Intermittent light fault?

[Lusi83]

So 2 lights (stair and landing) controlled by two switches -one at top of stairs and one at bottom either switch should (I think) turn both lights on.

Top switch is a one gang , bottom one is a three gang (also controls hall light and outside light)

Recently noticed that sometimes the stair light doesn't come on...landing light always does
Have been trying to work out if it depends on the order it has been switched on/off/ which switch has been used but can't seemed to find a pattern... maybe it has always been like this ...

Stair light will originally have been high up and has been lowered by previous owner (Mr Bodge it - experience has taught me to call him) Did noticed this light not working years ago but I think it just kept blowing (enclosed fitting, pre low energy bulbs and maybe should have had a smaller wattage) - I put a temporary fitting on and then this new one following the wiring as it was about 8 years ago and have only just noticed the problem ...
Just looked at switches/fitting etc to check for loose wires etc ...this is what I have - they all have earths plus
//media.diynot.com/39000_38899_55357_77342024_thumb.jpg
One gang switch has a red wire into top part of switch and a blue and a yellow going into bottom
//media.diynot.com/39000_38899_55355_39897154_thumb.jpg
Three gang switch (on this gang) has a red going into top and blue and yellow into bottom
//media.diynot.com/39000_38899_55356_86178179_thumb.jpg //media.diynot.com/39000_38899_55358_50913964_thumb.jpg
Light fitting has a red to live, blue to neutral and a yellow wire cut off inside the cable
(Landing light has standard black and red feeds)
Have taken photos as well and will post them but struggling to get a good one of the light fitting - have looked at diagrams but getting myself in a muddle
So
Does this seem right?
Could it just be a faulty switch? (They are original 1960s)
No signs of sparking etc on any of the wires or any loose...

 

[EFLImpudence]

If I have understood correctly then -

If two lights are wired so that they both should work at the same time but sometimes one doesn't, then there is obviously something loose at the faulty one (or possibly the wire to it at the other light).

 

[Lusi83]

Thanks - the more I have thought about it the more that seems the only explanation ...but the light fitting seems ok...so it must be the feed to that...I guess this could be dangerous ...

Thinking there must be some kind of junction box in the attic? (As landing light has black and red feed, both switches red, yellow and blue and dodgy light fitting blue, red and cut off yellow... ) still can't quite get my head around how this is working - but remember I checked that the blue was neutral/red was live when I put the light fitting on... (maybe even posted on here about it)

I am assuming the cable for this light was just some he had hanging around -hence the cut off yellow cable -what worries me most is how he has joined this to the original feed - hopefully not just somewhere in wall - the cable feeding this light fitting is barely covered with plaster and possibly coming in at an angle - I didn't want to mess up the decor so just connected to what was there!) Think I need to investigate in the attic but all a bit of a mess up there - random boarded areas and the whole lot hidden under insulation...and junk...
(Really don't want to have to dig plaster off walls in this house when I have a half-refurbished one that I want to get into and should be working on!)

 

[EFLImpudence]

Yes, because both the switches have Red/Yellow/Blue there must be at leas one junction box.

 

[Lusi83]

New development -
3 gang switch just failed to operate both lights - as I was going upstairs to see if the other switch would work my daughter (helpfully ) flicked the switch again - the landing light came on but the stair light hasn't and won't (again) no matter which of the switches I use...
Don't know if that narrows it down at all or not - really confused now...

 

[PrenticeBoyofDerry]

Likely that a connection has become loose, whilst you had taken off /refitted switch plates.

So can you clarify this:
You have a single switch upstairs, this switch turns landing light on only or both landing and hall?

You have 3 gang switch downstairs, for outside, landing and hall lights.
But one switch will turn both landing and hall lights on or both landing and hall light work off separate switches?

 

[PrenticeBoyofDerry]

Also are upstairs and downstairs on separate circuits?

 

[Lusi83]

Stairs are split ones - have a half landing - so 3 lights - landing light (at top) stair light (half landing) and hall light (downstairs)
Switch at top - single gang controls landing and stair light
Switch at bottom - three gang - one gang outside light, one gang hall and third gang landing and stair light ... this gang has one cable feeding it with four wires (red, blue & yellow and (un-sleeved -guess I should deal with that- attached to back box) earth ...
Didn't disconnect any wires - just took plates down and wriggled wires...lights have worked after I put plates back on...
(although have never noticed both lights not working before - new development)
Have two circuits (trip switches) - up and down lights - landing light is on up circuit, hall light is on down - don't know about stair light cos can't get it to work at moment...
(should have said had modern consumer unit fitted a couple of years ago and although a blown bulb has tripped it in the past -this problem doesn't)

 

[PrenticeBoyofDerry]

So the problem is the stair light, that is normally activated with when landing light is switched on?
If so it could be that a cable has been run between both landing light and stair light.
You picture of the fitting are a bit blurry and cannot make much out.

 

[Lusi83]

Yep that's it - and sometimes like now I can't get it to come on but other times it works normally...

 

[PrenticeBoyofDerry]

If you only have red and black cables at landing light, this suggest as early mentioned(ELFI) that a junction box is within the void.
How many red and black cables are at the landing fitting?

 

[Lusi83]

Just one black and one red...

 

[PrenticeBoyofDerry]

You will have additional joints, likely to be in the ceiling void above the landing! were reds, black, blue, and yellow cables meet.
Do have any means of testing for continuity and voltage, such as a multi-meter?
I would recommend you check for voltage at stair light when the landing light is on and also for continuity of the neutral conductor between the two lights, second test will require the circuit be isolated prior to testing.
This could throw up some possibilities.
How old is the light fitting?

 

[Lusi83]

I have a basic multimeter - one with a dial (not digital) ...
Assuming I check voltage from light bulb thread not terminals...
Not sure how to test for continuity of neutral conductor between the lights? Can't really isolate anything now - children around (distraction and electricity don't mix!) and have to go out shortly to take one to dance class - will have to do tomorrow ...and will also get up into attic and see if I can find a junction box...

Light fitting isn't old - maybe a couple of years? ...Sorry - really struggled to get a good picture...no real natural light ...

And as I said in (long! ) first post - this light would originally have been higher up wall -maybe even from ceiling and previous owner (Mr. Bodge- it) would have moved it to present position to make bulb changing easier - that would have been 10+ yrs ago - but I do dread to think how/where he joined it up ...(just his electrical additions include a cupboard light switched neutral, eave cupboard lights metal switch, no earth and a double socket I am almost certain is spurred from the lighting circuit )

 

[PrenticeBoyofDerry]

Screw in lamp/bulb at stair light is this firmly screwed in?
Sometimes if not they will not work!
Test for voltage between live and neutral at the terminals of stair light.