Domestic socket loop test puzzle.

[Bobble23]

Hi, I don't know if anyone can help with this. A customer called me out saying that a British Gas boiler service had highlighted a socket showing >2000 on the EFLI test. I went to look and got 1.12 on one side of the (two gang) socket and >2000 on the other. I assumed it was a dodgy socket and replaced it.

Testing the replacement I'm now getting about 1.15 as a loop test when the socket's off the wall but >2000 once I screw it in. I can't find any voltage on the back box.

Any ideas please?

 

[Leesparkykent]

Is this a ring final circuit? If it is have you confirmed continuity end to ends?

 

[westward10]

Somehow earth continuity is breaking down. What do you mean by can't find voltage on the back box.

 

[NDG Elecs]

All I can think of is a dodgy connection on the different test lead or plug adaptor thingy. So you are getting decent-ish reading on the conductors, but a crap reading through a new socket, so have assumed you are using an additional test adaptor or a change of leads to do that test.

 

[Richard Burns]

The initial fault sounds strange as it is difficult to disconnect the earthing from one side of socket but I suppose it is possible, it is more likely (but still unlikely) to have been a damaged earth connector at the socket, e.g. pushed to one side by the plug pin.

Once the socket front has been replaced I woudl assume that there is a poor connection to the earth terminal, perhaps the sleeving is caught on the screw, such that when the conductors are moved as the socket is screwed back the earth disconnects. This would be much more likely if both cpcs are in the same terminal or there is an earth discontinuity on one leg of the ring.

 

[Pat H]

Sounds like the first socket must have been faulty. But the change as the socket is screwed in must be a break in the CPC (s) surely?

 

[stevethesparks]

Maybe the cpc is nor continuous and the leg that does appear to be working has a break in it of which is aggravated when the outlet is pushed into place?

 

[The Ghost]

Are you using plug method and on L-PE? and as others said is it a ring circuit? And what was the gas man doing a loop test for ????

 

[Toneyz]

Are you using plug method and on L-PE? and as others said is it a ring circuit? And what was the gas man doing a loop test for ????

B.G did this with socket tester when they came to service our boiler asked why he said to prove boiler had earth (boiler on own circuit radial)

 

[The Ghost]

This whole thing dont make sense. If the boiler is on own radial then it has a spur yes? Where does the socket come into it? But anyway clearly the earth makes and breaks when the wires are in different position. And anyway a socket tester will not give you an ohmic measurement. Confused I am.

 

[NDG Elecs]

The socket tester that BG used was probably one of those that give a very rough idea of efli: there is one that has measurements something like <1; <5; >5 ohms. So when BG 'measure' it, there is no leeway for TT earthing.

To the OP, is the socket on a stud wall with a socket on the other side of the wall perhaps. The act of screwing back the face plate could be pushing the cable/conductors at an adjacent socket out of position.

Also test the R1 value with the face plate back, as it could be that and not the R2 causing the issue. Although I would suspect the CPC to be the cause.

 

[westward10]

Is there a name for people who start threads and then decide not to respond to anyone's replies.

 

[The Ghost]

Annoying?

 

[Andy78]

Is there a name for people who start threads and then decide not to respond to anyone's replies.

Yes, but the auto filter won't let you write it.

 

[GMES]

He could also have a social life unlike us sad sacks.