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Please can anyone help with this:
Mid 1920s 3 bed semi had a professional total rewire last July and is in the process of refurb. Since then everything has been fine until the other night when the ground floor wiring circuit began tripping out after the kitchen light (circular fluourescent) had been on for about 5 minutes. Other ground floor lights don't cause trip-out.
Switch and light fitting connections were tight. Changed fluourescent tube -still trips out after 5 minutes. I changed the fitting for a conventional bulb and holder and the same thing happens.
On checking the wiring in the ceiling rose the only thing amiss was that the earth wire from the light fitting cable had become detached from the loop-in(?) earth wire, however, reconnecting it made no difference to the problem.
A few days before this problem, I noticed a very wobbly section of floorboard in the back bedroom. The cause was a (new) lighting cable coming from a conduit T junction and which had been passed over the top of the conduit so that the cable lay between the conduit and the floorboard, and so the floorboard could not lie flush. With quite some effort and bother, I removed the T piece so that the cable now lies below joist level. I did not cut into or otherwise disconnect the cable, which I am guessing is the supply to the kitchen.

Sounds like the cable that was trapped is now faulty. You have to replace or repair the cable; removing the problem that caused the fault won't cure it.

Stoday, Thanks for advice; I'll give it a try.

Thanks to Stoday pointing me in the right direction the problem is now fixed, but not without some difficulty
Although the cable where I had been working had only superficial scuffing to the sheathing I decided to sever it and insert a junction box. However, there was insufficient free cable to enable this, so I had to remove a section of conduit.
The next conduit junction was about 4 feet away under a different section of floorboard. The attached pic (sorry about the quality) shows what was revealed when I lifted that floorboard. A section of sheathing had been removed from the cable and the cores loosely bound with a piece of red insulation tape, apparently to facilitate insertion into a sharp bend in the conduit. Also, the edge of the conduit had cut through the sheathing and into one of the load-bearing core wires, baring the metal. The conduit is absolutely flush with the top of the joist, so the cable was compressed between the floorboard and the conduit -hence the tripping-out.
I removed some more conduit, severed the cable and inserted another junction box. No more tripping-out.

I'd be tempted to get the Lecky back in, what else has he hidden.

Makes me doubt his overall workmanship, as a DIY Lecky (part 15 trained) I would not leave cables like that anywhere.


John

John, I know what you mean, but would you really want them back? Would you even let them near a battery-powered toy?
That was just (probably) the worst of the list of problems, which have included cut-out floorboards being unsupported when replaced.