Earth/neutral fault. need advice

[Stapes88]

Hi guys, just after some advice and reassurance in what I'm doing as not encountered this fault before. So I have an earth/neutral fault.

Plug an appliance in trips in the RCD in the db. I have continuity between earth and neutral in the sockets from different circuits.

Now if I use my IR tester, drop out each neutral one at a time from each circuit and test between this and the earth bar in the board, this will tell me what circuit the fault is on? Then once found simple estimate where the middle of the circuit is and do the same? Go from there til I find the fault in the circuit?

I'm thinking likely a loose neutral connection shorting to earth, or damaged cable somewhere.

Thanks for and help in advance

 

[davesparks]

Did you switch off the main switch or RCD to do the continuity test? If not you may be testing through the N-E link on the supply.

But yes your suggested test method seems right, but be aware that you'll want to switch off all the mcbs to avoid parallel paths via any connected loads

 

[Pete999]

Does the RCD stay ON without any appliances plugged in? or the particular appliance which causes the RCD to trip.

 

[Stapes88]

Ah no, I didn't switch of the main switch actually, and it does stay on when nothings plugged in, also tripped with two different appliances so ruled that out

 

[Pete999]

Ah no, I didn't switch of the main switch actually, and it does stay on when nothings plugged in, also tripped with two different appliances so ruled that out

Plug 1 appliance in at a time

 

[Stapes88]

Plug 1 appliance in at a time

Sorry it was one different appliance at a time, tried both on different circuits

 

[Pete999]

Seems confusing how many Socket circuits do yo have? are they Rings? are they both controlled by the same RCD? how many RCDs are there in your CU?

 

[Stapes88]

Seems confusing how many Socket circuits do yo have? are they Rings? are they both controlled by the same RCD? how many RCDs are there in your CU?

If I remember rightly, there's 4 socket circuits, only one is a ring. Both circuits are controlled by 2 different RCDs, there is work being carried out at the moment replacing old cable, sockets, switches ect, person ran into this problem, rang me and I popped in on the way home

 

[Octopus]

who is said person? a spark? a DIYer?

 

[Stapes88]

Two guys, one spark just out of apprenticeship and and diyer who's done this type of work before. Apparently house had been tested recently and came away fine, however, I'd already found a live neutral switched over in another socket from previous. I think il just have to go through it all in the morning, find out more with what's going on

 

[Pete999]

If I remember rightly, there's 4 socket circuits, only one is a ring. Both circuits are controlled by 2 different RCDs, there is work being carried out at the moment replacing old cable, sockets, switches ect, person ran into this problem, rang me and I popped in on the way home

Stapes your answer doesn't make sense 4 circuits, 1 ring Both circuits??????

 

[davesparks]

4 ci

Stapes your answer doesn't make sense 4 circuits, 1 ring Both circuits??????

4 circuits, 1 of them is a ring, 2 are on RCD a and 2 are on RCD b

 

[westward10]

Does the tripping occur at one of the sockets or several.

 

[Richard Burns]

As you were testing with a neutral earth link outside the supply available and this would give an NE "fault" at all times then it I would say it sounds more like a neutral has been connected to the wrong circuit.
I.e. circuit one has line from circuit 1 and neutral from circuit 2, circuit 2 has line from circuit 2 and neutral from circuit one. This would cause the RCD tripping on load, but would generally trip both RCDs.
To get a link from the neutral on one circuit to the earth on anther would be difficult as earths can easily be linked across circuits and so any such fault would tend to show up on a single circuit.