Sorry about that ,, I meant two way switching requiring a third wire, possibly a bare earth wire in an old circuit.. could the rcd be picking up on that,,?
This circuit,,
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What if one could identify that earth and disconnect it..?
I assume it is a line leakage, possibly one that has been there since the house was built..
The light has not been used for a long while now..
I would need to switch my pc off and put a bulb in to check what happens..
I have a vague memory of having to fix a fuse, a long while ago, could it have been when a bulb blew,
That sounds like an RCD then, is it possible the lighting fault started when the RCD was fitted, not when the central heating was fitted? Are all circuits in the house going through the RCD, or just some of them?
When people have been referring to 'borrowed neutrals' they mean that e.g. as in your case the live for the landing light is taken from one circuit, but the neutral for it is taken from a nearby circuit that is more convenient, but nevertheless the wrong one - an RCD can "see" this as a fault.
As others have hinted, I don't think you have the knowledge to fix the problem, but at least you are in a better position to explain to an electrician that "the RCD trips when the landing light is used" rather than "the tripper trips".
If do you feel you need to fix it yourself rather than get someone in, it's not impossible to learn, but suggest you read through archives here for safe working, RCDs, two-way switching, borrowed neutrals, and old house wiring, take photos of everything before you touch it and ask again regarding what you intend to do ...
So,, two lighting circuits,, with the positive feed from the downstairs circuit.
With a borrowed neutral from another circuit,, Every thing is hunky dory-until i swtch the upstait hall light on and the rcg takes a hissy fit because he aint connected to that circuit as well...
The Rcd is supposed to be connected to the downstairs lights and bathroom fan alone,,
Surely, the borrowed negative being used, will be borrowed from the upstairs light circuit.
Where will an electrician have picked up the wrong negative,, fusebox or in the loft,,
What if the two lighting circuits were made common,,?
With a fused RCD spur for the downstairs bathroom fan and lights.
same as this one..
Power Breaker H92WP-C White RCD Fused Spur unit,
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When I switch the upstairs hall light on, the breaker trips which puts the downstair lights off and the fan in bathroom...
This only happens when there is a bulb in the holder,,
Certainly, there could be some old wiring that needs replacing as in old style braided dropper wires,or maybe the plumber damaged some wiring,,
I favour the borrowed negative theory at this time. So far, ive had a wee look in the light switches for clues, downstairs double switch live feed jumped over from downstairs hall light
Ive not located negative connection yet..
I suspect, probably from the upstairs light circuit..
.. Im considering this Proposed action,
temporarily disconnect negative from upstairs light circuit at the fuse box.
Switch the light on and see what happens.. Obviously,, I would not expect the light to come on, but if the tripper did not go off..
Would that not indicate that the borrowed negative had been identified'' ?
On Sunday, November 16, 2014 6:43:47 PM UTC, nuther didint post link,,
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To reach the ceiling rose and replace the old fittings and wires, would require a plank over the staircase onto a pair of steps, with no parachute..! it certainly needs doing, but it might not fix the problem..
There was previously two lighting circuits each with its own fuse, and no RCD.
When the shower fan etc was installed it needed RCD protection, and since it was to be powered form the downstairs lighting circuit (as is common with fans that need triggering from the lighswitch), they had to install a RCD spur, and connect the whole lighting circuit to it. So far so good, it means the fan and the downstairs lights are now all RCD protected.
However, the downstairs lighting circuit also feeds a lamp upstairs, and alas the neutral connected to the same lamp returns directly to the fuse box without going through the RCD. So the moment the light turns on (and there is a bulb in there). the live connection to it comes via the downstairs circuit and hence the RCD, and the neutral was probably connected to the upstairs lighting circuit that is not connected via the RCD. Hence the RCD sees and imbalance. and does what it is designed to do and trips.
It won't be visible at the switch - that normally only has live and switched live. However if there is only one live in (and the jumper wire is a big clue) then it suggests the live from one circuit only is being connected to both switches.
Quite possible. Also possible the RCD actually feeds the fusebox and the 1950s wiring is kaput. We're not going to know until the OP gives us the requested info.
If it is a borrowed neutral problem (from a 2nd lighting circuit), putting both lighting ccts onto the RCDed feed would solve it. If its not a 5/6/10A circuit you'd also need a fuse for it.
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