>50v on megger when doing ELI test

[Sb8389]

Hi guys
I have had an issue with a couple of sockets in a property when carrying out ELI tests on them saying greater than 50v and won't let me test, some sockets are ok on the same circuit just a couple saying this anybody come across this and understand what it means,I'm using a megger and the system is TNCS

 

[westward10]

Have you checked the sockets internal connections sounds like loss of earth continuity.

 

[telectrix]

loss of earth should bring up the N-PE indicator on a megger. @OP are you sure the MFT indicated > 50V and not < 50V.

 

[westward10]

Not used one of these testers but often a 50v warning indicates a continuity problem.

 

[Sb8389]

Yea greater which is confusing I have done two probe test with no issue at all only happens with 3 lead test

 

[westward10]

Have you retried the sockets which are okay.

 

[telectrix]

sounds weird to me. when performing EFLI test, you should have > 50V, should be 240V. unless it's saying >50V N-E, which could indicate an earth fault.

 

[Specialist]

Think that's what he's saying tel, greater than 50v on the Earth.

 

[westward10]

Have you physically checked to the socket terminals to verify continuity and polarity, if this is okay the socket could have internal corrosion so swap it and retry.

 

[ruston]

On my old Megger seperate it means phase neutral reversed or no earth connection .Also excessive voltage between N+E.
I suppose megger have kept the same convention

 

[telectrix]

the megger mft's have 3 voltage indicators. L-N, L-E and N-E. the first 2 light in normal circumstances, the 3rd only if there is a finite voltage seen N-E and the tester refuses to test.

 

[westward10]

Excessive voltage between N/E generally means no earth.

 

[Sb8389]

Just retested the sockets and all testing ok only since I found a neutral to earth fault on the leg back to mains and disconnected it not sure how this would affect the issue I have had

 

[ruston]

@westward10 It does on mine , along with the others.

 

[westward10]

Just retested the sockets and all testing ok only since I found a neutral to earth fault on the leg back to mains and disconnected it not sure how this would affect the issue I have had

Have you totally isolated the faulty part or just disconnected from the board because if it is the latter the fault would still be there on a ring final.

 

[onions1066]

Didn't you find this fault when you were dead testing though?

 

[westward10]

Don't see how a N/E fault would cause this problem.

 

[onions1066]

I will vouch though the megger can be a temperamental beast. We purchased 30 of them and had no end of problems. They replaced them all in the end and we ended up buying 30 of the flukes as well because all the sparks were moaning about the megger.

 

[telectrix]

Don't see how a N/E fault would cause this problem.

unless there's a poor N or E connection on the supply side or at origin. i recently had a simar fault which was caused by a loose terminal in the head, on the link connecting the N block to the E block.

 

[bigspark17]

Yes this is voltage on the cpc causing the megger to bot start the test.. was there no rcd on the circuit in question?