Light fitting on landing

[dumpty]

Hi all,
Firstly what a find this forum is, a wealth of infomation . Secondly I'm not an electrician but I have done small bits of diy electrical work & am hoping that somebody here, may be able to help/explain something I've come across while refurbing a second property.

While swaping the plastic double switch for a chrome one I noticed that the switch has a green gooey substance around the terminals & one switch was wired in twin & earth with a loop from the C terminal across to the C terminal of the other switch. The other switch (controling the landing light) only had a single red with grey sheath going from L1 to the light.

At the brass landing light I found no earth at all (all other lights & switches are earthed) & the single cable from the switch. Also the light has the same type of single cable connected to the neutral of the light, (this is where it is foxing me) the cable that is connected to the neutral of the light runs directly downstairs to the fuse box & is connected to the earth bar (i found this when I had removed the fuse box cover to wire a socket just below), so now in effect there is an earth (connected to the neutral terminal of light) at the light but no neutral .

I have been out & purchased a multimeter & using a long length of cable ( a helpfull tip given by a B&Q chap in the electrical dept ) I have buzzed out from one end of the cable to the other to confirm that it is the same length of cable between the light & fuse box & which I can confirm it is.

Questions are
1, can I take an earth from the switch up to the light ?
2, Is the single cable allowed to be used ?
3, How did the light work with no neutral ?
4, should I move the single cable in the fuse box from the earth bar to the neutral bar, so giving a neutral at the landing light ?
5, would it have been wired this way at fuse box but not to neutral so an earth would have been at the fitting because it is a brass light

Sorry this has gone on & on any help/advice will be gratefully accepted

Thankyou all
PS I have left the whole lighting circuits turned off just in case.

 

[flameport]

1. Yes, you must do this if you want to keep the brass light. No earth = no metal fittings.
2. Yes.
3. The light worked as the earth and neutral are usually connected either at the entrance to the property, or at the nearest substation. The fact that it worked with that arrangement does not mean it was correct or safe to do so.
4. You can do, but the real question is where the original neutral at the light fitting has gone?
5. The earth would be needed with the brass fitting. Either the person who installed it made a serious error, or someone decided that this was a useful way to get the light working, that someone having no regard for safety.

The green goo in the light suggests that the cable is deteriorating. The plasticiser in some older PVC cables reacts with the copper over time, causing the green mess you have found.