Problem Manifesting Itself In 2-Way Lighting Circuit

[Wuffles]

Hi all.

So. I'm getting some kind of spike (for want of a better word) appear in a couple of lighting circuits, BUT only when they are wired as 2-way. When they are 1-way they behave as expected. Wire either of them as 2-way and with the use of a single LED wired into the lamp wires it'll flash momentarily every few seconds whilst the circuit is off. When it's on it works as you'd expect.

Now I don't know if this problem has always been there as I've never had a single LED wired into anything, and as it appears I'm getting around 140v popping into view on the circuit when it's "off" at the switches it's hard to know where to start looking. Sensibly I think I expected there to be a short in one of the 3 core cables, but I eliminated this by the simple use of wasting a few hours in a crawl space replacing it on one of the circuits before bothering to see if it affected more than one circuit, which it does.

So. Any ideas? The weirdness for me is that it's only when wired 2-way. What do you think?

 

[Ray4438]

Strappers are picking up inductance

You will need to put a filter over the neutral and line at lamp quite common with led lamps you can get filters from maplin

 

[Wuffles]

Well, the plan isn't to use just one LED, I just happened to have it handy as a visual tester if you like. Should I not be concerned with the apparent 140v "popping" on the line? Or is the LED actually the cause? In which case, I have no problem?

Thanks.

 

[NozSpark]

Its called capacitive coupling, basically its an induced voltage in the 2 way switching which is so small it isn't noticeable with incandescent lamps.. LED and CFL lamps electronics allow this voltage to build until it strikes the lamp but as it is small it is discharged immediately,,, and the cycle continues

There is nothing wrong, but it can be stopped by using filament lamps,, or by fitting a snubber (?) at one of the fittings

 

[Wuffles]

You know what. I'd buy each and every one of you a beer for that answer. If I wasn't still picking fibreglass insulation out of my ears. My fault for not asking beforehand.

Thank you all!

 

[NozSpark]

Guinness  

Cheers

 

[SPECIAL LOCATION]

There are loads of other threads on this subject such as this one;

http://www.talk.electricianforum.co.uk/topic/22668-11w-low-energy-bc-lamp-flashing-with-switch-off/

 

[Wuffles]

Yes apologies, I'd googled a number of different phrases generally and they all ended up with someone trying to flog me a surge protector. My fixation regarding the addition of a 2-way cable causing the problem made searching even harder.