Domestic socket loop test puzzle.

Bobble23 · Nov 11, 2016

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?

Pete999 · Nov 14, 2016

Clutching at straws, but you only have one cable at the socket with the problem, yes? can you gain access or do you know where it is spurred from? if you do can you disconnect that spur cable and check for continuity, making sure the wires are not broken anywhere, I did say clutching at straws that's all I can add.

Jay Sparks · Nov 14, 2016

Pete999 said:
Clutching at straws, but you only have one cable at the socket with the problem, yes? can you gain access or do you know where it is spurred from? if you do can you disconnect that spur cable and check for continuity, making sure the wires are not broken anywhere, I did say clutching at straws that's all I can add.

This is why I tell my apprentices to test at EVERY point on the circuit when doing continuity. Even though you can see the cpc, doesn't mean it's really there! It could be broken inside the sheath (if using multi core of course).

Jay

Bobble23 · Nov 14, 2016

Thanks Pete. I'll try that when I go back but I'm not optimistic - the cpc is there and tests up except when it has any sort of contact with the back box. It's in the kitchen - maybe I should tell the customer to look for a battery-powered toaster!

westward10 · Nov 14, 2016

Give the cpc a good pull, if it comes away there is your problem.

The Ghost · Nov 16, 2016

Have you tried moving the socket about when you test? Clearly there is no logic in

Bobble23 said:
connect with 1mm wire the earth of the socket to the earth terminal

causing a break in the loop. therefore the single you attached has pulled in the socket enough to re-create the pushing the socket back into the box and replicated the same break. And as Westward10 asked "what do you mean voltage on the back box" maybe there is a clue there?