Very Strange Lighting Circuit Problem

[squareone]

Dear folks, I am having a very strange problem with 1st floor lighting circuit at home. I hope you could help.

In my investigation the circuit is made up of two rings - circuit A - staircase ceiling light; circuit B - three bedroom ceiling light and bathroom downlights x 4 (GU5.3)+extractor fan.

bathroom downlights and extractor fan each forms a 'branch' from circuit B.

I swapped downlights from halogen to led which is how this problem started.  

The problem is sometimes circuit B will entirely out of work and only recovers about 5-10 minutes later. It is as if there is a surge protection kicks in and has a delay effect on circuit B.

 
Now I disconnected the downlight branch. And the problem still exists.

I have tightened all connectors at junction boxes and checked the connection at the breaker (MCB).

Circuit A is always working ok.

Could someone please explain to me what could be going on here? Thanks a lot

 

[Blue Duck]

lighting circuits are usually "radials" not too sure what your getting at?

the problem is sometimes circuit B will entirely out of work and only recovers about 5-10 minutes later. It is as if there is a surge protection kicks in and has a delay effect on circuit B.

:C

 

[squareone]

I am guessing there is a circuit B - because when it out of work it is always that bed room ceiling lights and the bathroom downlights and fan out of work together. So the radial is applied to when it split into staircase ceiling (circuit A) and the rest (Circuit B)

I also have experiencing at one point a bedroom dimmer has no effect on the bulb it mean to control, but the bathroom downlights!

P.S. In swapping GU5.3 from 20w halogen to LED, now I know I shouldn't have done it.  It has been flickering when there is one 20w halogen + 3x4w led. Each downlight has a transformer which I now know only work for >20w blubs

 

[Andy™]

probably a loose connection somewhere

 

[Sharpend]

So who or when was the dimmer fitted?

 

[SPECIAL LOCATION]

I swapped downlights from halogen to led which is how this problem started.  

Could someone please explain to me what could be going on here? Thanks a lot

Just swapping lamps   i.e.  remove one lamp, put new lamp back into original light fitting...

will not have caused the problem...

Either you have done some other work that you haven't told us about..

or there was already an existing problem...

Are you sure you haven't replaced any light fittings or switches and possible connected a small group of lights off a 'switched live' rather than a 'permanent live'.. 

Or join some rooms up in series rather than parallel!!

so some rooms only operate dimly if both rooms switched on!

:C

 

[ProDave]

This isn't clear but in post #3 is sounds like the bedroom dimmer does not affect the bedroom light, but it dims the bathroom lights?

I would start investigation at that dimmer first, since it's the most obvious place that has been "messed with"

It sounds like it's loop at the switch and what should be the permanent live out to the next room has become the switched (dimmed) output from the dimmer.

 

[squareone]

Wow. I am overwhelmed by your responses, I will take a picture/drawing at the junction box tonight where messed up switching line could be a suspect.

Sharpend: So who or when was the dimmer fitted?

--- The dimmer was fitted long ago and was 'working' - I have been using a not dimm-able bulb and keep the dimmer to the max. My wife accidentally turned it and with all the nightmares that followed.

SPECIAL LOCATION/ProDave: 

Just swapping lamps   i.e.  remove one lamp, put new lamp back into original light fitting...

will not have caused the problem...

Either you have done some other work that you haven't told us about..

or there was already an existing problem...

Are you sure you haven't replaced any light fittings or switches and possible connected a small group of lights off a 'switched live' rather than a 'permanent live'.. 

Or join some rooms up in series rather than parallel!!

so some rooms only operate dimly if both rooms switched on!

--- I replaced the bulb in the bathroom from halogen (20w) to led (4w), I read many suggestion that because GU5.3 has a transformer which requires at least 20w output for it to work, otherwise short led bulb live and flickering - I guess this is not relevant to the problem? Anyway after post my #1 I went back to putting back the halogens, reconnect the bathroom branch it worked last night (all light fittings worked). Only became not working again this morning! (Again, none of the lights or fan work).

It could be an existing problem because what I described here is pretty much the same before/after I started disconnect and reconnect (to my memory) connectors.

I will investigate a possible cause of 'switching live', dimmer and accidental 'series' this evening. Your suggestion sounds plausible.

The thing I found freaky is, you reset the MCB, wait there, expecting lights are back on, it doesn't, and only when your patient runs out after 5 or 10 minutes, it comes on. I didn't touch anything, not a switch during the time. Sometimes it doesn't come on at all. 

 

[Blue Duck]

LED's don't work well with dimmers and transformers and aren't really a direct swap .

You will need a leading or trailing edge dimmer and a driver instead of a transformer.

MR16/GU5.3's LED's are a bit rubbish, to save the cost of all new drivers buy some GU10 lamp holders and swap them for mains voltage LED GU10's which are much better.

Lights problems does sound like a loose connection.

 

[binky]

is there 2 circuit breakers at the board for 2 light ciruits? If not it would suggest cct fault lies between top of stairs light fitting and bedrooms.

 

[squareone]

Binky: There is only one breaker for the 1st floor lighting circuit, which controls both stairs light and the rest. 'cct fault' means?

 

[kerching]

Cct fault =. Circuit fault

 

[Steve3948]

LED's don't work well with dimmers and transformers and aren't really a direct swap .

You will need a leading or trailing edge dimmer and a driver instead of a transformer.

MR16/GU5.3's LED's are a bit rubbish, to save the cost of all new drivers buy some GU10 lamp holders and swap them for mains voltage LED GU10's which are much better.

Lights problems does sound like a loose connection.

Blue Duck, the above is only your opinion you should add.

There are many lamps on market that are sold as a direct replacement for the Halogen mr16, Philips Master LED for one and they are dim and non dim, we have fitted loads with no issues.

The problem with swapping the lamp holder to GU10 is the lamp holder may not fit in the fitting and the additional time and cost removing the transformers could be a factor.

We had a job where all halogen lamps were changed 98 in total, so the additional time spent removing transformers with no benefit but the possibility of damaging the ceiling was good.

3 Years on and all still working.

 

[Blue Duck]

Well yes, but I feel it is better to take the transformer out of the equation.

Less to go wrong :C

Given there isn't much info to go on were all just clutching at straws.

 

[squareone]

After a defeated weekend, I didn't bother to look up the fault again (and felt so much better). So currently it is like this: staircase ceiling (circuit A) working, circuit B: bathroom downlight connected, halogen bulbs (20w) not working - it has been working 'occasionally', extractor fan, bedrooms' ceiling - working. I will report back my progress soon - need to find the strength to crawling in loft first. 

 

[binky]

It's one circuit, think of it as such.

 

[Sharpend]

I'd probably look at the transformers? Have you tested across the output terminals to see if you have the correct output voltage?

 

[Murdoch]

Time to get out the MFT and do some dead tests.....

 

[binky]

time to get an electrician perhaps :innocent

 

[Blue Duck]

Is it just me that can't really understand the problem?

:C