Light not working on 2way circuit....any ideas/help?

[Frank5533]

2 lights top and bottom of stairs. 2 light switches one at the top other at the bottom.
Problem is the bottom light works fine for awhile then it doesn't. It has kinda flickered, before not working on previous occasions. I've noted the wiring on each switch and as of now (with the bottom light not working) also noted down the live state of each wire. I have made a diagram which I hope will help. When I turn on lights (bottom not working) the screws holding the plastic switch casing on the bottom light switch show power on my screwdriver tester.
I've shown which wires show light on my tester when lights are OFF because when lights are turned ON every wire lights my tester!
Any ideas on what my problem might be would be much appreciated.
Thanks Frank.

PS I have put image of wiring onto an album like it told me to do..not sure if it will link into this post directly....sorry I'm new to this forum.

2way lighting problem

• Frank5533
• 2 Oct 2008
• 1

 

[ericmark]

The lights seem to be wired by an amateur one would not normally supply a second light in that way. Also the two way is wired opposite way around to that normally used in UK. It will work but requires connector blocks in switch box. Also you show earths as disconnected and at times live.
With that in mind I would suggest you get someone in as shock risk and EMC too high to direct a DIYer to try to repair.
Eric

 

[electronicsuk]

Step one, read this information regarding neon screwdrivers. As you have found, they do not give a reliable indication of whether or not voltage is present as the load of the neon is simply too small, and it will light at far below 230v. Induction and capacitive coupling between cores in the same cable means that one of these neon testers can show a cable as being live when, in fact, only the adjacent cable is live.

Step two, sort out your earthing arrangements. For the same reasons as above, potential is being induced into the disconnected CPC (earth) wire. It should be connected in any case, otherwise a fault inside the light switch could lead to any exposed metal parts becoming live, and the same for the light fittings too. As you do not have the tools to test for a good earth path back to the consumer unit, at this point I would suggest bringing in an electrician who will be able to sort this out for you.

As for the actual problem in hand, you could have a loose wire somewhere, or it could be a problem with the lamp. I assume you've actually tried changing it? Could be that as the filament heats up, you're getting an intermittent fault somewhere.

 

[ban-all-sheds]

EMC too high to direct a DIYer to try to repair.
Eric

Electro-Magnetic Compatibility?

 

[Frank5533]

Thanks for replies I was hoping for a quick fix.... "Oh its ya thingy thats wotsit" etc. but alas.
The circuit goes on stairs that link upto a loft conversion that was done 15ish years ago methinks.
As for Earth wires not connected on the upstairs switch, its all plastic (box and switch cover). Downstairs is metal box (this has earths from both cables screwed to it) and plastic cover.
I have changed bottom lamps/rose all are new. This rose only had one cable to it, the upstairs lamp/rose has 3 cables.
Its as if there is a loose wire somewhere which I'm prepared to reconnect whilst power is OFF at fusebox. I'm prepared to try and trace route from lower light to switch/Junction box.
Neon screwdriver info seems very noteworthy thanks for the headsup on that.
Its not all about trying to save money. I am actually interested to find a cure.
I'm not about to take risks with electrics with the little knowledge I am have/gaining.
Any road up... Thanks again for your replies, any other ideas etc. very welcome.
Frank.