# Blinking light !!!!!!!! (That shouldnt be)



## Mrplodd (Mar 4, 2008)

I have a VERY strange thing happening with one of the lights in my house.

Its the landing light so its on a two switch system (off or on from either switch)

It is fitted with an LED light as is the rest of the house.

Every so often (at random times) the LED light starts flashing at about 1 flash per second. 

This is when the switches are in the off position and the light has been off for some time.

If I switch the light on it illuminates as it should, switch it off and its flashes !!!

I have tried replacing the LED with an identical lamp and the replacement still flashes.

If I use an incandescent bulb it doesnt flash.

If I take the bulb out and replace it later it doesnt flash when replaced but at some time in the future it starts up again. 

Bizarre or what? 

I have had the switch covers off to check that the wiring is secure and no bare cables etc. 

This is the only light in the house that does it, the lounge lighting and kitchen are on a similar 2 switch circuit and they dont flash.

I have been in the house 5 years and this started about 3 days ago. the house is only 16 years old and the wiring is all in excellent condition.

I have solar panels so I disconnected them to see if that made a difference, it doesnt.

So good people has anyone else had this problem and if so do you know what the cause was??

I am totally and utterly at a loss to work out what could be causing this to happen, its only just started, its intermittent, it happens at random times, nothing with the house electricals has been altered or changed. The only thing I can think of is that a small current is somehow being induced into the cable feeding the lights, just enough to cause it to flash but where the ***** can that current be induced from??? 

Any ideas ?????

Andy:


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## philoaks (Sep 2, 2008)

This may help Andy.

http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=42344


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## listerdiesel (Aug 3, 2012)

Because you're working on a 2-way switch system with a long cable run, it is most likely that you have sufficient induced voltage in the cables to trigger the LED's.

Not enough to light them but just enough to cause them to flash on briefly.

Peter


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## Mrplodd (Mar 4, 2008)

Phil

Thanks for the link, looks like I am not alone!!! I have a pal who is a sparky, I'll get him to fit a resistor (I'm ok with plugs etc but when it comes to other stuff I leave well alone) 

Peter

Thats what I thought BUT these lamps have been in for well over a year and this issue has only just started !!! Nothing has been altered or changed in the house.

Andy


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## listerdiesel (Aug 3, 2012)

Possibly you've got a capacitor gone a bit leaky, all sorts of stuff in there to go wrong.

Our good friend in the USA is on this side of things but he is on the design side for LED lighting, and it surprises me the hoops they have to jump through to comply with various regulations.

I'll mention it when he calls, he's on the phone most evenings.

Peter


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## Mrplodd (Mar 4, 2008)

Peter

I initially thought that the LED lamp was faulty, but I have 4 of that type in the house. WHEN the problem is present each lamp behaves the same and flashes but ONLY in the landing light fitting !!

Andy


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## Pat-H (Oct 30, 2009)

If its not the lamps that have changed then there must be a subtle change in the cable.
As mentioned with a 2 way switch you have cables running next to each other between the switches and that can allow enough inductance for some current to flow in an adjacent cable.
There are a whole lot of things that could have caused that to change slightly. Maybe its a bit damper or maybe something metal is near the cables or maybe an earth has come loose somewhere.
A resistor in the light socket should shunt away that small bit of leakage.


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## Pudsey_Bear (Sep 25, 2008)

Could it be working similar to a flasher relay where some thing get hot, moves then cools, and does it over and over, have you tried changing the holder to isolate that?


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## icer (Dec 11, 2006)

Interesting reading and thanks for the link.
Had a power cut a few months ago and one of my landing lights a led GU10 stayed on for 20 mins but very low light. the other on same circuit did not.
2 switches either end

Ian


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## Spacerunner (Mar 18, 2006)

Maybe you need an exorcist!


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## Pudsey_Bear (Sep 25, 2008)

Spacerunner said:


> Maybe you need an exorcist!


It'd be cheaper and easier to get one than a bloody Sparky.


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## pippin (Nov 15, 2007)

Electrorcist? Might specialise in these problems!


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## Mrplodd (Mar 4, 2008)

Spacerunner said:


> Maybe you need an exorcist!


Hadnt really considered that :wink2:

Kev

It flashes about once a second and, in order to heat up that quickly it would require some serious current AND it only flashes when switched OFF !!!

I had a long hard think about what might have changed in the house and I remembered that I had put a (plastic) suitcase in the loft and, in order to do so had moved an old (metal) telescope and tripod. Double checked and I had lain the telescope directly over where the cable feeding the landing light was.

Telescope duly moved :nerd:

Light no longer flashing !!!!!!!!!!!!!!!!!!!!!!!!!!!! (so far anyway)

(I wonder if they could be "connected" :wink2::wink2::wink2

Andy


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## Pudsey_Bear (Sep 25, 2008)

Woo Woo eh


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## Pat-H (Oct 30, 2009)

Mrplodd said:


> Hadnt really considered that :wink2:
> 
> Kev
> 
> ...


That's an interesting result. The met must been acting as a sort of transformer. collecting the slight electromagnetic radiation and re-distributing it.

The interesting trick now would be to see if you could a coil winding to collect next doors stray radiation and use that to power your LED lights for free.


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## Spacerunner (Mar 18, 2006)

Mrplodd said:


> Hadnt really considered that :wink2:
> 
> Kev
> 
> ...


By 'they', do you mean....


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## pippin (Nov 15, 2007)

Some people who live under huge power lines did try that trick.

Dunno if it works though.

Doubt if it would power a storage heater but with the low currents used by LEDs - worth a try!


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## Mrplodd (Mar 4, 2008)

Arghhhh !!!!

Its "blinking" well started up again !!!!!

Having put my thinking hat on (and used it) I THINK I might have come up with the cause.

I have solar panels fitted and the cable from the inverter (in the loft) to the meter (outside wall) is the outside of the wall of the stairwell and the cable from the switch in the hallway runs up through the same wall SO its POSSIBLE that the current going "down" the outside of the wall from the inverter (230V) is inducing a very small current in the cable going "up" the wall on the inside. The cables do not run parallel though, the solar panel feed is vertical and the lighting cable (I assume) is at an angle to get from the switch in the hall to the light on the landing.

The only fly in the ointment for that is that at the moment the output from the panels is only about 65% (2.2Kw) of the (3.6Kw) maximum (its cloudy) I have not noticed the liamp flashing when the panels have been at max output.

Bloody strange or what????

Andy


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## pippin (Nov 15, 2007)

Andy - I would patent the effect ASAP, you never know - there might be a profit in it someday!


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## powerplus (Oct 6, 2014)

hi andy

we also have a flashing led on the landing not allways be it can be noticed when it is dark


spoke to a sparky and this is known about it is not the first one he has come across and the wiring is fine

he thinks the internals of the led are weak and showing this problem he said put a standard lamp in and forget about it if it is concerning me

barry


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