socket back a neutral gets nicked on the cable entry.
Also check your socket screws are not screwing into the neutral wire when you fasten your sockets back.
Note if testing from the sockets to remember to remove neutrals from c.u. block so you dont see the N/E short created by the substations transformer connections ( i assume this isnt what your already seeing and that you took the wires off the neutral and earth bars)

I still havent fitted the c.u. so that isnt a problem. Ive taken every socket off and tested every end of cable going to the sockets and ends at the c.u. i might try putting all the sockets on but not screwing them back as this maybe the problem.

Yeah, could be any of those suggestions by DW, but could you clarify where are you actually measuring your IR - at ends of ring only? or including RCBO etc?

yes, the c.u isnt fitted yet so im just IR the end of ring only

 

[electricAl]

If you have put the socket plates back on, & there`s a fair few of em...

Split the ring approx in half, & test again.

If IR is all good then you`ve just found THE problem s/o (you`d be so lucky!) but more likely you`ll establish in which half of the ring the problem lies. Split that half again (into 1/4) & so on until you find problem.