Upstairs lights keep tripping

[dmcg14]

It would seem you've got the white core going to the neutral of the lampholder, and the blacks going to the live of the lampholder.

White is switched live,
and the blacks should be the neutral.

This shouldn't cause the RCD to trip though.

Make sure there are no wires shorting together, or against any metalwork like the conduit/fixing screws.

The connections that i posted where the ones i wrote down when i first disconnected the lights. Once i find the fault i'll re-terminate white (switch live) to live of lampholder and black to the neutral of lamp holder

Thanks

 

[dmcg14]

Have you worked on or disturbed any switches?

Any lights etc outside getting wet inside?

I don't have any lights outside, and having checked all fittings for water ingress, i can eliminate this. I've removed the front plates of 2 switches but haven't disconnected any cores

 

[dmcg14]

Can anyone shed any light on why i only have 1 neutral, but 2 earths at my top hall ceiling rose?

 

[sparkwright]

Can anyone shed any light on why i only have 1 neutral, but 2 earths at my top hall ceiling rose?

Yes, because it's wired in singles in conduit.

The one neutral is probably the end of the circuit, and possibly the earth carries on to the switch (for example).

 

[dmcg14]

To update this, I now have all lights working with the RCD now not tripping. I traced the fault to an unused light switch for a porch light that was joined into the circuit inside a junction box. The cores inside the blanked off light switch were touching the back box so in turn tripping the RCD.

Now going back to the original fault, where the breaker tripped for no apparent reason before i touched the ceiling roses. This problem is now back. I've disconnected the main neutral inside the CU and it still trips. I've taken out all light bulbs to no avail also.

Any ideas what could be wrong?

 

[EFLImpudence]

Live to Earth fault.

 

[dmcg14]

Live to Earth fault.

And what is the most efficient way to fault find this?

 

[EFLImpudence]

Is the MCB still taking a while to trip or

can you not reset it at all?

 

[dmcg14]

I can reset it it and sometimes it will trip after 5 seconds and sometimes it will take 10 minutes to trip but its never lasted more than 10 minutes

 

[EFLImpudence]

These (sort of) intermittent faults can be quite difficult to find.
You really need an Insulation Resistance test meter.

You may be able to find it with a Continuity meter (between L and E) or
by narrowing it down by disconnecting part of the circuit.

There could be a Live wire trapped behind a switch screw.

I don't suppose you are overloading the circuit.

It's not impossible that the MCB is faulty.

 

[Spark123]

Keeping on resetting the MCB serves no purpose and could result in making things worse.
House wiring system is pretty simple, I too have a HNC in E/E engineering and the course did not cover anything to do with fault finding wiring systems like this.
If you do not have access to an Insulation Resistance tester (500v) and do not know how to use one, get an electrician in who does.

 

[dmcg14]

I don't suppose you are overloading the circuit.

It's not impossible that the MCB is faulty.

I changed over the MCB to a spare one to no avail.

I don't understand how i can be overloading the circuit given that i have not added any additional fittings, and have no bulbs in any of the fittings

 

[dmcg14]

If you do not have access to an Insulation Resistance tester (500v) and do not know how to use one, get an electrician in who does.

I have access to a meggar, but if the results of the test are below 0.5Mohms, what would be the steps in finding the location of the fault?

 

[Spark123]

Anything less than 5MΩ needs investigating.
Work out your cable runs and use the half split method.